Question

我有一个相当简单的主屏幕小部件应用程序，它在按钮点击时显示Toast。幸运的是，它仅在启动时显示Toast（或者在我在模拟器中更新apk之后）。按钮单击具有发送ACTION_APPWIDGET_UPDATE的挂起意图，但基类的onReceive（）函数不处理它。

这是我的代码：

public class WordWidget extends AppWidgetProvider {

    @Override
    public void onReceive(Context ctxt, Intent intent) {

        Log.d("WordWidget.onReceive", "onReceive");
        Log.d("WordWidget.onReceive", intent.getAction());

        if (intent.getAction()==null) {
            ctxt.startService(new Intent(ctxt, UpdateService.class));
        } else {
            super.onReceive(ctxt, intent);
        }
    }

    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {

        // To prevent any ANR timeouts, we perform the update in a service
        Log.d("WordWidget.onUpdate", "onUpdate");

        context.startService(new Intent(context, UpdateService.class));
    }

    public static class UpdateService extends Service {
        @Override
        public void onStart(Intent intent, int startId) {
            Log.d("UpdateService.onStart", "onStart");

            // Build the widget update for today
            RemoteViews updateViews = buildUpdate(this);

            // Push update for this widget to the home screen
            ComponentName thisWidget = new ComponentName(this, WordWidget.class);
            AppWidgetManager manager = AppWidgetManager.getInstance(this);
            manager.updateAppWidget(thisWidget, updateViews);
        }

        public RemoteViews buildUpdate(Context context) {

            Log.d("UpdateService.buildUpdate", "buildUpdate");

            RemoteViews updateViews = new RemoteViews(context.getPackageName(), R.layout.widget_word);

            Intent defineIntent = new Intent(context, WordWidget.class);
            defineIntent.setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE);

            PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, defineIntent, 0);

            updateViews.setOnClickPendingIntent(R.id.widget, pendingIntent);

            showToast(context);

            return updateViews;
        }

        private void showToast(Context context){
            Log.d("UpdateService.showToast", "showToast");
            Toast.makeText(context, "It is working...", Toast.LENGTH_LONG).show();          
        }

        @Override
        public IBinder onBind(Intent intent) {
            // We don't need to bind to this service
            return null;
        }
    }
}

在开机时（或刚刚重新安装后）我的小部件显示Toast，这是LogCat：

01-17 13:03:10.855: I/ActivityManager(72): Start proc com.example.android.simplewiktionary for broadcast com.example.android.simplewiktionary/.WordWidget: pid=564 uid=10036 gids={3003}
01-17 13:03:11.045: D/WordWidget.onReceive(564): onReceive
01-17 13:03:11.045: D/WordWidget.onReceive(564): android.appwidget.action.APPWIDGET_UPDATE
01-17 13:03:11.054: D/WordWidget.onUpdate(564): onUpdate
01-17 13:03:11.075: D/UpdateService.onStart(564): onStart
01-17 13:03:11.075: D/UpdateService.buildUpdate(564): buildUpdate
01-17 13:03:11.094: D/UpdateService.showToast(564): showToast
01-17 13:03:12.655: D/dalvikvm(72): GC_EXPLICIT freed 971K, 47% free 13550K/25159K, paused 7ms+52ms

现在一旦开始，如果我点击按钮，这里是LogCat：

01-17 13:04:16.095: D/dalvikvm(126): GC_EXPLICIT freed 72K, 14% free 14016K/16135K, paused 3ms+3ms
01-17 13:04:16.277: D/WordWidget.onReceive(564): onReceive
01-17 13:04:16.277: D/WordWidget.onReceive(564): android.appwidget.action.APPWIDGET_UPDATE
01-17 13:04:21.365: D/dalvikvm(564): GC_EXPLICIT freed 71K, 5% free 6307K/6595K, paused 3ms+2ms

正如您所看到的，onReceive（）基类函数未调用onUpdate（）...

你能帮我解决这个问题吗？

感谢。

Answer 1

我终于找到了为什么我自己的onUpdate（）没有被按钮点击上的super.onReceive（）执行。

使用设置为ACTION_APPWIDGET_UPDATE的操作创建一个intent不足以通过super.onReceive（）调用触发我的覆盖onUpdate（）函数的调用。根据AppWidgetProvider类的onReceive（）函数的代码，intent必须在extras字段中包含一些数据。这就是为什么第一次调用onUpdate（）时（当它是来自系统的真实ACTION_APPWIDGET_UPDATE意图时），而不是当我点击按钮时......

以下是AppWidgetProvider.java文件中的代码：

// BEGIN_INCLUDE(onReceive)
public void  [More ...] onReceive(Context context, Intent intent) {
 // Protect against rogue update broadcasts (not really a security issue,
 // just filter bad broacasts out so subclasses are less likely to crash).
 String action = intent.getAction();
 if (AppWidgetManager.ACTION_APPWIDGET_UPDATE.equals(action)) {
     Bundle extras = intent.getExtras();
     if (extras != null) {
         int[] appWidgetIds = extras.getIntArray(AppWidgetManager.EXTRA_APPWIDGET_IDS);
         if (appWidgetIds != null && appWidgetIds.length > 0) {
             this.onUpdate(context, AppWidgetManager.getInstance(context), appWidgetIds);
         }
     }
 }
 else if (AppWidgetManager.ACTION_APPWIDGET_DELETED.equals(action)) {
     Bundle extras = intent.getExtras();
     if (extras != null && extras.containsKey(AppWidgetManager.EXTRA_APPWIDGET_ID)) {
         final int appWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID);
         this.onDeleted(context, new int[] { appWidgetId });
     }
 }
 else if (AppWidgetManager.ACTION_APPWIDGET_ENABLED.equals(action)) {
     this.onEnabled(context);
 }
 else if (AppWidgetManager.ACTION_APPWIDGET_DISABLED.equals(action)) {
     this.onDisabled(context);
 }
}

感谢。

Answer 2

我建议您不要试图强制调用onUpdate，而是设置PendingIntent以启动服务：

Intent intent = new Intent(context, UpdateService.class);    
PendingIntent pi = PendingIntent.getService(context, 0, intent, 0);

如果这不起作用或者对您来说不是一个可行的解决方案，请告诉我。

为什么基类onReceive（）函数不调用onUpdate（）？

2 个答案: