Android:如何使用AlarmManager

“一些示例代码”不是那么简单 AlarmManager .

下面是一个显示 全局定时器 :

AlarmManager mgr=(AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
Intent i=new Intent(context, OnAlarmReceiver.class);
PendingIntent pi=PendingIntent.getBroadcast(context, 0, i, 0);

mgr.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime(), PERIOD, pi);

在这个例子中,我使用 setRepeating() . 如果你想要一声警报,你只需要使用 set() . 确保在初始参数中使用的时间基础上为报警提供时间。 集() . 在上面的示例中,我使用 AlarmManager.ELAPSED_REALTIME_WAKEUP ,所以我的时间基数是 SystemClock.elapsedRealtime() .

Here is a larger sample project 展示这种技巧。

Android示例代码中有一些很好的例子

.\android sdk\samples\android-10\apidemos\src\com\example\android\apis\app

要签出的是:

• 报警控制器.java
• 一个Shotalarm.java

首先,你需要一个接收器,当它被触发时,它可以监听你的警报。将以下内容添加到androidmanifest.xml文件中

<receiver android:name=".MyAlarmReceiver" />

然后,创建以下类

public class MyAlarmReceiver extends BroadcastReceiver { 
     @Override
     public void onReceive(Context context, Intent intent) {
         Toast.makeText(context, "Alarm went off", Toast.LENGTH_SHORT).show();
     }
}

然后,要触发警报,请使用以下方法(例如在主活动中):

AlarmManager alarmMgr = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(this, MyAlarmReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, 0);
Calendar time = Calendar.getInstance();
time.setTimeInMillis(System.currentTimeMillis());
time.add(Calendar.SECOND, 30);
alarmMgr.set(AlarmManager.RTC_WAKEUP, time.getTimeInMillis(), pendingIntent);

.

或者,更好的是,创建一个处理所有事务的类,并像这样使用它

Bundle bundle = new Bundle();
// add extras here..
MyAlarm alarm = new MyAlarm(this, bundle, 30);

这样,您就可以在一个地方完成所有操作(不要忘记编辑 AndroidManifest.xml )

public class MyAlarm extends BroadcastReceiver {
    private final String REMINDER_BUNDLE = "MyReminderBundle"; 

    // this constructor is called by the alarm manager.
    public MyAlarm(){ }

    // you can use this constructor to create the alarm. 
    //  Just pass in the main activity as the context, 
    //  any extras you'd like to get later when triggered 
    //  and the timeout
     public MyAlarm(Context context, Bundle extras, int timeoutInSeconds){
         AlarmManager alarmMgr = 
             (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
         Intent intent = new Intent(context, MyAlarm.class);
         intent.putExtra(REMINDER_BUNDLE, extras);
         PendingIntent pendingIntent =
             PendingIntent.getBroadcast(context, 0, intent, 
             PendingIntent.FLAG_UPDATE_CURRENT);
         Calendar time = Calendar.getInstance();
         time.setTimeInMillis(System.currentTimeMillis());
         time.add(Calendar.SECOND, timeoutInSeconds);
         alarmMgr.set(AlarmManager.RTC_WAKEUP, time.getTimeInMillis(),
                      pendingIntent);
     }

      @Override
     public void onReceive(Context context, Intent intent) {
         // here you can get the extras you passed in when creating the alarm
         //intent.getBundleExtra(REMINDER_BUNDLE));

         Toast.makeText(context, "Alarm went off", Toast.LENGTH_SHORT).show();
     }
}

您需要做的是首先创建您需要计划的意图。然后获得这个意图的悬而未决的内容。您可以安排活动、服务和广播。 要安排活动,例如MyActivity:

  Intent i = new Intent(getApplicationContext(), MyActivity.class);
  PendingIntent pi = PendingIntent.getActivity(getApplicationContext(),3333,i,
  PendingIntent.FLAG_CANCEL_CURRENT);

向AlarmManager提供此暂挂内容:

  //getting current time and add 5 seconds in it
  Calendar cal = Calendar.getInstance();
  cal.add(Calendar.SECOND, 5);
  //registering our pending intent with alarmmanager
  AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
  am.set(AlarmManager.RTC_WAKEUP,cal.getTimeInMillis(), pi);

现在我的活动将是 在应用程序启动5秒后启动,无论您停止应用程序或设备处于休眠状态 (由于RTC U唤醒选项)。 您可以阅读完整的示例代码 Scheduling activities, services and broadcasts #Android

我想发表评论,但代表50人,下面是。友好提示:如果您在5.1或更高版本上运行,并且使用的间隔小于一分钟,则会发生以下情况:

Suspiciously short interval 5000 millis; expanding to 60 seconds

见 here .

当您想从AlarmManager调用服务时,需要一些示例代码:

PendingIntent pi;
AlarmManager mgr;
mgr = (AlarmManager)ctx.getSystemService(Context.ALARM_SERVICE);
Intent i = new Intent(DataCollectionActivity.this, HUJIDataCollectionService.class);    
pi = PendingIntent.getService(DataCollectionActivity.this, 0, i, 0);
mgr.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime() , 1000, pi);

您不必询问用户权限。