xref: /frameworks/base/core/java/android/app/SearchManager.java

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.app;

import android.content.ComponentName;
import android.content.ContentResolver;
import android.content.Context;
import android.content.DialogInterface;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.text.TextUtils;
import android.util.Log;
import android.view.KeyEvent;

import java.util.List;

/**
 * This class provides access to the system search services.
 *
 * <p>In practice, you won't interact with this class directly, as search
 * services are provided through methods in {@link android.app.Activity Activity}
 * methods and the the {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH}
 * {@link android.content.Intent Intent}.  This class does provide a basic
 * overview of search services and how to integrate them with your activities.
 * If you do require direct access to the SearchManager, do not instantiate
 * this class directly; instead, retrieve it through
 * {@link android.content.Context#getSystemService
 * context.getSystemService(Context.SEARCH_SERVICE)}.
 *
 * <p>Topics covered here:
 * <ol>
 * <li><a href="#DeveloperGuide">Developer Guide</a>
 * <li><a href="#HowSearchIsInvoked">How Search Is Invoked</a>
 * <li><a href="#ImplementingSearchForYourApp">Implementing Search for Your App</a>
 * <li><a href="#Suggestions">Search Suggestions</a>
 * <li><a href="#ExposingSearchSuggestionsToQuickSearchBox">Exposing Search Suggestions to
 * Quick Search Box</a></li>
 * <li><a href="#ActionKeys">Action Keys</a>
 * <li><a href="#SearchabilityMetadata">Searchability Metadata</a>
 * <li><a href="#PassingSearchContext">Passing Search Context</a>
 * <li><a href="#ProtectingUserPrivacy">Protecting User Privacy</a>
 * </ol>
 *
 * <a name="DeveloperGuide"></a>
 * <h3>Developer Guide</h3>
 *
 * <p>The ability to search for user, system, or network based data is considered to be
 * a core user-level feature of the Android platform.  At any time, the user should be
 * able to use a familiar command, button, or keystroke to invoke search, and the user
 * should be able to search any data which is available to them.
 *
 * <p>To make search appear to the user as a seamless system-wide feature, the application
 * framework centrally controls it, offering APIs to individual applications to control how they
 * are searched. Applications can customize how search is invoked, how the search dialog looks,
 * and what type of search results are available, including suggestions that are available as the
 * user types.
 *
 * <p>Even applications which are not searchable will by default support the invocation of
 * search to trigger Quick Search Box, the system's 'global search'.
 *
 * <a name="HowSearchIsInvoked"></a>
 * <h3>How Search Is Invoked</h3>
 *
 * <p>Unless impossible or inapplicable, all applications should support
 * invoking the search UI.  This means that when the user invokes the search command,
 * a search UI will be presented to them.  The search command is currently defined as a menu
 * item called "Search" (with an alphabetic shortcut key of "S"), or on many devices, a dedicated
 * search button key.
 * <p>If your application is not inherently searchable, the default implementation will cause
 * the search UI to be invoked in a "global search" mode known as Quick Search Box.  As the user
 * types, search suggestions from across the device and the web will be surfaced, and if they
 * click the "Search" button, this will bring the browser to the front and will launch a web-based
 * search.  The user will be able to click the "Back" button and return to your application.
 * <p>In general this is implemented by your activity, or the {@link android.app.Activity Activity}
 * base class, which captures the search command and invokes the SearchManager to
 * display and operate the search UI.  You can also cause the search UI to be presented in response
 * to user keystrokes in your activity (for example, to instantly start filter searching while
 * viewing a list and typing any key).
 * <p>The search UI is presented as a floating
 * window and does not cause any change in the activity stack.  If the user
 * cancels search, the previous activity re-emerges.  If the user launches a
 * search, this will be done by sending a search {@link android.content.Intent Intent} (see below),
 * and the normal intent-handling sequence will take place (your activity will pause,
 * etc.)
 * <p><b>What you need to do:</b> First, you should consider the way in which you want to
 * handle invoking search.  There are four broad (and partially overlapping) categories for
 * you to choose from.
 * <ul><li>You can capture the search command yourself, by including a <i>search</i>
 * button or menu item - and invoking the search UI directly.</li>
 * <li>You can provide a <i>type-to-search</i> feature, in which search is invoked automatically
 * when the user enters any characters.</li>
 * <li>Even if your application is not inherently searchable, you can allow global search,
 * via the search key (or even via a search menu item).
 * <li>You can disable search entirely.  This should only be used in very rare circumstances,
 * as search is a system-wide feature and users will expect it to be available in all contexts.</li>
 * </ul>
 *
 * <p><b>How to define a search menu.</b>  The system provides the following resources which may
 * be useful when adding a search item to your menu:
 * <ul><li>android.R.drawable.ic_search_category_default is an icon you can use in your menu.</li>
 * <li>{@link #MENU_KEY SearchManager.MENU_KEY} is the recommended alphabetic shortcut.</li>
 * </ul>
 *
 * <p><b>How to invoke search directly.</b>  In order to invoke search directly, from a button
 * or menu item, you can launch a generic search by calling
 * {@link android.app.Activity#onSearchRequested onSearchRequested} as shown:
 * <pre class="prettyprint">
 * onSearchRequested();</pre>
 *
 * <p><b>How to implement type-to-search.</b>  While setting up your activity, call
 * {@link android.app.Activity#setDefaultKeyMode setDefaultKeyMode}:
 * <pre class="prettyprint">
 * setDefaultKeyMode(DEFAULT_KEYS_SEARCH_LOCAL);   // search within your activity
 * setDefaultKeyMode(DEFAULT_KEYS_SEARCH_GLOBAL);  // search using platform global search</pre>
 *
 * <p><b>How to enable global search with Quick Search Box.</b>  In addition to searching within
 * your activity or application, you can also use the Search Manager to invoke a platform-global
 * search, which uses Quick Search Box to search across the device and the web. There are two ways
 * to do this:
 * <ul><li>You can simply define "search" within your application or activity to mean global search.
 * This is described in more detail in the
 * <a href="#SearchabilityMetadata">Searchability Metadata</a> section.  Briefly, you will
 * add a single meta-data entry to your manifest, declaring that the default search
 * for your application is "*".  This indicates to the system that no application-specific
 * search activity is provided, and that it should launch web-based search instead.</li>
 * <li>Simply do nothing and the default implementation of
 * {@link android.app.Activity#onSearchRequested} will cause global search to be triggered.
 * (You can also always trigger search via a direct call to {@link android.app.Activity#startSearch}.
 * This is most useful if you wish to provide local searchability <i>and</i> access to global
 * search.)</li></ul>
 *
 * <p><b>How to disable search from your activity.</b> Search is a system-wide feature and users
 * will expect it to be available in all contexts.  If your UI design absolutely precludes
 * launching search, override {@link android.app.Activity#onSearchRequested onSearchRequested}
 * as shown:
 * <pre class="prettyprint">
 * &#64;Override
 * public boolean onSearchRequested() {
 *    return false;
 * }</pre>
 *
 * <p><b>Managing focus and knowing if search is active.</b>  The search UI is not a separate
 * activity, and when the UI is invoked or dismissed, your activity will not typically be paused,
 * resumed, or otherwise notified by the methods defined in
 * <a href="{@docRoot}guide/topics/fundamentals.html#actlife">Application Fundamentals:
 * Activity Lifecycle</a>.  The search UI is
 * handled in the same way as other system UI elements which may appear from time to time, such as
 * notifications, screen locks, or other system alerts:
 * <p>When the search UI appears, your activity will lose input focus.
 * <p>When the search activity is dismissed, there are three possible outcomes:
 * <ul><li>If the user simply canceled the search UI, your activity will regain input focus and
 * proceed as before.  See {@link #setOnDismissListener} and {@link #setOnCancelListener} if you
 * required direct notification of search dialog dismissals.</li>
 * <li>If the user launched a search, and this required switching to another activity to receive
 * and process the search {@link android.content.Intent Intent}, your activity will receive the
 * normal sequence of activity pause or stop notifications.</li>
 * <li>If the user launched a search, and the current activity is the recipient of the search
 * {@link android.content.Intent Intent}, you will receive notification via the
 * {@link android.app.Activity#onNewIntent onNewIntent()} method.</li></ul>
 * <p>This list is provided in order to clarify the ways in which your activities will interact with
 * the search UI.  More details on searchable activities and search intents are provided in the
 * sections below.
 *
 * <a name="ImplementingSearchForYourApp"></a>
 * <h3>Implementing Search for Your App</h3>
 *
 * <p>The following steps are necessary in order to implement search.
 * <ul>
 * <li>Implement search invocation as described above.  (Strictly speaking,
 * these are decoupled, but it would make little sense to be "searchable" but not
 * "search-invoking".)</li>
 * <li>Your application should have an activity that takes a search string and
 * converts it to a list of results.  This could be your primary display activity
 * or it could be a dedicated search results activity.  This is your <i>searchable</i>
 * activity and every query-search application must have one.</li>
 * <li>In the searchable activity, in onCreate(), you must receive and handle the
 * {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH}
 * {@link android.content.Intent Intent}.  The text to search (query string) for is provided by
 * calling
 * {@link #QUERY getStringExtra(SearchManager.QUERY)}.</li>
 * <li>To identify and support your searchable activity, you'll need to
 * provide an XML file providing searchability configuration parameters, a reference to that
 * in your searchable activity's
 * <a href="{@docRoot}guide/topics/manifest/manifest-intro.html">manifest</a> entry, and an
 * intent-filter declaring that you can receive ACTION_SEARCH intents. This is described in more
 * detail in the <a href="#SearchabilityMetadata">Searchability Metadata</a> section.</li>
 * <li>Your <a href="{@docRoot}guide/topics/manifest/manifest-intro.html">manifest</a> also needs a
 * metadata entry providing a global reference to the searchable activity. This is the "glue"
 * directing the search UI, when invoked from any of your <i>other</i> activities, to use your
 * application as the default search context.  This is also described in more detail in the
 * <a href="#SearchabilityMetadata">Searchability Metadata</a> section.</li>
 * <li>Finally, you may want to define your search results activity as single-top with the
 * {@link android.R.attr#launchMode singleTop} launchMode flag.  This allows the system
 * to launch searches from/to the same activity without creating a pile of them on the
 * activity stack.  If you do this, be sure to also override
 * {@link android.app.Activity#onNewIntent onNewIntent} to handle the
 * updated intents (with new queries) as they arrive.</li>
 * </ul>
 *
 * <p>Code snippet showing handling of intents in your search activity:
 * <pre class="prettyprint">
 * &#64;Override
 * protected void onCreate(Bundle icicle) {
 *     super.onCreate(icicle);
 *
 *     final Intent queryIntent = getIntent();
 *     final String queryAction = queryIntent.getAction();
 *     if (Intent.ACTION_SEARCH.equals(queryAction)) {
 *         doSearchWithIntent(queryIntent);
 *     }
 * }
 *
 * private void doSearchWithIntent(final Intent queryIntent) {
 *     final String queryString = queryIntent.getStringExtra(SearchManager.QUERY);
 *     doSearchWithQuery(queryString);
 * }</pre>
 *
 * <a name="Suggestions"></a>
 * <h3>Search Suggestions</h3>
 *
 * <p>A powerful feature of the search system is the ability of any application to easily provide
 * live "suggestions" in order to prompt the user.  Each application implements suggestions in a
 * different, unique, and appropriate way.  Suggestions be drawn from many sources, including but
 * not limited to:
 * <ul>
 * <li>Actual searchable results (e.g. names in the address book)</li>
 * <li>Recently entered queries</li>
 * <li>Recently viewed data or results</li>
 * <li>Contextually appropriate queries or results</li>
 * <li>Summaries of possible results</li>
 * </ul>
 *
 * <p>Once an application is configured to provide search suggestions, those same suggestions can
 * easily be made available to the system-wide Quick Search Box, providing faster access to its
 * content from one central prominent place. See
 * <a href="#ExposingSearchSuggestionsToQuickSearchBox">Exposing Search Suggestions to Quick Search
 * Box</a> for more details.
 *
 * <p>The primary form of suggestions is known as <i>queried suggestions</i> and is based on query
 * text that the user has already typed.  This would generally be based on partial matches in
 * the available data.  In certain situations - for example, when no query text has been typed yet -
 * an application may also opt to provide <i>zero-query suggestions</i>.
 * These would typically be drawn from the same data source, but because no partial query text is
 * available, they should be weighted based on other factors - for example, most recent queries
 * or most recent results.
 *
 * <p><b>Overview of how suggestions are provided.</b>  Suggestions are accessed via a
 * {@link android.content.ContentProvider Content Provider}. When the search manager identifies a
 * particular activity as searchable, it will check for certain metadata which indicates that
 * there is also a source of suggestions.  If suggestions are provided, the following steps are
 * taken.
 * <ul><li>Using formatting information found in the metadata, the user's query text (whatever
 * has been typed so far) will be formatted into a query and sent to the suggestions
 * {@link android.content.ContentProvider Content Provider}.</li>
 * <li>The suggestions {@link android.content.ContentProvider Content Provider} will create a
 * {@link android.database.Cursor Cursor} which can iterate over the possible suggestions.</li>
 * <li>The search manager will populate a list using display data found in each row of the cursor,
 * and display these suggestions to the user.</li>
 * <li>If the user types another key, or changes the query in any way, the above steps are repeated
 * and the suggestions list is updated or repopulated.</li>
 * <li>If the user clicks or touches the "GO" button, the suggestions are ignored and the search is
 * launched using the normal {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} type of
 * {@link android.content.Intent Intent}.</li>
 * <li>If the user uses the directional controls to navigate the focus into the suggestions list,
 * the query text will be updated while the user navigates from suggestion to suggestion.  The user
 * can then click or touch the updated query and edit it further.  If the user navigates back to
 * the edit field, the original typed query is restored.</li>
 * <li>If the user clicks or touches a particular suggestion, then a combination of data from the
 * cursor and
 * values found in the metadata are used to synthesize an Intent and send it to the application.
 * Depending on the design of the activity and the way it implements search, this might be a
 * {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} (in order to launch a query), or it
 * might be a {@link android.content.Intent#ACTION_VIEW ACTION_VIEW}, in order to proceed directly
 * to display of specific data.</li>
 * </ul>
 *
 * <p><b>Simple Recent-Query-Based Suggestions.</b>  The Android framework provides a simple Search
 * Suggestions provider, which simply records and replays recent queries.  For many applications,
 * this will be sufficient.  The basic steps you will need to
 * do, in order to use the built-in recent queries suggestions provider, are as follows:
 * <ul>
 * <li>Implement and test query search, as described in the previous sections.</li>
 * <li>Create a Provider within your application by extending
 * {@link android.content.SearchRecentSuggestionsProvider}.</li>
 * <li>Create a manifest entry describing your provider.</li>
 * <li>Update your searchable activity's XML configuration file with information about your
 * provider.</li>
 * <li>In your searchable activities, capture any user-generated queries and record them
 * for future searches by calling {@link android.provider.SearchRecentSuggestions#saveRecentQuery}.
 * </li>
 * </ul>
 * <p>For complete implementation details, please refer to
 * {@link android.content.SearchRecentSuggestionsProvider}.  The rest of the information in this
 * section should not be necessary, as it refers to custom suggestions providers.
 *
 * <p><b>Creating a Customized Suggestions Provider:</b>  In order to create more sophisticated
 * suggestion providers, you'll need to take the following steps:
 * <ul>
 * <li>Implement and test query search, as described in the previous sections.</li>
 * <li>Decide how you wish to <i>receive</i> suggestions.  Just like queries that the user enters,
 * suggestions will be delivered to your searchable activity as
 * {@link android.content.Intent Intent} messages;  Unlike simple queries, you have quite a bit of
 * flexibility in forming those intents.  A query search application will probably
 * wish to continue receiving the {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH}
 * {@link android.content.Intent Intent}, which will launch a query search using query text as
 * provided by the suggestion.  A filter search application will probably wish to
 * receive the {@link android.content.Intent#ACTION_VIEW ACTION_VIEW}
 * {@link android.content.Intent Intent}, which will take the user directly to a selected entry.
 * Other interesting suggestions, including hybrids, are possible, and the suggestion provider
 * can easily mix-and-match results to provide a richer set of suggestions for the user.  Finally,
 * you'll need to update your searchable activity (or other activities) to receive the intents
 * as you've defined them.</li>
 * <li>Implement a Content Provider that provides suggestions.  If you already have one, and it
 * has access to your suggestions data, you can use that provider. If not, you'll have to create
 * one. You'll also provide information about your Content Provider in your
 * package's <a href="{@docRoot}guide/topics/manifest/manifest-intro.html">manifest</a>.</li>
 * <li>Update your searchable activity's XML configuration file.  There are two categories of
 * information used for suggestions:
 * <ul><li>The first is (required) data that the search manager will
 * use to format the queries which are sent to the Content Provider.</li>
 * <li>The second is (optional) parameters to configure structure
 * if intents generated by suggestions.</li></li>
 * </ul>
 * </ul>
 *
 * <p><b>Configuring your Content Provider to Receive Suggestion Queries.</b>  The basic job of
 * a search suggestions {@link android.content.ContentProvider Content Provider} is to provide
 * "live" (while-you-type) conversion of the user's query text into a set of zero or more
 * suggestions.  Each application is free to define the conversion, and as described above there are
 * many possible solutions.  This section simply defines how to communicate with the suggestion
 * provider.
 *
 * <p>The Search Manager must first determine if your package provides suggestions.  This is done
 * by examination of your searchable meta-data XML file.  The android:searchSuggestAuthority
 * attribute, if provided, is the signal to obtain & display suggestions.
 *
 * <p>Every query includes a Uri, and the Search Manager will format the Uri as shown:
 * <p><pre class="prettyprint">
 * content:// your.suggest.authority / your.suggest.path / SearchManager.SUGGEST_URI_PATH_QUERY</pre>
 *
 * <p>Your Content Provider can receive the query text in one of two ways.
 * <ul>
 * <li><b>Query provided as a selection argument.</b>  If you define the attribute value
 * android:searchSuggestSelection and include a string, this string will be passed as the
 * <i>selection</i> parameter to your Content Provider's query function.  You must define a single
 * selection argument, using the '?' character.  The user's query text will be passed to you
 * as the first element of the selection arguments array.</li>
 * <li><b>Query provided with Data Uri.</b>  If you <i>do not</i> define the attribute value
 * android:searchSuggestSelection, then the Search Manager will append another "/" followed by
 * the user's query to the query Uri.  The query will be encoding using Uri encoding rules - don't
 * forget to decode it.  (See {@link android.net.Uri#getPathSegments} and
 * {@link android.net.Uri#getLastPathSegment} for helpful utilities you can use here.)</li>
 * </ul>
 *
 * <p><b>Providing access to Content Providers that require permissions.</b>  If your content
 * provider declares an android:readPermission in your application's manifest, you must provide
 * access to the search infrastructure to the search suggestion path by including a path-permission
 * that grants android:readPermission access to "android.permission.GLOBAL_SEARCH".  Granting access
 * explicitly to the search infrastructure ensures it will be able to access the search suggestions
 * without needing to know ahead of time any other details of the permissions protecting your
 * provider.  Content providers that require no permissions are already available to the search
 * infrastructure.  Here is an example of a provider that protects access to it with permissions,
 * and provides read access to the search infrastructure to the path that it expects to receive the
 * suggestion query on:
 * <pre class="prettyprint">
 * &lt;provider android:name="MyProvider" android:authorities="myprovider"
 *        android:readPermission="android.permission.READ_MY_DATA"
 *        android:writePermission="android.permission.WRITE_MY_DATA"&gt;
 *    &lt;path-permission android:path="/search_suggest_query"
 *            android:readPermission="android.permission.GLOBAL_SEARCH" /&gt;
 * &lt;/provider&gt;
 * </pre>
 *
 * <p><b>Handling empty queries.</b>  Your application should handle the "empty query"
 * (no user text entered) case properly, and generate useful suggestions in this case.  There are a
 * number of ways to do this;  Two are outlined here:
 * <ul><li>For a simple filter search of local data, you could simply present the entire dataset,
 * unfiltered.  (example: People)</li>
 * <li>For a query search, you could simply present the most recent queries.  This allows the user
 * to quickly repeat a recent search.</li></ul>
 *
 * <p><b>The Format of Individual Suggestions.</b>  Your suggestions are communicated back to the
 * Search Manager by way of a {@link android.database.Cursor Cursor}.  The Search Manager will
 * usually pass a null Projection, which means that your provider can simply return all appropriate
 * columns for each suggestion.  The columns currently defined are:
 *
 * <table border="2" width="85%" align="center" frame="hsides" rules="rows">
 *
 *     <thead>
 *     <tr><th>Column Name</th> <th>Description</th> <th>Required?</th></tr>
 *     </thead>
 *
 *     <tbody>
 *     <tr><th>{@link #SUGGEST_COLUMN_FORMAT}</th>
 *         <td><i>Unused - can be null.</i></td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>{@link #SUGGEST_COLUMN_TEXT_1}</th>
 *         <td>This is the line of text that will be presented to the user as the suggestion.</td>
 *         <td align="center">Yes</td>
 *     </tr>
 *
 *     <tr><th>{@link #SUGGEST_COLUMN_TEXT_2}</th>
 *         <td>If your cursor includes this column, then all suggestions will be provided in a
 *             two-line format.  The data in this column will be displayed as a second, smaller
 *             line of text below the primary suggestion, or it can be null or empty to indicate no
 *             text in this row's suggestion.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>{@link #SUGGEST_COLUMN_ICON_1}</th>
 *         <td>If your cursor includes this column, then all suggestions will be provided in an
 *             icons+text format.  This value should be a reference to the icon to
 *             draw on the left side, or it can be null or zero to indicate no icon in this row.
 *             </td>
 *         <td align="center">No.</td>
 *     </tr>
 *
 *     <tr><th>{@link #SUGGEST_COLUMN_ICON_2}</th>
 *         <td>If your cursor includes this column, then all suggestions will be provided in an
 *             icons+text format.  This value should be a reference to the icon to
 *             draw on the right side, or it can be null or zero to indicate no icon in this row.
 *             </td>
 *         <td align="center">No.</td>
 *     </tr>
 *
 *     <tr><th>{@link #SUGGEST_COLUMN_INTENT_ACTION}</th>
 *         <td>If this column exists <i>and</i> this element exists at the given row, this is the
 *             action that will be used when forming the suggestion's intent.  If the element is
 *             not provided, the action will be taken from the android:searchSuggestIntentAction
 *             field in your XML metadata.  <i>At least one of these must be present for the
 *             suggestion to generate an intent.</i>  Note:  If your action is the same for all
 *             suggestions, it is more efficient to specify it using XML metadata and omit it from
 *             the cursor.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>{@link #SUGGEST_COLUMN_INTENT_DATA}</th>
 *         <td>If this column exists <i>and</i> this element exists at the given row, this is the
 *             data that will be used when forming the suggestion's intent.  If the element is not
 *             provided, the data will be taken from the android:searchSuggestIntentData field in
 *             your XML metadata.  If neither source is provided, the Intent's data field will be
 *             null.  Note:  If your data is the same for all suggestions, or can be described
 *             using a constant part and a specific ID, it is more efficient to specify it using
 *             XML metadata and omit it from the cursor.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>{@link #SUGGEST_COLUMN_INTENT_DATA_ID}</th>
 *         <td>If this column exists <i>and</i> this element exists at the given row, then "/" and
 *             this value will be appended to the data field in the Intent.  This should only be
 *             used if the data field has already been set to an appropriate base string.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>{@link #SUGGEST_COLUMN_INTENT_EXTRA_DATA}</th>
 *         <td>If this column exists <i>and</i> this element exists at a given row, this is the
 *             data that will be used when forming the suggestion's intent.  If not provided,
 *             the Intent's extra data field will be null.  This column allows suggestions to
 *             provide additional arbitrary data which will be included as an extra under the
 *             key {@link #EXTRA_DATA_KEY}.</td>
 *         <td align="center">No.</td>
 *     </tr>
 *
 *     <tr><th>{@link #SUGGEST_COLUMN_QUERY}</th>
 *         <td>If this column exists <i>and</i> this element exists at the given row, this is the
 *             data that will be used when forming the suggestion's query.</td>
 *         <td align="center">Required if suggestion's action is
 *             {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH}, optional otherwise.</td>
 *     </tr>
 *
 *     <tr><th>{@link #SUGGEST_COLUMN_SHORTCUT_ID}</th>
 *         <td>This column is used to indicate whether a search suggestion should be stored as a
 *             shortcut, and whether it should be validated.  Shortcuts are usually formed when the
 *             user clicks a suggestion from Quick Search Box.  If missing, the result will be
 *             stored as a shortcut and never refreshed.  If set to
 *             {@link #SUGGEST_NEVER_MAKE_SHORTCUT}, the result will not be stored as a shortcut.
 *             Otherwise, the shortcut id will be used to check back for for an up to date
 *             suggestion using {@link #SUGGEST_URI_PATH_SHORTCUT}. Read more about shortcut
 *             refreshing in the section about
 *             <a href="#ExposingSearchSuggestionsToQuickSearchBox">exposing search suggestions to
 *             Quick Search Box</a>.</td>
 *         <td align="center">No.  Only applicable to sources included in Quick Search Box.</td>
 *     </tr>
 *
 *     <tr><th>{@link #SUGGEST_COLUMN_SPINNER_WHILE_REFRESHING}</th>
 *         <td>This column is used to specify that a spinner should be shown in lieu of an icon2
 *             while the shortcut of this suggestion is being refreshed in Quick Search Box.</td>
 *         <td align="center">No.  Only applicable to sources included in Quick Search Box.</td>
 *     </tr>
 *
 *     <tr><th><i>Other Columns</i></th>
 *         <td>Finally, if you have defined any <a href="#ActionKeys">Action Keys</a> and you wish
 *             for them to have suggestion-specific definitions, you'll need to define one
 *             additional column per action key.  The action key will only trigger if the
 *             currently-selection suggestion has a non-empty string in the corresponding column.
 *             See the section on <a href="#ActionKeys">Action Keys</a> for additional details and
 *             implementation steps.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     </tbody>
 * </table>
 *
 * <p>Clearly there are quite a few permutations of your suggestion data, but in the next section
 * we'll look at a few simple combinations that you'll select from.
 *
 * <p><b>The Format Of Intents Sent By Search Suggestions.</b>  Although there are many ways to
 * configure these intents, this document will provide specific information on just a few of them.
 * <ul><li><b>Launch a query.</b>  In this model, each suggestion represents a query that your
 * searchable activity can perform, and the {@link android.content.Intent Intent} will be formatted
 * exactly like those sent when the user enters query text and clicks the "GO" button:
 *   <ul>
 *   <li><b>Action:</b> {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} provided
 *   using your XML metadata (android:searchSuggestIntentAction).</li>
 *   <li><b>Data:</b> empty (not used).</li>
 *   <li><b>Query:</b> query text supplied by the cursor.</li>
 *   </ul>
 * </li>
 * <li><b>Go directly to a result, using a complete Data Uri.</b>  In this model, the user will be
 * taken directly to a specific result.
 *   <ul>
 *   <li><b>Action:</b> {@link android.content.Intent#ACTION_VIEW ACTION_VIEW}</li>
 *   <li><b>Data:</b> a complete Uri, supplied by the cursor, that identifies the desired data.</li>
 *   <li><b>Query:</b> query text supplied with the suggestion (probably ignored)</li>
 *   </ul>
 * </li>
 * <li><b>Go directly to a result, using a synthesized Data Uri.</b>  This has the same result
 * as the previous suggestion, but provides the Data Uri in a different way.
 *   <ul>
 *   <li><b>Action:</b> {@link android.content.Intent#ACTION_VIEW ACTION_VIEW}</li>
 *   <li><b>Data:</b> The search manager will assemble a Data Uri using the following elements:
 *   a Uri fragment provided in your XML metadata (android:searchSuggestIntentData), followed by
 *   a single "/", followed by the value found in the {@link #SUGGEST_COLUMN_INTENT_DATA_ID}
 *   entry in your cursor.</li>
 *   <li><b>Query:</b> query text supplied with the suggestion (probably ignored)</li>
 *   </ul>
 * </li>
 * </ul>
 * <p>This list is not meant to be exhaustive.  Applications should feel free to define other types
 * of suggestions.  For example, you could reduce long lists of results to summaries, and use one
 * of the above intents (or one of your own) with specially formatted Data Uri's to display more
 * detailed results.  Or you could display textual shortcuts as suggestions, but launch a display
 * in a more data-appropriate format such as media artwork.
 *
 * <p><b>Suggestion Rewriting.</b>  If the user navigates through the suggestions list, the UI
 * may temporarily rewrite the user's query with a query that matches the currently selected
 * suggestion.  This enables the user to see what query is being suggested, and also allows the user
 * to click or touch in the entry EditText element and make further edits to the query before
 * dispatching it.  In order to perform this correctly, the Search UI needs to know exactly what
 * text to rewrite the query with.
 *
 * <p>For each suggestion, the following logic is used to select a new query string:
 * <ul><li>If the suggestion provides an explicit value in the {@link #SUGGEST_COLUMN_QUERY}
 * column, this value will be used.</li>
 * <li>If the metadata includes the queryRewriteFromData flag, and the suggestion provides an
 * explicit value for the intent Data field, this Uri will be used.  Note that this should only be
 * used with Uri's that are intended to be user-visible, such as HTTP.  Internal Uri schemes should
 * not be used in this way.</li>
 * <li>If the metadata includes the queryRewriteFromText flag, the text in
 * {@link #SUGGEST_COLUMN_TEXT_1} will be used.  This should be used for suggestions in which no
 * query text is provided and the SUGGEST_COLUMN_INTENT_DATA values are not suitable for user
 * inspection and editing.</li></ul>
 *
 * <a name="ExposingSearchSuggestionsToQuickSearchBox"></a>
 * <h3>Exposing Search Suggestions to Quick Search Box</h3>
 *
 * <p>Once your application is set up to provide search suggestions, making them available to the
 * globally accessable Quick Search Box is as easy as setting android:includeInGlobalSearch to
 * "true" in your searchable metadata file.  Beyond that, here are some more details of how
 * suggestions interact with Quick Search Box, and optional ways that you may customize suggestions
 * for your application.
 *
 * <p><b>Important Note:</b>  By default, your application will not be enabled as a suggestion
 * provider (or "searchable item") in Quick Search Box. Once your app is installed, the user must
 * enable it as a "searchable item" in the Search settings in order to receive your app's
 * suggestions in Quick Search Box. You should consider how to message this to users of your app -
 * perhaps with a note to the user the first time they launch the app about how to enable search
 * suggestions. This gives your app a chance to be queried for suggestions as the user types into
 * Quick Search Box, though exactly how or if your suggestions will be surfaced is decided by Quick
 * Search Box.
 *
 * <p><b>Source Ranking:</b>  Once your application's search results are made available to Quick
 * Search Box, how they surface to the user for a particular query will be determined as appropriate
 * by Quick Search Box ranking. This may depend on how many other apps have results for that query,
 * and how often the user has clicked on your results compared to the other apps - but there is no
 * guarantee about how ranking will occur, or whether your app's suggestions will show at all for
 * a given query.  In general, you can expect that providing quality results will increase the
 * likelihood that your app's suggestions are provided in a prominent position, and apps that
 * provide lower quality suggestions will be more likely to be ranked lower and/or not displayed.
 *
 * <p><b>Search Settings:</b>  Each app that is available to Quick Search Box has an entry in the
 * system settings where the user can enable or disable the inclusion of its results.  Below the
 * name of the application, each application may provide a brief description of what kind of
 * information will be made available via a search settings description string pointed to by the
 * android:searchSettingsDescription attribute in the searchable metadata. Note that the
 * user will need to visit this settings menu to enable search suggestions for your app before your
 * app will have a chance to provide search suggestions to Quick Search Box - see the section
 * called "Important Note" above.
 *
 * <p><b>Shortcuts:</b>  Suggestions that are clicked on by the user may be automatically made into
 * shortcuts, which are suggestions that have been copied from your provider in order to be quickly
 * displayed without the need to re-query the original sources. Shortcutted suggestions may be
 * displayed for the query that yielded the suggestion and for any prefixes of that query. You can
 * request how to have your app's suggestions made into shortcuts, and whether they should be
 * refreshed, using the {@link #SUGGEST_COLUMN_SHORTCUT_ID} column:
 * <ul><li>Suggestions that do not include a shortcut id column will be made into shortcuts and
 * never refreshed.  This makes sense for suggestions that refer to data that will never be changed
 * or removed.</li>
 * <li>Suggestions that include a shortcut id will be re-queried for a fresh version of the
 * suggestion each time the shortcut is displayed.  The shortcut will be quickly displayed with
 * whatever data was most recently available until the refresh query returns, after which the
 * suggestion will be dynamically refreshed with the up to date information.  The shortcut refresh
 * query will be sent to your suggestion provider with a uri of {@link #SUGGEST_URI_PATH_SHORTCUT}.
 * The result should contain one suggestion using the same columns as the suggestion query, or be
 * empty, indicating that the shortcut is no longer valid.  Shortcut ids make sense when referring
 * to data that may change over time, such as a contact's presence status.  If a suggestion refers
 * to data that could take longer to refresh, such as a network based refresh of a stock quote, you
 * may include {@link #SUGGEST_COLUMN_SPINNER_WHILE_REFRESHING} to show a progress spinner for the
 * right hand icon until the refresh is complete.</li>
 * <li>Finally, to prevent a suggestion from being copied into a shortcut, you may provide a
 * shortcut id with a value of {@link #SUGGEST_NEVER_MAKE_SHORTCUT}.</li></ul>
 *
 * Note that Quick Search Box will ultimately decide whether to shortcut your app's suggestions,
 * considering these values as a strong request from your application.
 *
 * <a name="ActionKeys"></a>
 * <h3>Action Keys</h3>
 *
 * <p>Searchable activities may also wish to provide shortcuts based on the various action keys
 * available on the device.  The most basic example of this is the contacts app, which enables the
 * green "dial" key for quick access during searching.  Not all action keys are available on
 * every device, and not all are allowed to be overriden in this way.  (For example, the "Home"
 * key must always return to the home screen, with no exceptions.)
 *
 * <p>In order to define action keys for your searchable application, you must do two things.
 *
 * <ul>
 * <li>You'll add one or more <i>actionkey</i> elements to your searchable metadata configuration
 * file.  Each element defines one of the keycodes you are interested in,
 * defines the conditions under which they are sent, and provides details
 * on how to communicate the action key event back to your searchable activity.</li>
 * <li>In your broadcast receiver, if you wish, you can check for action keys by checking the
 * extras field of the {@link android.content.Intent Intent}.</li>
 * </ul>
 *
 * <p><b>Updating metadata.</b>  For each keycode of interest, you must add an &lt;actionkey&gt;
 * element.  Within this element you must define two or three attributes.  The first attribute,
 * &lt;android:keycode&gt;, is required;  It is the key code of the action key event, as defined in
 * {@link android.view.KeyEvent}.  The remaining two attributes define the value of the actionkey's
 * <i>message</i>, which will be passed to your searchable activity in the
 * {@link android.content.Intent Intent} (see below for more details).  Although each of these
 * attributes is optional, you must define one or both for the action key to have any effect.
 * &lt;android:queryActionMsg&gt; provides the message that will be sent if the action key is
 * pressed while the user is simply entering query text.  &lt;android:suggestActionMsgColumn&gt;
 * is used when action keys are tied to specific suggestions.  This attribute provides the name
 * of a <i>column</i> in your suggestion cursor;  The individual suggestion, in that column,
 * provides the message.  (If the cell is empty or null, that suggestion will not work with that
 * action key.)
 * <p>See the <a href="#SearchabilityMetadata">Searchability Metadata</a> section for more details
 * and examples.
 *
 * <p><b>Receiving Action Keys</b>  Intents launched by action keys will be specially marked
 * using a combination of values.  This enables your searchable application to examine the intent,
 * if necessary, and perform special processing.  For example, clicking a suggested contact might
 * simply display them;  Selecting a suggested contact and clicking the dial button might
 * immediately call them.
 *
 * <p>When a search {@link android.content.Intent Intent} is launched by an action key, two values
 * will be added to the extras field.
 * <ul>
 * <li>To examine the key code, use {@link android.content.Intent#getIntExtra
 * getIntExtra(SearchManager.ACTION_KEY)}.</li>
 * <li>To examine the message string, use {@link android.content.Intent#getStringExtra
 * getStringExtra(SearchManager.ACTION_MSG)}</li>
 * </ul>
 *
 * <a name="SearchabilityMetadata"></a>
 * <h3>Searchability Metadata</h3>
 *
 * <p>Every activity that is searchable must provide a small amount of additional information
 * in order to properly configure the search system.  This controls the way that your search
 * is presented to the user, and controls for the various modalities described previously.
 *
 * <p>If your application is not searchable,
 * then you do not need to provide any search metadata, and you can skip the rest of this section.
 * When this search metadata cannot be found, the search manager will assume that the activity
 * does not implement search.  (Note: to implement web-based search, you will need to add
 * the android.app.default_searchable metadata to your manifest, as shown below.)
 *
 * <p>Values you supply in metadata apply only to each local searchable activity.  Each
 * searchable activity can define a completely unique search experience relevant to its own
 * capabilities and user experience requirements, and a single application can even define multiple
 * searchable activities.
 *
 * <p><b>Metadata for searchable activity.</b>  As with your search implementations described
 * above, you must first identify which of your activities is searchable.  In the
 * <a href="{@docRoot}guide/topics/manifest/manifest-intro.html">manifest</a> entry for this activity, you must
 * provide two elements:
 * <ul><li>An intent-filter specifying that you can receive and process the
 * {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} {@link android.content.Intent Intent}.
 * </li>
 * <li>A reference to a small XML file (typically called "searchable.xml") which contains the
 * remaining configuration information for how your application implements search.</li></ul>
 *
 * <p>Here is a snippet showing the necessary elements in the
 * <a href="{@docRoot}guide/topics/manifest/manifest-intro.html">manifest</a> entry for your searchable activity.
 * <pre class="prettyprint">
 *        &lt;!-- Search Activity - searchable --&gt;
 *        &lt;activity android:name="MySearchActivity"
 *                  android:label="Search"
 *                  android:launchMode="singleTop"&gt;
 *            &lt;intent-filter&gt;
 *                &lt;action android:name="android.intent.action.SEARCH" /&gt;
 *                &lt;category android:name="android.intent.category.DEFAULT" /&gt;
 *            &lt;/intent-filter&gt;
 *            &lt;meta-data android:name="android.app.searchable"
 *                       android:resource="@xml/searchable" /&gt;
 *        &lt;/activity&gt;</pre>
 *
 * <p>Next, you must provide the rest of the searchability configuration in
 * the small XML file, stored in the ../xml/ folder in your build.  The XML file is a
 * simple enumeration of the search configuration parameters for searching within this activity,
 * application, or package.  Here is a sample XML file (named searchable.xml, for use with
 * the above manifest) for a query-search activity.
 *
 * <pre class="prettyprint">
 * &lt;searchable xmlns:android="http://schemas.android.com/apk/res/android"
 *     android:label="@string/search_label"
 *     android:hint="@string/search_hint" &gt;
 * &lt;/searchable&gt;</pre>
 *
 * <p>Note that all user-visible strings <i>must</i> be provided in the form of "@string"
 * references.  Hard-coded strings, which cannot be localized, will not work properly in search
 * metadata.
 *
 * <p>Attributes you can set in search metadata:
 * <table border="2" width="85%" align="center" frame="hsides" rules="rows">
 *
 *     <thead>
 *     <tr><th>Attribute</th> <th>Description</th> <th>Required?</th></tr>
 *     </thead>
 *
 *     <tbody>
 *     <tr><th>android:label</th>
 *         <td>This is the name for your application that will be presented to the user in a
 *             list of search targets, or in the search box as a label.</td>
 *         <td align="center">Yes</td>
 *     </tr>
 *
 *     <tr><th>android:icon</th>
 *         <td><strong>This is deprecated.</strong><br/>The default
 *           application icon is now always used, so this attribute is
 *           obsolete.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:hint</th>
 *         <td>This is the text to display in the search text field when no text
 *             has been entered by the user.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:searchMode</th>
 *         <td>If provided and non-zero, sets additional modes for control of the search
 *             presentation.  The following mode bits are defined:
 *             <table border="2" align="center" frame="hsides" rules="rows">
 *                 <tbody>
 *                 <tr><th>showSearchLabelAsBadge</th>
 *                     <td>If set, this flag enables the display of the search target (label)
 *                         above the search box. As an alternative, you may
 *                         want to instead use "hint" text in the search box.
 *                         See the "android:hint" attribute above.</td>
 *                 </tr>
 *                 <tr><th>showSearchIconAsBadge</th>
 *                     <td><strong>This is deprecated.</strong><br/>The default
 *                         application icon is now always used, so this
 *                         option is obsolete.</td>
 *                 </tr>
 *                 <tr><th>queryRewriteFromData</th>
 *                     <td>If set, this flag causes the suggestion column SUGGEST_COLUMN_INTENT_DATA
 *                         to be considered as the text for suggestion query rewriting.  This should
 *                         only be used when the values in SUGGEST_COLUMN_INTENT_DATA are suitable
 *                         for user inspection and editing - typically, HTTP/HTTPS Uri's.</td>
 *                 </tr>
 *                 <tr><th>queryRewriteFromText</th>
 *                     <td>If set, this flag causes the suggestion column SUGGEST_COLUMN_TEXT_1 to
 *                         be considered as the text for suggestion query rewriting.  This should
 *                         be used for suggestions in which no query text is provided and the
 *                         SUGGEST_COLUMN_INTENT_DATA values are not suitable for user inspection
 *                         and editing.</td>
 *                 </tr>
 *                 </tbody>
 *            </table>
 *            Note that the icon of your app will likely be shown alongside any badge you specify,
 *            to differentiate search in your app from Quick Search Box. The display of this icon
 *            is not under the app's control.
 *         </td>
 *
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:inputType</th>
 *         <td>If provided, supplies a hint about the type of search text the user will be
 *             entering.  For most searches, in which free form text is expected, this attribute
 *             need not be provided.  Suitable values for this attribute are described in the
 *             <a href="../R.attr.html#inputType">inputType</a> attribute.</td>
 *         <td align="center">No</td>
 *     </tr>
 *     <tr><th>android:imeOptions</th>
 *         <td>If provided, supplies additional options for the input method.
 *             For most searches, in which free form text is expected, this attribute
 *             need not be provided, and will default to "actionSearch".
 *             Suitable values for this attribute are described in the
 *             <a href="../R.attr.html#imeOptions">imeOptions</a> attribute.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     </tbody>
 * </table>
 *
 * <p><b>Styleable Resources in your Metadata.</b>  It's possible to provide alternate strings
 * for your searchable application, in order to provide localization and/or to better visual
 * presentation on different device configurations.  Each searchable activity has a single XML
 * metadata file, but any resource references can be replaced at runtime based on device
 * configuration, language setting, and other system inputs.
 *
 * <p>A concrete example is the "hint" text you supply using the android:searchHint attribute.
 * In portrait mode you'll have less screen space and may need to provide a shorter string, but
 * in landscape mode you can provide a longer, more descriptive hint.  To do this, you'll need to
 * define two or more strings.xml files, in the following directories:
 * <ul><li>.../res/values-land/strings.xml</li>
 * <li>.../res/values-port/strings.xml</li>
 * <li>.../res/values/strings.xml</li></ul>
 *
 * <p>For more complete documentation on this capability, see
 * <a href="{@docRoot}guide/topics/resources/resources-i18n.html#AlternateResources">Resources and
 * Internationalization: Alternate Resources</a>.
 *
 * <p><b>Metadata for non-searchable activities.</b>  Activities which are part of a searchable
 * application, but don't implement search itself, require a bit of "glue" in order to cause
 * them to invoke search using your searchable activity as their primary context.  If this is not
 * provided, then searches from these activities will use the system default search context.
 *
 * <p>The simplest way to specify this is to add a <i>search reference</i> element to the
 * application entry in the <a href="{@docRoot}guide/topics/manifest/manifest-intro.html">manifest</a> file.
 * The value of this reference can be either of:
 * <ul><li>The name of your searchable activity.
 * It is typically prefixed by '.' to indicate that it's in the same package.</li>
 * <li>A "*" indicates that the system may select a default searchable activity, in which
 * case it will typically select web-based search.</li>
 * </ul>
 *
 * <p>Here is a snippet showing the necessary addition to the manifest entry for your
 * non-searchable activities.
 * <pre class="prettyprint">
 *        &lt;application&gt;
 *            &lt;meta-data android:name="android.app.default_searchable"
 *                       android:value=".MySearchActivity" /&gt;
 *
 *            &lt;!-- followed by activities, providers, etc... --&gt;
 *        &lt;/application&gt;</pre>
 *
 * <p>You can also specify android.app.default_searchable on a per-activity basis, by including
 * the meta-data element (as shown above) in one or more activity sections.  If found, these will
 * override the reference in the application section.  The only reason to configure your application
 * this way would be if you wish to partition it into separate sections with different search
 * behaviors;  Otherwise this configuration is not recommended.
 *
 * <p><b>Additional metadata for search suggestions.</b>  If you have defined a content provider
 * to generate search suggestions, you'll need to publish it to the system, and you'll need to
 * provide a bit of additional XML metadata in order to configure communications with it.
 *
 * <p>First, in your <a href="{@docRoot}guide/topics/manifest/manifest-intro.html">manifest</a>, you'll add the
 * following lines.
 * <pre class="prettyprint">
 *        &lt;!-- Content provider for search suggestions --&gt;
 *        &lt;provider android:name="YourSuggestionProviderClass"
 *                android:authorities="your.suggestion.authority" /&gt;</pre>
 *
 * <p>Next, you'll add a few lines to your XML metadata file, as shown:
 * <pre class="prettyprint">
 *     &lt;!-- Required attribute for any suggestions provider --&gt;
 *     android:searchSuggestAuthority="your.suggestion.authority"
 *
 *     &lt;!-- Optional attribute for configuring queries --&gt;
 *     android:searchSuggestSelection="field =?"
 *
 *     &lt;!-- Optional attributes for configuring intent construction --&gt;
 *     android:searchSuggestIntentAction="intent action string"
 *     android:searchSuggestIntentData="intent data Uri" /&gt;</pre>
 *
 * <p>Elements of search metadata that support suggestions:
 * <table border="2" width="85%" align="center" frame="hsides" rules="rows">
 *
 *     <thead>
 *     <tr><th>Attribute</th> <th>Description</th> <th>Required?</th></tr>
 *     </thead>
 *
 *     <tbody>
 *     <tr><th>android:searchSuggestAuthority</th>
 *         <td>This value must match the authority string provided in the <i>provider</i> section
 *             of your <a href="{@docRoot}guide/topics/manifest/manifest-intro.html">manifest</a>.</td>
 *         <td align="center">Yes</td>
 *     </tr>
 *
 *     <tr><th>android:searchSuggestPath</th>
 *         <td>If provided, this will be inserted in the suggestions query Uri, after the authority
 *             you have provide but before the standard suggestions path.  This is only required if
 *             you have a single content provider issuing different types of suggestions (e.g. for
 *             different data types) and you need a way to disambiguate the suggestions queries
 *             when they are received.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:searchSuggestSelection</th>
 *         <td>If provided, this value will be passed into your query function as the
 *             <i>selection</i> parameter.  Typically this will be a WHERE clause for your database,
 *             and will contain a single question mark, which represents the actual query string
 *             that has been typed by the user.  However, you can also use any non-null value
 *             to simply trigger the delivery of the query text (via selection arguments), and then
 *             use the query text in any way appropriate for your provider (ignoring the actual
 *             text of the selection parameter.)</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:searchSuggestIntentAction</th>
 *         <td>If provided, and not overridden by the selected suggestion, this value will be
 *             placed in the action field of the {@link android.content.Intent Intent} when the
 *             user clicks a suggestion.</td>
 *         <td align="center">No</td>
 *
 *     <tr><th>android:searchSuggestIntentData</th>
 *         <td>If provided, and not overridden by the selected suggestion, this value will be
 *             placed in the data field of the {@link android.content.Intent Intent} when the user
 *             clicks a suggestion.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     </tbody>
 * </table>
 *
 * <p>Elements of search metadata that configure search suggestions being available to Quick Search
 * Box:
 * <table border="2" width="85%" align="center" frame="hsides" rules="rows">
 *
 *     <thead>
 *     <tr><th>Attribute</th> <th>Description</th> <th>Required?</th></tr>
 *     </thead>
 *
 *     <tr><th>android:includeInGlobalSearch</th>
 *         <td>If true, indicates the search suggestions provided by your application should be
 *             included in the globally accessible Quick Search Box.  The attributes below are only
 *             applicable if this is set to true.</td>
 *         <td align="center">Yes</td>
 *     </tr>
 *
 *     <tr><th>android:searchSettingsDescription</th>
 *         <td>If provided, provides a brief description of the search suggestions that are provided
 *             by your application to Quick Search Box, and will be displayed in the search settings
 *             entry for your application.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:queryAfterZeroResults</th>
 *         <td>Indicates whether a source should be invoked for supersets of queries it has
 *             returned zero results for in the past.  For example, if a source returned zero
 *             results for "bo", it would be ignored for "bob".  If set to false, this source
 *             will only be ignored for a single session; the next time the search dialog is
 *             invoked, all sources will be queried.  The default value is false.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:searchSuggestThreshold</th>
 *         <td>Indicates the minimum number of characters needed to trigger a source from Quick
 *             Search Box.  Only guarantees that a source will not be queried for anything shorter
 *             than the threshold.  The default value is 0.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     </tbody>
 * </table>
 *
 * <p><b>Additional metadata for search action keys.</b>  For each action key that you would like to
 * define, you'll need to add an additional element defining that key, and using the attributes
 * discussed in <a href="#ActionKeys">Action Keys</a>.  A simple example is shown here:
 *
 * <pre class="prettyprint">&lt;actionkey
 *     android:keycode="KEYCODE_CALL"
 *     android:queryActionMsg="call"
 *     android:suggestActionMsg="call"
 *     android:suggestActionMsgColumn="call_column" /&gt;</pre>
 *
 * <p>Elements of search metadata that support search action keys.  Note that although each of the
 * action message elements are marked as <i>optional</i>, at least one must be present for the
 * action key to have any effect.
 *
 * <table border="2" width="85%" align="center" frame="hsides" rules="rows">
 *
 *     <thead>
 *     <tr><th>Attribute</th> <th>Description</th> <th>Required?</th></tr>
 *     </thead>
 *
 *     <tbody>
 *     <tr><th>android:keycode</th>
 *         <td>This attribute denotes the action key you wish to respond to.  Note that not
 *             all action keys are actually supported using this mechanism, as many of them are
 *             used for typing, navigation, or system functions.  This will be added to the
 *             {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} intent that is passed to
 *             your searchable activity.  To examine the key code, use
 *             {@link android.content.Intent#getIntExtra getIntExtra(SearchManager.ACTION_KEY)}.
 *             <p>Note, in addition to the keycode, you must also provide one or more of the action
 *             specifier attributes.</td>
 *         <td align="center">Yes</td>
 *     </tr>
 *
 *     <tr><th>android:queryActionMsg</th>
 *         <td>If you wish to handle an action key during normal search query entry, you
 *          must define an action string here.  This will be added to the
 *          {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} intent that is passed to your
 *          searchable activity.  To examine the string, use
 *          {@link android.content.Intent#getStringExtra
 *          getStringExtra(SearchManager.ACTION_MSG)}.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:suggestActionMsg</th>
 *         <td>If you wish to handle an action key while a suggestion is being displayed <i>and
 *             selected</i>, there are two ways to handle this.  If <i>all</i> of your suggestions
 *             can handle the action key, you can simply define the action message using this
 *             attribute.  This will be added to the
 *             {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} intent that is passed to
 *             your searchable activity.  To examine the string, use
 *             {@link android.content.Intent#getStringExtra
 *             getStringExtra(SearchManager.ACTION_MSG)}.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:suggestActionMsgColumn</th>
 *         <td>If you wish to handle an action key while a suggestion is being displayed <i>and
 *             selected</i>, but you do not wish to enable this action key for every suggestion,
 *             then you can use this attribute to control it on a suggestion-by-suggestion basis.
 *             First, you must define a column (and name it here) where your suggestions will
 *             include the action string.  Then, in your content provider, you must provide this
 *             column, and when desired, provide data in this column.
 *             The search manager will look at your suggestion cursor, using the string
 *             provided here in order to select a column, and will use that to select a string from
 *             the cursor.  That string will be added to the
 *             {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} intent that is passed to
 *             your searchable activity.  To examine the string, use
 *             {@link android.content.Intent#getStringExtra
 *             getStringExtra(SearchManager.ACTION_MSG)}.  <i>If the data does not exist for the
 *             selection suggestion, the action key will be ignored.</i></td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     </tbody>
 * </table>
 *
 * <p><b>Additional metadata for enabling voice search.</b>  To enable voice search for your
 * activity, you can add fields to the metadata that enable and configure voice search.  When
 * enabled (and available on the device), a voice search button will be displayed in the
 * Search UI.  Clicking this button will launch a voice search activity.  When the user has
 * finished speaking, the voice search phrase will be transcribed into text and presented to the
 * searchable activity as if it were a typed query.
 *
 * <p>Elements of search metadata that support voice search:
 * <table border="2" width="85%" align="center" frame="hsides" rules="rows">
 *
 *     <thead>
 *     <tr><th>Attribute</th> <th>Description</th> <th>Required?</th></tr>
 *     </thead>
 *
 *     <tr><th>android:voiceSearchMode</th>
 *         <td>If provided and non-zero, enables voice search.  (Voice search may not be
 *             provided by the device, in which case these flags will have no effect.)  The
 *             following mode bits are defined:
 *             <table border="2" align="center" frame="hsides" rules="rows">
 *                 <tbody>
 *                 <tr><th>showVoiceSearchButton</th>
 *                     <td>If set, display a voice search button.  This only takes effect if voice
 *                         search is available on the device.  If set, then launchWebSearch or
 *                         launchRecognizer must also be set.</td>
 *                 </tr>
 *                 <tr><th>launchWebSearch</th>
 *                     <td>If set, the voice search button will take the user directly to a
 *                         built-in voice web search activity.  Most applications will not use this
 *                         flag, as it will take the user away from the activity in which search
 *                         was invoked.</td>
 *                 </tr>
 *                 <tr><th>launchRecognizer</th>
 *                     <td>If set, the voice search button will take the user directly to a
 *                         built-in voice recording activity.  This activity will prompt the user
 *                         to speak, transcribe the spoken text, and forward the resulting query
 *                         text to the searchable activity, just as if the user had typed it into
 *                         the search UI and clicked the search button.</td>
 *                 </tr>
 *                 </tbody>
 *            </table></td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:voiceLanguageModel</th>
 *         <td>If provided, this specifies the language model that should be used by the voice
 *             recognition system.
 *             See {@link android.speech.RecognizerIntent#EXTRA_LANGUAGE_MODEL}
 *             for more information.  If not provided, the default value
 *             {@link android.speech.RecognizerIntent#LANGUAGE_MODEL_FREE_FORM} will be used.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:voicePromptText</th>
 *         <td>If provided, this specifies a prompt that will be displayed during voice input.
 *             (If not provided, a default prompt will be displayed.)</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:voiceLanguage</th>
 *         <td>If provided, this specifies the spoken language to be expected.  This is only
 *             needed if it is different from the current value of
 *             {@link java.util.Locale#getDefault()}.
 *             </td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     <tr><th>android:voiceMaxResults</th>
 *         <td>If provided, enforces the maximum number of results to return, including the "best"
 *             result which will always be provided as the SEARCH intent's primary query.  Must be
 *             one or greater.  Use {@link android.speech.RecognizerIntent#EXTRA_RESULTS}
 *             to get the results from the intent.  If not provided, the recognizer will choose
 *             how many results to return.</td>
 *         <td align="center">No</td>
 *     </tr>
 *
 *     </tbody>
 * </table>
 *
 * <a name="PassingSearchContext"></a>
 * <h3>Passing Search Context</h3>
 *
 * <p>In order to improve search experience, an application may wish to specify
 * additional data along with the search, such as local history or context.  For
 * example, a maps search would be improved by including the current location.
 * In order to simplify the structure of your activities, this can be done using
 * the search manager.
 *
 * <p>Any data can be provided at the time the search is launched, as long as it
 * can be stored in a {@link android.os.Bundle Bundle} object.
 *
 * <p>To pass application data into the Search Manager, you'll need to override
 * {@link android.app.Activity#onSearchRequested onSearchRequested} as follows:
 *
 * <pre class="prettyprint">
 * &#64;Override
 * public boolean onSearchRequested() {
 *     Bundle appData = new Bundle();
 *     appData.put...();
 *     appData.put...();
 *     startSearch(null, false, appData, false);
 *     return true;
 * }</pre>
 *
 * <p>To receive application data from the Search Manager, you'll extract it from
 * the {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH}
 * {@link android.content.Intent Intent} as follows:
 *
 * <pre class="prettyprint">
 * final Bundle appData = queryIntent.getBundleExtra(SearchManager.APP_DATA);
 * if (appData != null) {
 *     appData.get...();
 *     appData.get...();
 * }</pre>
 *
 * <a name="ProtectingUserPrivacy"></a>
 * <h3>Protecting User Privacy</h3>
 *
 * <p>Many users consider their activities on the phone, including searches, to be private
 * information.  Applications that implement search should take steps to protect users' privacy
 * wherever possible.  This section covers two areas of concern, but you should consider your search
 * design carefully and take any additional steps necessary.
 *
 * <p><b>Don't send personal information to servers, and if you do, don't log it.</b>
 * "Personal information" is information that can personally identify your users, such as name,
 * email address or billing information, or other data which can be reasonably linked to such
 * information.  If your application implements search with the assistance of a server, try to
 * avoid sending personal information with your searches.  For example, if you are searching for
 * businesses near a zip code, you don't need to send the user ID as well - just send the zip code
 * to the server.  If you do need to send personal information, you should take steps to avoid
 * logging it.  If you must log it, you should protect that data very carefully, and erase it as
 * soon as possible.
 *
 * <p><b>Provide the user with a way to clear their search history.</b>  The Search Manager helps
 * your application provide context-specific suggestions.  Sometimes these suggestions are based
 * on previous searches, or other actions taken by the user in an earlier session.  A user may not
 * wish for previous searches to be revealed to other users, for instance if they share their phone
 * with a friend.  If your application provides suggestions that can reveal previous activities,
 * you should implement a "Clear History" menu, preference, or button.  If you are using
 * {@link android.provider.SearchRecentSuggestions}, you can simply call its
 * {@link android.provider.SearchRecentSuggestions#clearHistory() clearHistory()} method from
 * your "Clear History" UI.  If you are implementing your own form of recent suggestions, you'll
 * need to provide a similar a "clear history" API in your provider, and call it from your
 * "Clear History" UI.
 */
public class SearchManager
        implements DialogInterface.OnDismissListener, DialogInterface.OnCancelListener
{

    private static final boolean DBG = false;
    private static final String TAG = "SearchManager";

    /**
     * This is a shortcut definition for the default menu key to use for invoking search.
     *
     * See Menu.Item.setAlphabeticShortcut() for more information.
     */
    public final static char MENU_KEY = 's';

    /**
     * This is a shortcut definition for the default menu key to use for invoking search.
     *
     * See Menu.Item.setAlphabeticShortcut() for more information.
     */
    public final static int MENU_KEYCODE = KeyEvent.KEYCODE_S;

    /**
     * Intent extra data key: Use this key with
     * {@link android.content.Intent#getStringExtra
     *  content.Intent.getStringExtra()}
     * to obtain the query string from Intent.ACTION_SEARCH.
     */
    public final static String QUERY = "query";

    /**
     * Intent extra data key: Use this key with
     * {@link android.content.Intent#getStringExtra
     *  content.Intent.getStringExtra()}
     * to obtain the query string typed in by the user.
     * This may be different from the value of {@link #QUERY}
     * if the intent is the result of selecting a suggestion.
     * In that case, {@link #QUERY} will contain the value of
     * {@link #SUGGEST_COLUMN_QUERY} for the suggestion, and
     * {@link #USER_QUERY} will contain the string typed by the
     * user.
     */
    public final static String USER_QUERY = "user_query";

    /**
     * Intent extra data key: Use this key with Intent.ACTION_SEARCH and
     * {@link android.content.Intent#getBundleExtra
     *  content.Intent.getBundleExtra()}
     * to obtain any additional app-specific data that was inserted by the
     * activity that launched the search.
     */
    public final static String APP_DATA = "app_data";

    /**
     * Intent app_data bundle key: Use this key with the bundle from
     * {@link android.content.Intent#getBundleExtra
     * content.Intent.getBundleExtra(APP_DATA)} to obtain the source identifier
     * set by the activity that launched the search.
     *
     * @hide
     */
    public final static String SOURCE = "source";

    /**
     * Intent extra data key: Use {@link android.content.Intent#getBundleExtra
     * content.Intent.getBundleExtra(SEARCH_MODE)} to get the search mode used
     * to launch the intent.
     * The only current value for this is {@link #MODE_GLOBAL_SEARCH_SUGGESTION}.
     *
     * @hide
     */
    public final static String SEARCH_MODE = "search_mode";

    /**
     * Value for the {@link #SEARCH_MODE} key.
     * This is used if the intent was launched by clicking a suggestion in global search
     * mode (Quick Search Box).
     *
     * @hide
     */
    public static final String MODE_GLOBAL_SEARCH_SUGGESTION = "global_search_suggestion";

    /**
     * Intent extra data key: Use this key with Intent.ACTION_SEARCH and
     * {@link android.content.Intent#getIntExtra content.Intent.getIntExtra()}
     * to obtain the keycode that the user used to trigger this query.  It will be zero if the
     * user simply pressed the "GO" button on the search UI.  This is primarily used in conjunction
     * with the keycode attribute in the actionkey element of your searchable.xml configuration
     * file.
     */
    public final static String ACTION_KEY = "action_key";

    /**
     * Intent component name key: This key will be used for the extra populated by the
     * {@link #SUGGEST_COLUMN_INTENT_COMPONENT_NAME} column.
     *
     * {@hide}
     */
    public final static String COMPONENT_NAME_KEY = "intent_component_name_key";

    /**
     * Intent extra data key: This key will be used for the extra populated by the
     * {@link #SUGGEST_COLUMN_INTENT_EXTRA_DATA} column.
     */
    public final static String EXTRA_DATA_KEY = "intent_extra_data_key";

    /**
     * Defines the constants used in the communication between {@link android.app.SearchDialog} and
     * the global search provider via {@link Cursor#respond(android.os.Bundle)}.
     *
     * @hide
     */
    public static class DialogCursorProtocol {

        /**
         * The sent bundle will contain this integer key, with a value set to one of the events
         * below.
         */
        public final static String METHOD = "DialogCursorProtocol.method";

        /**
         * After data has been refreshed.
         */
        public final static int POST_REFRESH = 0;
        public final static String POST_REFRESH_RECEIVE_ISPENDING
                = "DialogCursorProtocol.POST_REFRESH.isPending";
        public final static String POST_REFRESH_RECEIVE_DISPLAY_NOTIFY
                = "DialogCursorProtocol.POST_REFRESH.displayNotify";

        /**
         * When a position has been clicked.
         */
        public final static int CLICK = 2;
        public final static String CLICK_SEND_POSITION
                = "DialogCursorProtocol.CLICK.sendPosition";
        public final static String CLICK_SEND_MAX_DISPLAY_POS
                = "DialogCursorProtocol.CLICK.sendDisplayPosition";
        public final static String CLICK_SEND_ACTION_KEY
                = "DialogCursorProtocol.CLICK.sendActionKey";
        public final static String CLICK_SEND_ACTION_MSG
                = "DialogCursorProtocol.CLICK.sendActionMsg";
        public final static String CLICK_RECEIVE_SELECTED_POS
                = "DialogCursorProtocol.CLICK.receiveSelectedPosition";

        /**
         * When the threshold received in {@link #POST_REFRESH_RECEIVE_DISPLAY_NOTIFY} is displayed.
         */
        public final static int THRESH_HIT = 3;

        /**
         * When a search is started without using a suggestion.
         */
        public final static int SEARCH = 4;
        public final static String SEARCH_SEND_MAX_DISPLAY_POS
                = "DialogCursorProtocol.SEARCH.sendDisplayPosition";
        public final static String SEARCH_SEND_QUERY = "DialogCursorProtocol.SEARCH.query";
    }

    /**
     * Intent extra data key: Use this key with Intent.ACTION_SEARCH and
     * {@link android.content.Intent#getStringExtra content.Intent.getStringExtra()}
     * to obtain the action message that was defined for a particular search action key and/or
     * suggestion.  It will be null if the search was launched by typing "enter", touched the the
     * "GO" button, or other means not involving any action key.
     */
    public final static String ACTION_MSG = "action_msg";

    /**
     * Uri path for queried suggestions data.  This is the path that the search manager
     * will use when querying your content provider for suggestions data based on user input
     * (e.g. looking for partial matches).
     * Typically you'll use this with a URI matcher.
     */
    public final static String SUGGEST_URI_PATH_QUERY = "search_suggest_query";

    /**
     * MIME type for suggestions data.  You'll use this in your suggestions content provider
     * in the getType() function.
     */
    public final static String SUGGEST_MIME_TYPE =
            "vnd.android.cursor.dir/vnd.android.search.suggest";

    /**
     * Uri path for shortcut validation.  This is the path that the search manager will use when
     * querying your content provider to refresh a shortcutted suggestion result and to check if it
     * is still valid.  When asked, a source may return an up to date result, or no result.  No
     * result indicates the shortcut refers to a no longer valid sugggestion.
     *
     * @see #SUGGEST_COLUMN_SHORTCUT_ID
     */
    public final static String SUGGEST_URI_PATH_SHORTCUT = "search_suggest_shortcut";

    /**
     * MIME type for shortcut validation.  You'll use this in your suggestions content provider
     * in the getType() function.
     */
    public final static String SHORTCUT_MIME_TYPE =
            "vnd.android.cursor.item/vnd.android.search.suggest";


    /**
     * The authority of the provider to report clicks to when a click is detected after pivoting
     * into a specific app's search from global search.
     *
     * In addition to the columns below, the suggestion columns are used to pass along the full
     * suggestion so it can be shortcutted.
     *
     * @hide
     */
    public final static String SEARCH_CLICK_REPORT_AUTHORITY =
            "com.android.globalsearch.stats";

    /**
     * The path the write goes to.
     *
     * @hide
     */
    public final static String SEARCH_CLICK_REPORT_URI_PATH = "click";

    /**
     * The column storing the query for the click.
     *
     * @hide
     */
    public final static String SEARCH_CLICK_REPORT_COLUMN_QUERY = "query";

    /**
     * The column storing the component name of the application that was pivoted into.
     *
     * @hide
     */
    public final static String SEARCH_CLICK_REPORT_COLUMN_COMPONENT = "component";

    /**
     * Column name for suggestions cursor.  <i>Unused - can be null or column can be omitted.</i>
     */
    public final static String SUGGEST_COLUMN_FORMAT = "suggest_format";
    /**
     * Column name for suggestions cursor.  <i>Required.</i>  This is the primary line of text that
     * will be presented to the user as the suggestion.
     */
    public final static String SUGGEST_COLUMN_TEXT_1 = "suggest_text_1";
    /**
     * Column name for suggestions cursor.  <i>Optional.</i>  If your cursor includes this column,
     *  then all suggestions will be provided in a two-line format.  The second line of text is in
     *  a much smaller appearance.
     */
    public final static String SUGGEST_COLUMN_TEXT_2 = "suggest_text_2";
    /**
     * Column name for suggestions cursor.  <i>Optional.</i>  If your cursor includes this column,
     *  then all suggestions will be provided in a format that includes space for two small icons,
     *  one at the left and one at the right of each suggestion.  The data in the column must
     *  be a resource ID of a drawable, or a URI in one of the following formats:
     *
     * <ul>
     * <li>content ({@link android.content.ContentResolver#SCHEME_CONTENT})</li>
     * <li>android.resource ({@link android.content.ContentResolver#SCHEME_ANDROID_RESOURCE})</li>
     * <li>file ({@link android.content.ContentResolver#SCHEME_FILE})</li>
     * </ul>
     *
     * See {@link android.content.ContentResolver#openAssetFileDescriptor(Uri, String)}
     * for more information on these schemes.
     */
    public final static String SUGGEST_COLUMN_ICON_1 = "suggest_icon_1";
    /**
     * Column name for suggestions cursor.  <i>Optional.</i>  If your cursor includes this column,
     *  then all suggestions will be provided in a format that includes space for two small icons,
     *  one at the left and one at the right of each suggestion.  The data in the column must
     *  be a resource ID of a drawable, or a URI in one of the following formats:
     *
     * <ul>
     * <li>content ({@link android.content.ContentResolver#SCHEME_CONTENT})</li>
     * <li>android.resource ({@link android.content.ContentResolver#SCHEME_ANDROID_RESOURCE})</li>
     * <li>file ({@link android.content.ContentResolver#SCHEME_FILE})</li>
     * </ul>
     *
     * See {@link android.content.ContentResolver#openAssetFileDescriptor(Uri, String)}
     * for more information on these schemes.
     */
    public final static String SUGGEST_COLUMN_ICON_2 = "suggest_icon_2";
    /**
     * Column name for suggestions cursor.  <i>Optional.</i>  If this column exists <i>and</i>
     * this element exists at the given row, this is the action that will be used when
     * forming the suggestion's intent.  If the element is not provided, the action will be taken
     * from the android:searchSuggestIntentAction field in your XML metadata.  <i>At least one of
     * these must be present for the suggestion to generate an intent.</i>  Note:  If your action is
     * the same for all suggestions, it is more efficient to specify it using XML metadata and omit
     * it from the cursor.
     */
    public final static String SUGGEST_COLUMN_INTENT_ACTION = "suggest_intent_action";
    /**
     * Column name for suggestions cursor.  <i>Optional.</i>  If this column exists <i>and</i>
     * this element exists at the given row, this is the data that will be used when
     * forming the suggestion's intent.  If the element is not provided, the data will be taken
     * from the android:searchSuggestIntentData field in your XML metadata.  If neither source
     * is provided, the Intent's data field will be null.  Note:  If your data is
     * the same for all suggestions, or can be described using a constant part and a specific ID,
     * it is more efficient to specify it using XML metadata and omit it from the cursor.
     */
    public final static String SUGGEST_COLUMN_INTENT_DATA = "suggest_intent_data";
    /**
     * Column name for suggestions cursor.  <i>Optional.</i>  If this column exists <i>and</i>
     * this element exists at the given row, this is the data that will be used when
     * forming the suggestion's intent. If not provided, the Intent's extra data field will be null.
     * This column allows suggestions to provide additional arbitrary data which will be included as
     * an extra under the key {@link #EXTRA_DATA_KEY}.
     */
    public final static String SUGGEST_COLUMN_INTENT_EXTRA_DATA = "suggest_intent_extra_data";
    /**
     * Column name for suggestions cursor.  <i>Optional.</i>  This column allows suggestions
     *  to provide additional arbitrary data which will be included as an extra under the key
     *  {@link #COMPONENT_NAME_KEY}. For use by the global search system only - if other providers
     *  attempt to use this column, the value will be overwritten by global search.
     *
     * @hide
     */
    public final static String SUGGEST_COLUMN_INTENT_COMPONENT_NAME = "suggest_intent_component";
    /**
     * Column name for suggestions cursor.  <i>Optional.</i>  If this column exists <i>and</i>
     * this element exists at the given row, then "/" and this value will be appended to the data
     * field in the Intent.  This should only be used if the data field has already been set to an
     * appropriate base string.
     */
    public final static String SUGGEST_COLUMN_INTENT_DATA_ID = "suggest_intent_data_id";
    /**
     * Column name for suggestions cursor.  <i>Required if action is
     * {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH}, optional otherwise.</i>  If this
     * column exists <i>and</i> this element exists at the given row, this is the data that will be
     * used when forming the suggestion's query.
     */
    public final static String SUGGEST_COLUMN_QUERY = "suggest_intent_query";

    /**
     * Column name for suggestions cursor. <i>Optional.</i>  This column is used to indicate whether
     * a search suggestion should be stored as a shortcut, and whether it should be refreshed.  If
     * missing, the result will be stored as a shortcut and never validated.  If set to
     * {@link #SUGGEST_NEVER_MAKE_SHORTCUT}, the result will not be stored as a shortcut.
     * Otherwise, the shortcut id will be used to check back for an up to date suggestion using
     * {@link #SUGGEST_URI_PATH_SHORTCUT}.
     */
    public final static String SUGGEST_COLUMN_SHORTCUT_ID = "suggest_shortcut_id";

    /**
     * Column name for suggestions cursor. <i>Optional.</i>  This column is used to specify the
     * cursor item's background color if it needs a non-default background color. A non-zero value
     * indicates a valid background color to override the default.
     *
     * @hide For internal use, not part of the public API.
     */
    public final static String SUGGEST_COLUMN_BACKGROUND_COLOR = "suggest_background_color";

    /**
     * Column name for suggestions cursor. <i>Optional.</i> This column is used to specify
     * that a spinner should be shown in lieu of an icon2 while the shortcut of this suggestion
     * is being refreshed.
     */
    public final static String SUGGEST_COLUMN_SPINNER_WHILE_REFRESHING =
            "suggest_spinner_while_refreshing";

    /**
     * Column value for suggestion column {@link #SUGGEST_COLUMN_SHORTCUT_ID} when a suggestion
     * should not be stored as a shortcut in global search.
     */
    public final static String SUGGEST_NEVER_MAKE_SHORTCUT = "_-1";

    /**
     * Query parameter added to suggestion queries to limit the number of suggestions returned.
     * This limit is only advisory and suggestion providers may chose to ignore it.
     */
    public final static String SUGGEST_PARAMETER_LIMIT = "limit";

    /**
     * If a suggestion has this value in {@link #SUGGEST_COLUMN_INTENT_ACTION},
     * the search dialog will switch to a different suggestion source when the
     * suggestion is clicked.
     *
     * {@link #SUGGEST_COLUMN_INTENT_DATA} must contain
     * the flattened {@link ComponentName} of the activity which is to be searched.
     *
     * TODO: Should {@link #SUGGEST_COLUMN_INTENT_DATA} instead contain a URI in the format
     * used by {@link android.provider.Applications}?
     *
     * TODO: This intent should be protected by the same permission that we use
     * for replacing the global search provider.
     *
     * The query text field will be set to the value of {@link #SUGGEST_COLUMN_QUERY}.
     *
     * @hide Pending API council approval.
     */
    public final static String INTENT_ACTION_CHANGE_SEARCH_SOURCE
            = "android.search.action.CHANGE_SEARCH_SOURCE";

    /**
     * Intent action for finding the global search activity.
     * The global search provider should handle this intent.
     *
     * @hide Pending API council approval.
     */
    public final static String INTENT_ACTION_GLOBAL_SEARCH
            = "android.search.action.GLOBAL_SEARCH";

    /**
     * Intent action for starting the global search settings activity.
     * The global search provider should handle this intent.
     *
     * @hide Pending API council approval.
     */
    public final static String INTENT_ACTION_SEARCH_SETTINGS
            = "android.search.action.SEARCH_SETTINGS";

    /**
     * Intent action for starting a web search provider's settings activity.
     * Web search providers should handle this intent if they have provider-specific
     * settings to implement.
     */
    public final static String INTENT_ACTION_WEB_SEARCH_SETTINGS
            = "android.search.action.WEB_SEARCH_SETTINGS";

    /**
     * Intent action broadcasted to inform that the searchables list or default have changed.
     * Components should handle this intent if they cache any searchable data and wish to stay
     * up to date on changes.
     */
    public final static String INTENT_ACTION_SEARCHABLES_CHANGED
            = "android.search.action.SEARCHABLES_CHANGED";

    /**
     * Intent action broadcasted to inform that the search settings have changed in some way.
     * Either searchables have been enabled or disabled, or a different web search provider
     * has been chosen.
     */
    public final static String INTENT_ACTION_SEARCH_SETTINGS_CHANGED
            = "android.search.action.SETTINGS_CHANGED";

    /**
     * If a suggestion has this value in {@link #SUGGEST_COLUMN_INTENT_ACTION},
     * the search dialog will take no action.
     *
     * @hide
     */
    public final static String INTENT_ACTION_NONE = "android.search.action.ZILCH";

    /**
     * Reference to the shared system search service.
     */
    private static ISearchManager mService;

    private final Context mContext;

    /**
     * compact representation of the activity associated with this search manager so
     * we can say who we are when starting search.  the search managerservice, in turn,
     * uses this to properly handle the back stack.
     */
    private int mIdent;

    /**
     * The package associated with this seach manager.
     */
    private String mAssociatedPackage;

    // package private since they are used by the inner class SearchManagerCallback
    /* package */ final Handler mHandler;
    /* package */ OnDismissListener mDismissListener = null;
    /* package */ OnCancelListener mCancelListener = null;

    private final SearchManagerCallback mSearchManagerCallback = new SearchManagerCallback();

    /*package*/ SearchManager(Context context, Handler handler)  {
        mContext = context;
        mHandler = handler;
        mService = ISearchManager.Stub.asInterface(
                ServiceManager.getService(Context.SEARCH_SERVICE));
    }

    /*package*/ boolean hasIdent() {
        return mIdent != 0;
    }

    /*package*/ void setIdent(int ident, ComponentName component) {
        if (mIdent != 0) {
            throw new IllegalStateException("mIdent already set");
        }
        if (component == null) {
            throw new IllegalArgumentException("component must be non-null");
        }
        mIdent = ident;
        mAssociatedPackage = component.getPackageName();
    }

    /**
     * Launch search UI.
     *
     * <p>The search manager will open a search widget in an overlapping
     * window, and the underlying activity may be obscured.  The search
     * entry state will remain in effect until one of the following events:
     * <ul>
     * <li>The user completes the search.  In most cases this will launch
     * a search intent.</li>
     * <li>The user uses the back, home, or other keys to exit the search.</li>
     * <li>The application calls the {@link #stopSearch}
     * method, which will hide the search window and return focus to the
     * activity from which it was launched.</li>
     *
     * <p>Most applications will <i>not</i> use this interface to invoke search.
     * The primary method for invoking search is to call
     * {@link android.app.Activity#onSearchRequested Activity.onSearchRequested()} or
     * {@link android.app.Activity#startSearch Activity.startSearch()}.
     *
     * @param initialQuery A search string can be pre-entered here, but this
     * is typically null or empty.
     * @param selectInitialQuery If true, the intial query will be preselected, which means that
     * any further typing will replace it.  This is useful for cases where an entire pre-formed
     * query is being inserted.  If false, the selection point will be placed at the end of the
     * inserted query.  This is useful when the inserted query is text that the user entered,
     * and the user would expect to be able to keep typing.  <i>This parameter is only meaningful
     * if initialQuery is a non-empty string.</i>
     * @param launchActivity The ComponentName of the activity that has launched this search.
     * @param appSearchData An application can insert application-specific
     * context here, in order to improve quality or specificity of its own
     * searches.  This data will be returned with SEARCH intent(s).  Null if
     * no extra data is required.
     * @param globalSearch If false, this will only launch the search that has been specifically
     * defined by the application (which is usually defined as a local search).  If no default
     * search is defined in the current application or activity, global search will be launched.
     * If true, this will always launch a platform-global (e.g. web-based) search instead.
     *
     * @see android.app.Activity#onSearchRequested
     * @see #stopSearch
     */
    public void startSearch(String initialQuery,
                            boolean selectInitialQuery,
                            ComponentName launchActivity,
                            Bundle appSearchData,
                            boolean globalSearch) {
        if (mIdent == 0) throw new IllegalArgumentException(
                "Called from outside of an Activity context");
        if (!globalSearch && !mAssociatedPackage.equals(launchActivity.getPackageName())) {
            Log.w(TAG, "invoking app search on a different package " +
                    "not associated with this search manager");
        }
        try {
            // activate the search manager and start it up!
            mService.startSearch(initialQuery, selectInitialQuery, launchActivity, appSearchData,
                    globalSearch, mSearchManagerCallback, mIdent);
        } catch (RemoteException ex) {
            Log.e(TAG, "startSearch() failed.", ex);
        }
    }

    /**
     * Similar to {@link #startSearch} but actually fires off the search query after invoking
     * the search dialog.  Made available for testing purposes.
     *
     * @param query The query to trigger.  If empty, request will be ignored.
     * @param launchActivity The ComponentName of the activity that has launched this search.
     * @param appSearchData An application can insert application-specific
     * context here, in order to improve quality or specificity of its own
     * searches.  This data will be returned with SEARCH intent(s).  Null if
     * no extra data is required.
     *
     * @see #startSearch
     */
    public void triggerSearch(String query,
                              ComponentName launchActivity,
                              Bundle appSearchData) {
        if (mIdent == 0) throw new IllegalArgumentException(
                "Called from outside of an Activity context");
        if (!mAssociatedPackage.equals(launchActivity.getPackageName())) {
            throw new IllegalArgumentException("invoking app search on a different package " +
                    "not associated with this search manager");
        }
        if (query == null || TextUtils.getTrimmedLength(query) == 0) {
            Log.w(TAG, "triggerSearch called with empty query, ignoring.");
            return;
        }
        try {
            mService.triggerSearch(query, launchActivity, appSearchData, mSearchManagerCallback,
                    mIdent);
        } catch (RemoteException ex) {
            Log.e(TAG, "triggerSearch() failed.", ex);
        }
    }

    /**
     * Terminate search UI.
     *
     * <p>Typically the user will terminate the search UI by launching a
     * search or by canceling.  This function allows the underlying application
     * or activity to cancel the search prematurely (for any reason).
     *
     * <p>This function can be safely called at any time (even if no search is active.)
     *
     * @see #startSearch
     */
    public void stopSearch() {
        if (DBG) debug("stopSearch()");
        try {
            mService.stopSearch();
        } catch (RemoteException ex) {
        }
    }

    /**
     * Determine if the Search UI is currently displayed.
     *
     * This is provided primarily for application test purposes.
     *
     * @return Returns true if the search UI is currently displayed.
     *
     * @hide
     */
    public boolean isVisible() {
        if (DBG) debug("isVisible()");
        try {
            return mService.isVisible();
        } catch (RemoteException e) {
            Log.e(TAG, "isVisible() failed: " + e);
            return false;
        }
    }

    /**
     * See {@link SearchManager#setOnDismissListener} for configuring your activity to monitor
     * search UI state.
     */
    public interface OnDismissListener {
        /**
         * This method will be called when the search UI is dismissed. To make use of it, you must
         * implement this method in your activity, and call
         * {@link SearchManager#setOnDismissListener} to register it.
         */
        public void onDismiss();
    }

    /**
     * See {@link SearchManager#setOnCancelListener} for configuring your activity to monitor
     * search UI state.
     */
    public interface OnCancelListener {
        /**
         * This method will be called when the search UI is canceled. To make use if it, you must
         * implement this method in your activity, and call
         * {@link SearchManager#setOnCancelListener} to register it.
         */
        public void onCancel();
    }

    /**
     * Set or clear the callback that will be invoked whenever the search UI is dismissed.
     *
     * @param listener The {@link OnDismissListener} to use, or null.
     */
    public void setOnDismissListener(final OnDismissListener listener) {
        mDismissListener = listener;
    }

    /**
     * Set or clear the callback that will be invoked whenever the search UI is canceled.
     *
     * @param listener The {@link OnCancelListener} to use, or null.
     */
    public void setOnCancelListener(OnCancelListener listener) {
        mCancelListener = listener;
    }

    private class SearchManagerCallback extends ISearchManagerCallback.Stub {

        private final Runnable mFireOnDismiss = new Runnable() {
            public void run() {
                if (DBG) debug("mFireOnDismiss");
                if (mDismissListener != null) {
                    mDismissListener.onDismiss();
                }
            }
        };

        private final Runnable mFireOnCancel = new Runnable() {
            public void run() {
                if (DBG) debug("mFireOnCancel");
                if (mCancelListener != null) {
                    mCancelListener.onCancel();
                }
            }
        };

        public void onDismiss() {
            if (DBG) debug("onDismiss()");
            mHandler.post(mFireOnDismiss);
        }

        public void onCancel() {
            if (DBG) debug("onCancel()");
            mHandler.post(mFireOnCancel);
        }

    }

    /**
     * @deprecated This method is an obsolete internal implementation detail. Do not use.
     */
    @Deprecated
    public void onCancel(DialogInterface dialog) {
        throw new UnsupportedOperationException();
    }

    /**
     * @deprecated This method is an obsolete internal implementation detail. Do not use.
     */
    @Deprecated
    public void onDismiss(DialogInterface dialog) {
        throw new UnsupportedOperationException();
    }

    /**
     * Gets information about a searchable activity. This method is static so that it can
     * be used from non-Activity contexts.
     *
     * @param componentName The activity to get searchable information for.
     * @param globalSearch If <code>false</code>, return information about the given activity.
     *        If <code>true</code>, return information about the global search activity.
     * @return Searchable information, or <code>null</code> if the activity is not searchable.
     *
     * @hide because SearchableInfo is not part of the API.
     */
    public SearchableInfo getSearchableInfo(ComponentName componentName,
            boolean globalSearch) {
        try {
            return mService.getSearchableInfo(componentName, globalSearch);
        } catch (RemoteException ex) {
            Log.e(TAG, "getSearchableInfo() failed: " + ex);
            return null;
        }
    }

    /**
     * Checks whether the given searchable is the default searchable.
     *
     * @hide because SearchableInfo is not part of the API.
     */
    public boolean isDefaultSearchable(SearchableInfo searchable) {
        SearchableInfo defaultSearchable = getSearchableInfo(null, true);
        return defaultSearchable != null
                && defaultSearchable.getSearchActivity().equals(searchable.getSearchActivity());
    }

    /**
     * Gets a cursor with search suggestions.
     *
     * @param searchable Information about how to get the suggestions.
     * @param query The search text entered (so far).
     * @return a cursor with suggestions, or <code>null</null> the suggestion query failed.
     *
     * @hide because SearchableInfo is not part of the API.
     */
    public Cursor getSuggestions(SearchableInfo searchable, String query) {
        return getSuggestions(searchable, query, -1);
    }

    /**
     * Gets a cursor with search suggestions.
     *
     * @param searchable Information about how to get the suggestions.
     * @param query The search text entered (so far).
     * @param limit The query limit to pass to the suggestion provider. This is advisory,
     *        the returned cursor may contain more rows. Pass {@code -1} for no limit.
     * @return a cursor with suggestions, or <code>null</null> the suggestion query failed.
     *
     * @hide because SearchableInfo is not part of the API.
     */
    public Cursor getSuggestions(SearchableInfo searchable, String query, int limit) {
        if (searchable == null) {
            return null;
        }

        String authority = searchable.getSuggestAuthority();
        if (authority == null) {
            return null;
        }

        Uri.Builder uriBuilder = new Uri.Builder()
                .scheme(ContentResolver.SCHEME_CONTENT)
                .authority(authority)
                .query("")  // TODO: Remove, workaround for a bug in Uri.writeToParcel()
                .fragment("");  // TODO: Remove, workaround for a bug in Uri.writeToParcel()

        // if content path provided, insert it now
        final String contentPath = searchable.getSuggestPath();
        if (contentPath != null) {
            uriBuilder.appendEncodedPath(contentPath);
        }

        // append standard suggestion query path
        uriBuilder.appendPath(SearchManager.SUGGEST_URI_PATH_QUERY);

        // get the query selection, may be null
        String selection = searchable.getSuggestSelection();
        // inject query, either as selection args or inline
        String[] selArgs = null;
        if (selection != null) {    // use selection if provided
            selArgs = new String[] { query };
        } else {                    // no selection, use REST pattern
            uriBuilder.appendPath(query);
        }

        if (limit > 0) {
            uriBuilder.appendQueryParameter(SUGGEST_PARAMETER_LIMIT, String.valueOf(limit));
        }

        Uri uri = uriBuilder.build();

        // finally, make the query
        return mContext.getContentResolver().query(uri, null, selection, selArgs, null);
    }

    /**
     * Returns a list of the searchable activities that can be included in global search.
     *
     * @return a list containing searchable information for all searchable activities
     *         that have the <code>android:includeInGlobalSearch</code> attribute set
     *         in their searchable meta-data.
     */
    public List<SearchableInfo> getSearchablesInGlobalSearch() {
        try {
            return mService.getSearchablesInGlobalSearch();
        } catch (RemoteException e) {
            Log.e(TAG, "getSearchablesInGlobalSearch() failed: " + e);
            return null;
        }
    }

    /**
     * Returns a list of the searchable activities that handle web searches.
     *
     * @return a list of all searchable activities that handle
     *         {@link android.content.Intent#ACTION_WEB_SEARCH}.
     *
     * @hide because SearchableInfo is not part of the API.
     */
    public List<SearchableInfo> getSearchablesForWebSearch() {
        try {
            return mService.getSearchablesForWebSearch();
        } catch (RemoteException e) {
            Log.e(TAG, "getSearchablesForWebSearch() failed: " + e);
            return null;
        }
    }

    /**
     * Returns the default searchable activity for web searches.
     *
     * @return searchable information for the activity handling web searches by default.
     *
     * @hide because SearchableInfo is not part of the API.
     */
    public SearchableInfo getDefaultSearchableForWebSearch() {
        try {
            return mService.getDefaultSearchableForWebSearch();
        } catch (RemoteException e) {
            Log.e(TAG, "getDefaultSearchableForWebSearch() failed: " + e);
            return null;
        }
    }

    /**
     * Sets the default searchable activity for web searches.
     *
     * @param component Name of the component to set as default activity for web searches.
     *
     * @hide
     */
    public void setDefaultWebSearch(ComponentName component) {
        try {
            mService.setDefaultWebSearch(component);
        } catch (RemoteException e) {
            Log.e(TAG, "setDefaultWebSearch() failed: " + e);
        }
    }

    private static void debug(String msg) {
        Thread thread = Thread.currentThread();
        Log.d(TAG, msg + " (" + thread.getName() + "-" + thread.getId() + ")");
    }
}