EmailWidgetLoader.java revision 44f5cd67c97da6a5c7e63a73b4dca7057b83cdbb 
1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.email.widget;
18
19import com.android.email.data.ThrottlingCursorLoader;
20import com.android.emailcommon.provider.EmailContent;
21import com.android.emailcommon.provider.EmailContent.Message;
22import com.android.emailcommon.provider.EmailContent.MessageColumns;
23import com.android.emailcommon.provider.Mailbox;
24
25import android.content.Context;
26import android.database.Cursor;
27import android.database.CursorWrapper;
28
29/**
30 * Loader for {@link EmailWidget}.
31 *
32 * This loader not only loads the messages, but also:
33 * - The number of accounts.
34 * - The message count shown in the widget header.
35 *   It's currently just the same as the message count, but this will be updated to the unread
36 *   counts for inboxes.
37 */
38class EmailWidgetLoader extends ThrottlingCursorLoader {
39    private static final String SORT_TIMESTAMP_DESCENDING = MessageColumns.TIMESTAMP + " DESC";
40
41    // The projection to be used by the WidgetLoader
42    private static final String[] WIDGET_PROJECTION = new String[] {
43            EmailContent.RECORD_ID, MessageColumns.DISPLAY_NAME, MessageColumns.TIMESTAMP,
44            MessageColumns.SUBJECT, MessageColumns.FLAG_READ, MessageColumns.FLAG_FAVORITE,
45            MessageColumns.FLAG_ATTACHMENT, MessageColumns.MAILBOX_KEY, MessageColumns.SNIPPET,
46            MessageColumns.ACCOUNT_KEY, MessageColumns.FLAGS
47            };
48    public static final int WIDGET_COLUMN_ID = 0;
49    public static final int WIDGET_COLUMN_DISPLAY_NAME = 1;
50    public static final int WIDGET_COLUMN_TIMESTAMP = 2;
51    public static final int WIDGET_COLUMN_SUBJECT = 3;
52    public static final int WIDGET_COLUMN_FLAG_READ = 4;
53    public static final int WIDGET_COLUMN_FLAG_FAVORITE = 5;
54    public static final int WIDGET_COLUMN_FLAG_ATTACHMENT = 6;
55    public static final int WIDGET_COLUMN_MAILBOX_KEY = 7;
56    public static final int WIDGET_COLUMN_SNIPPET = 8;
57    public static final int WIDGET_COLUMN_ACCOUNT_KEY = 9;
58    public static final int WIDGET_COLUMN_FLAGS = 10;
59
60    private long mAccountId;
61    private long mMailboxId;
62
63    /**
64     * The actual data returned by this loader.
65     */
66    static class CursorWithCounts extends CursorWrapper {
67        private final int mMessageCount;
68
69        public CursorWithCounts(Cursor cursor, int messageCount) {
70            super(cursor);
71            mMessageCount = messageCount;
72        }
73
74        /**
75         * @return The count that should be shown on the widget header.
76         *     Note depending on the view, it may be the unread count, which is different from
77         *     the record count (i.e. {@link #getCount()}}.
78         */
79        public int getMessageCount() {
80            return mMessageCount;
81        }
82    }
83
84    private final Context mContext;
85
86    EmailWidgetLoader(Context context) {
87        super(context, Message.CONTENT_URI, WIDGET_PROJECTION, null,
88                null, SORT_TIMESTAMP_DESCENDING);
89        mContext = context;
90    }
91
92    @Override
93    public Cursor loadInBackground() {
94        final Cursor messagesCursor = super.loadInBackground();
95
96        // Reset the notification Uri to our Message table notifier URI
97        messagesCursor.setNotificationUri(mContext.getContentResolver(), Message.NOTIFIER_URI);
98
99        final int messageCount;
100        if (mMailboxId != Mailbox.QUERY_ALL_FAVORITES) {
101            String selection = "(" + getSelection() + " ) AND " + MessageColumns.FLAG_READ + " = 0";
102            messageCount = EmailContent.count(mContext, Message.CONTENT_URI, selection,
103                    getSelectionArgs());
104        } else {
105            // Just use the number of all messages shown.
106            messageCount = messagesCursor.getCount();
107        }
108
109        return new CursorWithCounts(messagesCursor, messageCount);
110    }
111
112    /**
113     * Stop any pending load, reset selection parameters, and start loading.
114     *
115     * Must be called from the UI thread
116     *
117     * @param accountId
118     * @param mailboxId
119     */
120    void load(long accountId, long mailboxId) {
121        reset();
122        mAccountId = accountId;
123        mMailboxId = mailboxId;
124        setSelection(Message.PER_ACCOUNT_UNREAD_SELECTION);
125        setSelectionArgs(new String[]{ Long.toString(mAccountId) });
126        startLoading();
127    }
128}
129