Java tutorial
/* * 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 android.annotation.NonNull; import android.annotation.Nullable; import android.annotation.UnsupportedAppUsage; import android.app.Activity; import android.content.ActivityNotFoundException; import android.content.Context; import android.content.IntentSender; import android.content.pm.PackageManager; import android.os.Binder; import android.os.Bundle; 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.SparseArray; import android.widget.RemoteViews; import android.widget.RemoteViews.OnClickHandler; import com.android.internal.R; import com.android.internal.appwidget.IAppWidgetHost; import com.android.internal.appwidget.IAppWidgetService; import java.lang.ref.WeakReference; import java.util.List; /** * 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; @UnsupportedAppUsage static final int HANDLE_VIEW_DATA_CHANGED = 4; final static Object sServiceLock = new Object(); @UnsupportedAppUsage static IAppWidgetService sService; static boolean sServiceInitialized = false; private DisplayMetrics mDisplayMetrics; private String mContextOpPackageName; @UnsupportedAppUsage private final Handler mHandler; private final int mHostId; private final Callbacks mCallbacks; private final SparseArray<AppWidgetHostView> mViews = new SparseArray<>(); private OnClickHandler mOnClickHandler; static class Callbacks extends IAppWidgetHost.Stub { private final WeakReference<Handler> mWeakHandler; public Callbacks(Handler handler) { mWeakHandler = new WeakReference<>(handler); } public void updateAppWidget(int appWidgetId, RemoteViews views) { if (isLocalBinder() && views != null) { views = views.clone(); } Handler handler = mWeakHandler.get(); if (handler == null) { return; } Message msg = handler.obtainMessage(HANDLE_UPDATE, appWidgetId, 0, views); msg.sendToTarget(); } public void providerChanged(int appWidgetId, AppWidgetProviderInfo info) { if (isLocalBinder() && info != null) { info = info.clone(); } Handler handler = mWeakHandler.get(); if (handler == null) { return; } Message msg = handler.obtainMessage(HANDLE_PROVIDER_CHANGED, appWidgetId, 0, info); msg.sendToTarget(); } public void providersChanged() { Handler handler = mWeakHandler.get(); if (handler == null) { return; } handler.obtainMessage(HANDLE_PROVIDERS_CHANGED).sendToTarget(); } public void viewDataChanged(int appWidgetId, int viewId) { Handler handler = mWeakHandler.get(); if (handler == null) { return; } Message msg = handler.obtainMessage(HANDLE_VIEW_DATA_CHANGED, appWidgetId, viewId); msg.sendToTarget(); } private static boolean isLocalBinder() { return Process.myPid() == Binder.getCallingPid(); } } 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 */ @UnsupportedAppUsage public AppWidgetHost(Context context, int hostId, OnClickHandler handler, Looper looper) { mContextOpPackageName = context.getOpPackageName(); mHostId = hostId; mOnClickHandler = handler; mHandler = new UpdateHandler(looper); mCallbacks = new Callbacks(mHandler); mDisplayMetrics = context.getResources().getDisplayMetrics(); bindService(context); } private static void bindService(Context context) { synchronized (sServiceLock) { if (sServiceInitialized) { return; } sServiceInitialized = true; PackageManager packageManager = context.getPackageManager(); if (!packageManager.hasSystemFeature(PackageManager.FEATURE_APP_WIDGETS) && !context.getResources().getBoolean(R.bool.config_enableAppWidgetService)) { return; } 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() { if (sService == null) { return; } final int[] idsToUpdate; synchronized (mViews) { int N = mViews.size(); idsToUpdate = new int[N]; for (int i = 0; i < N; i++) { idsToUpdate[i] = mViews.keyAt(i); } } List<PendingHostUpdate> updates; try { updates = sService.startListening(mCallbacks, mContextOpPackageName, mHostId, idsToUpdate).getList(); } catch (RemoteException e) { throw new RuntimeException("system server dead?", e); } int N = updates.size(); for (int i = 0; i < N; i++) { PendingHostUpdate update = updates.get(i); switch (update.type) { case PendingHostUpdate.TYPE_VIEWS_UPDATE: updateAppWidgetView(update.appWidgetId, update.views); break; case PendingHostUpdate.TYPE_PROVIDER_CHANGED: onProviderChanged(update.appWidgetId, update.widgetInfo); break; case PendingHostUpdate.TYPE_VIEW_DATA_CHANGED: viewDataChanged(update.appWidgetId, update.viewId); } } } /** * 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() { if (sService == null) { return; } try { sService.stopListening(mContextOpPackageName, mHostId); } catch (RemoteException e) { throw new RuntimeException("system server dead?", e); } } /** * Get a appWidgetId for a host in the calling process. * * @return a appWidgetId */ public int allocateAppWidgetId() { if (sService == null) { return -1; } try { return sService.allocateAppWidgetId(mContextOpPackageName, 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. You can optionally provide a request code that is * returned in {@link Activity#onActivityResult(int, int, android.content.Intent)} and * an options bundle to be passed to the started activity. * <p> * Note that the provided app widget has to be bound for this method to work. * </p> * * @param activity The activity from which to start the configure one. * @param appWidgetId The bound app widget whose provider's config activity to start. * @param requestCode Optional request code retuned with the result. * @param intentFlags Optional intent flags. * * @throws android.content.ActivityNotFoundException If the activity is not found. * * @see AppWidgetProviderInfo#getProfile() */ public final void startAppWidgetConfigureActivityForResult(@NonNull Activity activity, int appWidgetId, int intentFlags, int requestCode, @Nullable Bundle options) { if (sService == null) { return; } try { IntentSender intentSender = sService.createAppWidgetConfigIntentSender(mContextOpPackageName, appWidgetId, intentFlags); if (intentSender != null) { activity.startIntentSenderForResult(intentSender, requestCode, null, 0, 0, 0, options); } 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 */ public int[] getAppWidgetIds() { if (sService == null) { return new int[0]; } try { return sService.getAppWidgetIdsForHost(mContextOpPackageName, mHostId); } catch (RemoteException e) { throw new RuntimeException("system server dead?", e); } } /** * Stop listening to changes for this AppWidget. */ public void deleteAppWidgetId(int appWidgetId) { if (sService == null) { return; } synchronized (mViews) { mViews.remove(appWidgetId); try { sService.deleteAppWidgetId(mContextOpPackageName, 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() { if (sService == null) { return; } try { sService.deleteHost(mContextOpPackageName, 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() { if (sService == null) { return; } 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) { if (sService == null) { return null; } AppWidgetHostView view = onCreateView(context, appWidgetId, appWidget); view.setOnClickHandler(mOnClickHandler); view.setAppWidget(appWidgetId, appWidget); synchronized (mViews) { mViews.put(appWidgetId, view); } RemoteViews views; try { views = sService.getAppWidgetViews(mContextOpPackageName, 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.updateDimensions(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() { synchronized (mViews) { mViews.clear(); } } }