如何解决未显示应用时 Android 前台停止
我是 android 新手，正在开发一个 Android 应用程序，该应用程序每隔几秒进行一次测量，并将这些测量值链接到用户的当前位置。即使用户正在使用手机（应用程序最小化）或屏幕锁定时，仍应收集数据。我要注意的是，此应用仅供内部使用（而非在 Google Play 商店中），并且必须获得用户的完全许可！
在查看 Android 文档时，我发现前台服务可能是我的解决方案。所以我按照记录的方式实现了这项服务。在对应用程序进行编程时，一切似乎都运行良好，但是当我开始制作应用程序的发布版本并测试应用程序时，我注意到了一些意外行为。这是我用于我的服务并从我的活动中调用服务的代码：
public class LocationService extends Service {
private final LocationServiceBinder binder = new LocationServiceBinder();
private final String TAG = "LocationService";
private LocationListener mLocationListener;
private LocationManager mLocationManager;
private PowerManager.WakeLock wakeLock;
private Timer timer;
private final int LOCATION_INTERVAL = 500;
private final int LOCATION_DISTANCE = 1;
@Override
public void onCreate() {
startForeground(12345678,getNotification());
}
@Override
public int onStartCommand(Intent intent,int flags,int startId) {
PowerManager pm = (PowerManager)getSystemService(POWER_SERVICE);
wakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,"Service:WakeLock");
wakeLock.acquire();
startTracking();
super.onStartCommand(intent,flags,startId);
return START_STICKY;
}
@Override
public void onDestroy() {
super.onDestroy();
}
@Override
public void onTaskRemoved(Intent rootIntent) {
task.cancel();
wakeLock.release();
if (timer != null) {
timer.cancel();
timer.purge();
timer.cancel();
timer = null;
}
if (mLocationManager != null) {
try {
mLocationManager.removeUpdates(mLocationListener);
} catch (Exception ex) {
Log.i(TAG,"fail to remove location listeners,ignore",ex);
}
}
stopForeground(true);
stopSelf();
super.onTaskRemoved(rootIntent);
}
private Notification getNotification() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
NotificationChannel channel = new NotificationChannel("channel_01","My Channel",NotificationManager.IMPORTANCE_DEFAULT);
NotificationManager notificationManager = getSystemService(NotificationManager.class);
notificationManager.createNotificationChannel(channel);
}
Intent intent = new Intent(this,MainActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this,intent,0);
return new NotificationCompat.Builder(this,"channel_01")
.setContentTitle("APP")
.setContentText("App is running!")
.setContentIntent(pendingIntent).build();
}
@Override
public IBinder onBind(Intent intent) {
return binder;
}
public class LocationServiceBinder extends Binder {
public LocationService getService() {
return LocationService.this;
}
}
private TimerTask task = new TimerTask() {
@Override
public void run() {
requestLocationInformation();
}
};
public void startTracking() {
initializeLocationManager();
mLocationListener = new LocationListener(LocationManager.GPS_PROVIDER);
if (timer == null) {
timer = new Timer("Measurements");
timer.scheduleAtFixedRate(task,1000,5000);
}
try {
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,LOCATION_INTERVAL,LOCATION_DISTANCE,mLocationListener);
} catch (java.lang.SecurityException ex) {
Log.i(TAG,"fail to request location update,ex);
} catch (IllegalArgumentException ex) {
Log.d(TAG,"gps provider does not exist " + ex.getMessage());
}
}
}
private class LocationListener implements android.location.LocationListener {
private Location lastLocation = null;
private final String TAG = "LocationListener";
private Location mLastLocation;
public LocationListener(String provider) {
mLastLocation = new Location(provider);
}
}
public void requestLocationUpdates() {
try {
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,mLocationListener);
} catch (java.lang.SecurityException ex) {
Log.i(TAG,ex);
} catch (IllegalArgumentException ex) {
Log.d(TAG,"gps provider does not exist " + ex.getMessage());
}
}
private void initializeLocationManager() {
if (mLocationManager == null) {
mLocationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
}
}
private void requestLocationInformation() {
if (ActivityCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this,Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
Location location = mLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null && swbRunning) {
String locInfo = "latitude:" + location.getLatitude() + " longitude:" + location.getLongitude() + " accuracy: " + location.getAccuracy() + "\n";
Log.d(TAG,"Location --> " + locInfo);
}
}
}
}
public class MainActivity extends ReactActivity {
//permissions to be requested at runtime - needed for android 6.0+
static String[] runtimePermissions = { Manifest.permission.INTERNET,Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE,Manifest.permission.ACCESS_FINE_LOCATION,Manifest.permission.READ_PHONE_STATE,Manifest.permission.WAKE_LOCK };
static int permissionRequestCode = 1;
private LocationService locaService;
@RequiresApi(api = Build.VERSION_CODES.M)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (!havePermissions()) {
requestPermissions(runtimePermissions,permissionRequestCode);
} else {
Intent intent = new Intent(this,LocationService.class);
bindService(intent,serviceConnection,Context.BIND_AUTO_CREATE);
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
startForegroundService(intent);
else
startService(intent);
}
}
private ServiceConnection serviceConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className,IBinder service) {
locaService = ((LocationService.LocationServiceBinder) service).getService();
}
public void onServiceDisconnected(ComponentName className) {
locaService = null;
}
};
为了测试应用程序，我使用了三星 Galaxy A42 (android 11) 设备，我们的用户也使用该设备。 在发布版本中，一切正常，直到应用程序最小化或屏幕被锁定。 我调查了这个问题，并根据我可以在网上找到的关于这个问题的信息， 我尝试了一些不同的解决方案。我添加了一个部分唤醒锁以保持设备平稳运行，并且我还按照以下帖子的建议将 stopWithTask=false 添加到 android manifest。我还在没有此问题的旧设备 (android 8) 上运行该应用程序。
Keep background service running after killing an application My Android 11 app stops running when the user puts it into the background unless the phone is connected to power Android keep screen on on Samsung devices
正如上一篇文章中提到的，三星以执行电池优化而闻名，这可能会影响运行前台服务的应用程序。所以我使用了 https://dontkillmyapp.com/ 上的建议，但这并不能解决问题。 由于我尝试了我能找到的所有解决方案，我开始认为这可能是我问题的主要来源。我想知道是否有人遇到过类似的问题，以及是否有解决此问题的方法。
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