android - 修改根据屏幕状态触发业务的告警

Question

我目前正在使用广播接收器启动服务，该接收器会在设备启动后 60 秒触发。此广播接收器触发警报，以便我的服务每 60 秒运行一次。代码如下:

public class ScheduleReceiver extends BroadcastReceiver {
    // Restart service every 60 seconds
    private static final long REPEAT_TIME = 1000 * 60;

    @Override
    public void onReceive(Context context, Intent intent) {
        AlarmManager service = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        Intent i = new Intent(context, StartServiceReceiver.class);
        PendingIntent pending = PendingIntent.getBroadcast(context, 0, i,PendingIntent.FLAG_CANCEL_CURRENT);

        Calendar cal = Calendar.getInstance();
        // Start 60 seconds after boot completed
        cal.add(Calendar.SECOND, 60);
        // Fetch every 60 seconds
        // InexactRepeating allows Android to optimize the energy consumption
        service.setInexactRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), REPEAT_TIME, pending);
    }
}

上面启动服务如下:

public class StartServiceReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Intent service = new Intent(context, PhotoService.class);
        context.startService(service);
    }
} 

我想以某种方式修改它，以便我的服务在手机屏幕打开时每 60 秒运行一次，在关闭时每 20 分钟运行一次。

最好的方法是什么？我可以在屏幕关闭/打开时动态修改警报吗？

感谢您的帮助，

问候，

小狗

Answer 1

好吧，我已经找到了如何做到这一点，所以我想我会把它放在这里以防其他人好奇。 (总是欢迎更优雅的解决方案):

首先，在我的服务中，我将以下内容添加到 OnCreate:

 @Override
 public void onCreate() {
     super.onCreate();
     // REGISTER RECEIVER THAT HANDLES SCREEN ON AND SCREEN OFF LOGIC
     IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
     filter.addAction(Intent.ACTION_SCREEN_OFF);
     BroadcastReceiver mReceiver = new ScheduleReceiver();
     registerReceiver(mReceiver, filter);
 }

这样做是为了让我的广播接收器可以处理这些事件。显然你不能通过 xml 中的 intent-filters 注册这些。

这意味着当创建服务时，它确保可以处理这些额外的系统操作。

然后我将我的广播接收器修改为:

public class ScheduleReceiver extends BroadcastReceiver {
    private static final int ALARM_ID = 909;

    @Override
    public void onReceive(Context context, Intent intent) {
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);   
        AlarmManager service = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        Intent i = new Intent(context, StartServiceReceiver.class);
        PendingIntent pending = PendingIntent.getBroadcast(context, ALARM_ID, i,PendingIntent.FLAG_CANCEL_CURRENT);
        service.cancel(pending);

        Calendar cal = Calendar.getInstance();
        cal.add(Calendar.SECOND, 60); //Delay startup by one minute - This is useful to prevent over utilization of resources at boot

        // Start alarm. Set a long repeat time if the screen is off and a short repeat time if the screen is on
        if (intent.getAction().equals(Intent.ACTION_SCREEN_ON) || intent.getAction().equals(Intent.ACTION_BOOT_COMPLETED)){
            service.setInexactRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), 60000, pending);
        }
        else if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)){
            service.setInexactRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), 600000, pending);
        }
    }
}

从上面我取消了所有具有相同未决 Intent 的当前警报，然后每当屏幕关闭/打开时我设置一个新警报。

这似乎对我有用。一如既往地欢迎任何改进。