AlarmManager在错误的时间触发警报

2 回答

• 14

  对于低于19的api级别，您应该使用 AlarmManager.setRepeating() ，并且您的警报将在指定时间准确触发 . 在api级别19及以上，这将不再有效 . android中有变化，所有重复警报都是不准确的 . 因此，如果您想要实现精确的重复警报，您应该使用 AlarmManager.setExact() 安排警报，然后在下周警报触发时再次执行警报，依此类推 .

  回复于 2024-04-30T16:58:00+08:00
• 25

  因为setInexactRepeating . 使用setRepeating，它将在合适的时间处理 .

  代替：

  setInexactRepeating
  

  使用

  setRepeating
  

  setInexactRepeating，操作系统和电池友好，它将所有要完成的工作批处理接收并逐个工作，同时setRepeating立即触发警报

  另请注意：重新启动电话后，警报会被擦除，您可能必须实施启动广播接收器才能使其持久化 . 确保你没有那个运行时，你需要在Manifest中实现它，当你的应用程序不在后台你不会收到任何广播 .

  一个小例子：

  This is working code. It wakes CPU every 10 minutes until the phone turns off.

  添加到Manifest.xml：

  ...
  <uses-permission android:name="android.permission.WAKE_LOCK"></uses-permission>
  ...
  <receiver  android:process=":remote" android:name="Alarm"></receiver>
  ...
  

  码：

  package YourPackage;
      import android.app.AlarmManager;
      import android.app.PendingIntent;
      import android.content.BroadcastReceiver;
      import android.content.Context;
      import android.content.Intent;
      import android.os.PowerManager;
      import android.widget.Toast;
  
      public class Alarm extends BroadcastReceiver 
      {    
           @Override
           public void onReceive(Context context, Intent intent) 
           {   
               PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
               PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "");
               wl.acquire();
  
               // Put here YOUR code.
               Toast.makeText(context, "Alarm !!!!!!!!!!", Toast.LENGTH_LONG).show(); // For example
  
               wl.release();
           }
  
       public void SetAlarm(Context context)
       {
           AlarmManager am=(AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
           Intent i = new Intent(context, Alarm.class);
           PendingIntent pi = PendingIntent.getBroadcast(context, 0, i, 0);
           am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), 1000 * 60 * 10, pi); // Millisec * Second * Minute
       }
  
       public void CancelAlarm(Context context)
       {
           Intent intent = new Intent(context, Alarm.class);
           PendingIntent sender = PendingIntent.getBroadcast(context, 0, intent, 0);
           AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
           alarmManager.cancel(sender);
       }
   }
  

  Set Alarm from Service:

  package YourPackage;
  import android.app.Service;
  import android.content.Context;
  import android.content.Intent;
  import android.os.IBinder;
  
  public class YourService extends Service
  {
      Alarm alarm = new Alarm();
      public void onCreate()
      {
          super.onCreate();       
      }
  
      public void onStart(Context context,Intent intent, int startId)
      {
          alarm.SetAlarm(context);
      }
  
      @Override
      public IBinder onBind(Intent intent) 
      {
          return null;
      }
  }
  

  If you want set alarm repeating at phone boot time:

  添加Manifest.xml的权限：

  <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"></uses-permission>
  ...
  <receiver android:name=".AutoStart">
      <intent-filter>
          <action android:name="android.intent.action.BOOT_COMPLETED"></action>
      </intent-filter>
  </receiver>
  ...
  

  并创建新类：

  package YourPackage;
  import android.content.BroadcastReceiver;
  import android.content.Context;
  import android.content.Intent;
  
  public class AutoStart extends BroadcastReceiver
  {   
      Alarm alarm = new Alarm();
      @Override
      public void onReceive(Context context, Intent intent)
      {   
          if (intent.getAction().equals("android.intent.action.BOOT_COMPLETED"))
          {
              alarm.SetAlarm(context);
          }
      }
  }
  

  回复于 2024-04-30T16:58:00+08:00