android - 在 Android 中解锁设备屏幕时启动服务

Question

我想在屏幕解锁时运行我的服务，并在屏幕锁定时停止它。我调查了these answers并实现了它们。 但是，当我锁定屏幕时，服务会按要求停止，但当我解锁屏幕时，它不会再次启动。

运行该服务的代码如下:

public class PhonePositionService extends Service {
@Override
    public void onCreate() {
    //ADDED CODE
    IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
    filter.addAction(Intent.ACTION_SCREEN_OFF);
    BroadcastReceiver mReceiver = new BootCompletedIntentReceiver();
    registerReceiver(mReceiver, filter);
    {...}
    }
@Override
    public int onStartCommand(Intent intent, int flags, int startId) {
    int icon = R.drawable.ic_stat_bright;
    startForeground(NOTIFICATION_ID, getCompatNotification(icon));
    if (backgroundThread != null) {
      backgroundThread.start();
    }
    return START_STICKY;
  }
}

在其他文件中，我的广播接收器代码如下:

public class BootCompletedIntentReceiver extends BroadcastReceiver {
 @Override
 public void onReceive(Context context, Intent intent) {
   String action = intent.getAction();
   if(Intent.ACTION_SCREEN_ON.equals(action)) {
     // start the service
     Intent pushIntent = new Intent(context, PhonePositionService.class);
     context.startService(pushIntent);
   } else if(Intent.ACTION_SCREEN_OFF.equals(action)) {
     // stop the service
     Intent pushIntent = new Intent(context, PhonePositionService.class);
     context.stopService(pushIntent);
   }
  if ("android.intent.action.BOOT_COMPLETED".equals(intent.getAction())) {
    Intent pushIntent = new Intent(context, PhonePositionService.class);
    context.startService(pushIntent);
  }
 }
}

那为什么当我解锁手机时服务没有重新启动？

Answer 1

首先，在您拥有管理员权限之前，无法检测用户是否已解锁手机。您面临的问题是因为您在屏幕关闭时使用 stopService() 停止了 PhonePositionService:

public class BootCompletedIntentReceiver extends BroadcastReceiver {
 @Override
 public void onReceive(Context context, Intent intent) {
   String action = intent.getAction();
   if(Intent.ACTION_SCREEN_ON.equals(action)) {
     // start the service
     Intent pushIntent = new Intent(context, PhonePositionService.class);
     context.startService(pushIntent);
   } else if(Intent.ACTION_SCREEN_OFF.equals(action)) {
     // stop the service
     Intent pushIntent = new Intent(context, PhonePositionService.class);
     //This will stop the service
     context.stopService(pushIntent);
   }
  if ("android.intent.action.BOOT_COMPLETED".equals(intent.getAction())) {
    Intent pushIntent = new Intent(context, PhonePositionService.class);
    context.startService(pushIntent);
  }
 }
}

这会导致一些内存泄漏，因为 BroadcastReceiver 没有取消注册。

不鼓励让服务永远在前台运行，因为这可能导致(快速)电池耗尽。

我建议您寻找其他替代方案。但是，如果您的核心功能受到影响但您仍想继续，则可以执行以下变通办法:

将 BootCompletedIntentReceiver 作为 PhonePositionService 的内部类。您无需启动和停止服务，而是直接执行您的操作。

public class PhonePositionService extends Service {
   @Override
   public void onCreate() {
       //ADDED CODE
       IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
       filter.addAction(Intent.ACTION_SCREEN_OFF);
       BroadcastReceiver mReceiver = new BootCompletedIntentReceiver();
       registerReceiver(mReceiver, filter);
       ...
    }
    ...
    private class BootCompletedIntentReceiver extends BroadcastReceiver {
       @Override
       public void onReceive(Context context, Intent intent) {
         String action = intent.getAction();
         if(Intent.ACTION_SCREEN_ON.equals(action)) {
          //DO action for SCREEN_ON
         } else if(Intent.ACTION_SCREEN_OFF.equals(action)) {
          //Do action for SCREEN_OFF
         }

       }
   }
}