android/appwidget/AppWidgetHost.java

/*
 * Copyright (C) 2009 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.appwidget;

import java.util.ArrayList;
import java.util.HashMap;

import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.Context;
import android.content.Intent;
import android.content.IntentSender;
import android.os.Binder;
import android.os.Handler;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.os.Process;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.widget.RemoteViews;
import android.widget.RemoteViews.OnClickHandler;

import com.android.internal.appwidget.IAppWidgetHost;
import com.android.internal.appwidget.IAppWidgetService;

/**
 * AppWidgetHost provides the interaction with the AppWidget service for apps,
 * like the home screen, that want to embed AppWidgets in their UI.
 */
public class AppWidgetHost {

    static final int HANDLE_UPDATE = 1;
    static final int HANDLE_PROVIDER_CHANGED = 2;
    static final int HANDLE_PROVIDERS_CHANGED = 3;
    static final int HANDLE_VIEW_DATA_CHANGED = 4;

    final static Object sServiceLock = new Object();
    static IAppWidgetService sService;
    private DisplayMetrics mDisplayMetrics;

    Context mContext;
    Handler mHandler;
    int mHostId;
    Callbacks mCallbacks = new Callbacks();
    final HashMap<Integer,AppWidgetHostView> mViews = new HashMap<Integer, AppWidgetHostView>();
    private OnClickHandler mOnClickHandler;

    class Callbacks extends IAppWidgetHost.Stub {
        public void updateAppWidget(int appWidgetId, RemoteViews views) {
            if (isLocalBinder() && views != null) {
                views = views.clone();
            }
            Message msg = mHandler.obtainMessage(HANDLE_UPDATE, appWidgetId, 0, views);
            msg.sendToTarget();
        }

        public void providerChanged(int appWidgetId, AppWidgetProviderInfo info) {
            if (isLocalBinder() && info != null) {
                info = info.clone();
            }
            Message msg = mHandler.obtainMessage(HANDLE_PROVIDER_CHANGED,
                    appWidgetId, 0, info);
            msg.sendToTarget();
        }

        public void providersChanged() {
            mHandler.obtainMessage(HANDLE_PROVIDERS_CHANGED).sendToTarget();
        }

        public void viewDataChanged(int appWidgetId, int viewId) {
            Message msg = mHandler.obtainMessage(HANDLE_VIEW_DATA_CHANGED,
                    appWidgetId, viewId);
            msg.sendToTarget();
        }
    }

    class UpdateHandler extends Handler {
        public UpdateHandler(Looper looper) {
            super(looper);
        }

        public void handleMessage(Message msg) {
            switch (msg.what) {
                case HANDLE_UPDATE: {
                    updateAppWidgetView(msg.arg1, (RemoteViews)msg.obj);
                    break;
                }
                case HANDLE_PROVIDER_CHANGED: {
                    onProviderChanged(msg.arg1, (AppWidgetProviderInfo)msg.obj);
                    break;
                }
                case HANDLE_PROVIDERS_CHANGED: {
                    onProvidersChanged();
                    break;
                }
                case HANDLE_VIEW_DATA_CHANGED: {
                    viewDataChanged(msg.arg1, msg.arg2);
                    break;
                }
            }
        }
    }

    public AppWidgetHost(Context context, int hostId) {
        this(context, hostId, null, context.getMainLooper());
    }

    /**
     * @hide
     */
    public AppWidgetHost(Context context, int hostId, OnClickHandler handler, Looper looper) {
        mContext = context;
        mHostId = hostId;
        mOnClickHandler = handler;
        mHandler = new UpdateHandler(looper);
        mDisplayMetrics = context.getResources().getDisplayMetrics();
        bindService();
    }


    private static void bindService() {
        synchronized (sServiceLock) {
            if (sService == null) {
                IBinder b = ServiceManager.getService(Context.APPWIDGET_SERVICE);
                sService = IAppWidgetService.Stub.asInterface(b);
            }
        }
    }

    /**
     * Start receiving onAppWidgetChanged calls for your AppWidgets.  Call this when your activity
     * becomes visible, i.e. from onStart() in your Activity.
     */
    public void startListening() {
        int[] updatedIds;
        ArrayList<RemoteViews> updatedViews = new ArrayList<RemoteViews>();
        try {
            updatedIds = sService.startListening(mCallbacks, mContext.getPackageName(), mHostId,
                    updatedViews);
        }
        catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }

        final int N = updatedIds.length;
        for (int i = 0; i < N; i++) {
            updateAppWidgetView(updatedIds[i], updatedViews.get(i));
        }
    }

    /**
     * Stop receiving onAppWidgetChanged calls for your AppWidgets.  Call this when your activity is
     * no longer visible, i.e. from onStop() in your Activity.
     */
    public void stopListening() {
        try {
            sService.stopListening(mContext.getPackageName(), mHostId);
        }
        catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }

        // This is here because keyguard needs it since it'll be switching users after this call.
        // If it turns out other apps need to call this often, we should re-think how this works.
        clearViews();
    }

    /**
     * Get a appWidgetId for a host in the calling process.
     *
     * @return a appWidgetId
     */
    public int allocateAppWidgetId() {
        try {
            return sService.allocateAppWidgetId(mContext.getPackageName(), mHostId);
        }
        catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
    }

    /**
     * Starts an app widget provider configure activity for result on behalf of the caller.
     * Use this method if the provider is in another profile as you are not allowed to start
     * an activity in another profile. The provided intent must have action {@link
     * AppWidgetManager#ACTION_APPWIDGET_CONFIGURE}. The widget id must be specified by
     * the {@link AppWidgetManager#EXTRA_APPWIDGET_ID} extra. The provider configure
     * activity must be specified as the component name of the intent via {@link
     * Intent#setComponent(android.content.ComponentName)}. The user profile under which
     * the provider operates is specified via the {@link
     * AppWidgetManager#EXTRA_APPWIDGET_PROVIDER_PROFILE} extra. If a user profile is
     * not provided, the current user is used. Finally, you can optionally provide a
     * request code that is returned in {@link Activity#onActivityResult(int, int,
     * android.content.Intent)}.
     *
     * @param activity The activity from which to start the configure one.
     * @param intent Properly populated intent for launching the configuration activity.
     * @param requestCode Optional request code retuned with the result.
     *
     * @throws android.content.ActivityNotFoundException If the activity is not found.
     *
     * @see AppWidgetProviderInfo#getProfile()
     */
    public final void startAppWidgetConfigureActivityForResult(Activity activity, Intent intent,
            int requestCode) {
        try {
            IntentSender intentSender = sService.createAppWidgetConfigIntentSender(
                    mContext.getPackageName(), intent);
            if (intentSender != null) {
                activity.startIntentSenderForResult(intentSender, requestCode, null, 0, 0, 0);
            } else {
                throw new ActivityNotFoundException();
            }
        } catch (IntentSender.SendIntentException e) {
            throw new ActivityNotFoundException();
        } catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
    }

    /**
     * Gets a list of all the appWidgetIds that are bound to the current host
     *
     * @hide
     */
    public int[] getAppWidgetIds() {
        try {
            if (sService == null) {
                bindService();
            }
            return sService.getAppWidgetIdsForHost(mContext.getPackageName(), mHostId);
        } catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
    }

    private boolean isLocalBinder() {
        return Process.myPid() == Binder.getCallingPid();
    }

    /**
     * Stop listening to changes for this AppWidget.
     */
    public void deleteAppWidgetId(int appWidgetId) {
        synchronized (mViews) {
            mViews.remove(appWidgetId);
            try {
                sService.deleteAppWidgetId(mContext.getPackageName(), appWidgetId);
            }
            catch (RemoteException e) {
                throw new RuntimeException("system server dead?", e);
            }
        }
    }

    /**
     * Remove all records about this host from the AppWidget manager.
     * <ul>
     *   <li>Call this when initializing your database, as it might be because of a data wipe.</li>
     *   <li>Call this to have the AppWidget manager release all resources associated with your
     *   host.  Any future calls about this host will cause the records to be re-allocated.</li>
     * </ul>
     */
    public void deleteHost() {
        try {
            sService.deleteHost(mContext.getPackageName(), mHostId);
        }
        catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
    }

    /**
     * Remove all records about all hosts for your package.
     * <ul>
     *   <li>Call this when initializing your database, as it might be because of a data wipe.</li>
     *   <li>Call this to have the AppWidget manager release all resources associated with your
     *   host.  Any future calls about this host will cause the records to be re-allocated.</li>
     * </ul>
     */
    public static void deleteAllHosts() {
        try {
            sService.deleteAllHosts();
        }
        catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
    }

    /**
     * Create the AppWidgetHostView for the given widget.
     * The AppWidgetHost retains a pointer to the newly-created View.
     */
    public final AppWidgetHostView createView(Context context, int appWidgetId,
            AppWidgetProviderInfo appWidget) {
        AppWidgetHostView view = onCreateView(mContext, appWidgetId, appWidget);
        view.setOnClickHandler(mOnClickHandler);
        view.setAppWidget(appWidgetId, appWidget);
        synchronized (mViews) {
            mViews.put(appWidgetId, view);
        }
        RemoteViews views;
        try {
            views = sService.getAppWidgetViews(mContext.getPackageName(), appWidgetId);
        } catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
        view.updateAppWidget(views);

        return view;
    }

    /**
     * Called to create the AppWidgetHostView.  Override to return a custom subclass if you
     * need it.  {@more}
     */
    protected AppWidgetHostView onCreateView(Context context, int appWidgetId,
            AppWidgetProviderInfo appWidget) {
        return new AppWidgetHostView(context, mOnClickHandler);
    }

    /**
     * Called when the AppWidget provider for a AppWidget has been upgraded to a new apk.
     */
    protected void onProviderChanged(int appWidgetId, AppWidgetProviderInfo appWidget) {
        AppWidgetHostView v;

        // Convert complex to dp -- we are getting the AppWidgetProviderInfo from the
        // AppWidgetService, which doesn't have our context, hence we need to do the
        // conversion here.
        appWidget.minWidth =
            TypedValue.complexToDimensionPixelSize(appWidget.minWidth, mDisplayMetrics);
        appWidget.minHeight =
            TypedValue.complexToDimensionPixelSize(appWidget.minHeight, mDisplayMetrics);
        appWidget.minResizeWidth =
            TypedValue.complexToDimensionPixelSize(appWidget.minResizeWidth, mDisplayMetrics);
        appWidget.minResizeHeight =
            TypedValue.complexToDimensionPixelSize(appWidget.minResizeHeight, mDisplayMetrics);

        synchronized (mViews) {
            v = mViews.get(appWidgetId);
        }
        if (v != null) {
            v.resetAppWidget(appWidget);
        }
    }

    /**
     * Called when the set of available widgets changes (ie. widget containing packages
     * are added, updated or removed, or widget components are enabled or disabled.)
     */
    protected void onProvidersChanged() {
        // Does nothing
    }

    void updateAppWidgetView(int appWidgetId, RemoteViews views) {
        AppWidgetHostView v;
        synchronized (mViews) {
            v = mViews.get(appWidgetId);
        }
        if (v != null) {
            v.updateAppWidget(views);
        }
    }

    void viewDataChanged(int appWidgetId, int viewId) {
        AppWidgetHostView v;
        synchronized (mViews) {
            v = mViews.get(appWidgetId);
        }
        if (v != null) {
            v.viewDataChanged(viewId);
        }
    }

    /**
     * Clear the list of Views that have been created by this AppWidgetHost.
     */
    protected void clearViews() {
        mViews.clear();
    }
}