android - NotificationManager 启动空 Activity

Question

我创建了一个通过 AlarmManager 启动的简单状态通知。一切正常(通知的内容、标题、点击时启动的 Activity 等)。不幸的是，当调用通知时(即，AlarmManager 关闭)，将启动并显示一个空 Activity 。该 Activity 仅在状态栏中包含我的应用程序的名称及其图标。实际 Activity 本身是空白的。同样，当通知关闭并首次出现在状态栏中时，就会发生这种情况。当我再次点击通知时，它会转到正确的待处理 Activity 。这是我的代码:

下面是设置 AlarmManager 调用 Notification 的代码:

//Use AlarmManager to trigger the notification/alarm.
AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE); 

//PendingIntent to launch activity when the alarm triggers.                    
Intent intent = new Intent("com.YouForgotWhat.FlightGear.DisplayNotification");

PendingIntent displayIntent = PendingIntent.getActivity(getBaseContext(), 0, intent, 0);   

//Set an alarm to go off at 30 minutes before fuel runs out.
alarmManager.set(AlarmManager.RTC_WAKEUP, endTimeInMillis - (30*60*1000), displayIntent);

下面是通知本身的实际代码(它在另一个 Activity 中):

公共(public)类 DisplayNotification 扩展 SherlockActivity { 私有(private)上下文上下文=这个；

public void onCreate(Bundle paramBundle) {
    super.onCreate(paramBundle);

    NotificationManager mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this);

    mBuilder.setContentTitle("Your fuel may be running low.")
            .setContentText("There are 30 mins left on your timer. Check your fuel gauges.")
            .setSmallIcon(R.drawable.ic_launcher);

    Intent intent = new Intent(this, FuelTimer.class);

    PendingIntent in = PendingIntent.getActivity(getApplicationContext(), 0, intent, 0);
    mBuilder.setContentIntent(in);

    mNotificationManager.notify(0, mBuilder.build());

}

}

我该怎么做才能解决这个问题？谢谢!

Answer 1

您正在启动一个 Activity 来发出通知，一开始您看到一个空的 Activity 是有道理的 - 这正是您刚刚启动的。请改用 BroadcastReceiver。

所以当它收到:

public class Receiver extends BroadcastReceiver{
  @Override
  public void onReceive(Context context, Intent intent)
  {
    NotificationManager mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context);

    mBuilder.setContentTitle("Your fuel may be running low.")
      .setContentText("There are 30 mins left on your timer. Check your fuel gauges.")
      .setSmallIcon(R.drawable.ic_launcher);

    Intent intent = new Intent(context, FuelTimer.class);

    PendingIntent in = PendingIntent.getActivity(context, 0, intent, 0);
    mBuilder.setContentIntent(in);

    mNotificationManager.notify(0, mBuilder.build());

   } 
}

您必须将接收器添加到 list 中:

<receiver android:name="com.YouForgotWhat.FlightGear.Receiver" >
            <intent-filter>
                <action android:name="com.YouForgotWhat.FlightGear.DisplayNotification" />
            </intent-filter>
 </receiver>

最后，更改代码以启动接收器，就像

//PendingIntent to launch activity when the alarm triggers.                    
Intent intent = new Intent("com.YouForgotWhat.FlightGear.DisplayNotification");

PendingIntent displayIntent = PendingIntent.getBroadcast(getBaseContext(), 0, intent, 0);