问题描述
我正在尝试编写一个可在后台跟踪位置并将数据发送到服务器的应用程序-例如，监视家人的位置。
目前，我正在玩https://github.com/android/location-samples，尤其是LocationUpdatesBackgroundKotlin，这似乎是接收位置更新的最佳方法，但是
在后台接收到大约8-10个位置更新后，状态栏上的gps图标消失，而没有通知应用程序（here是android / phone信息，但我希望该应用程序与Android兼容5.1）。
我想以某种方式知道是否正在接收位置更新，如果它已死，则重新启动它（重新开始接收MyLocationManager的第105行上的fusedLocationClient.requestLocationUpdates的更新有助于接收更多的更新，但是我必须监视眼睛状态）。
有什么出路，还是更可靠的方法？谢谢
附言已经为Android编写了一个星期。
解决方法
为了从应用程序中不断获取位置，您必须使用前台服务，在其中您可以初始化位置管理器并根据已设置的参数不断获取位置更新。另外，请确保您具有背景位置权限，因为这是API级别29之后的要求。以下是如何实现背景位置的最基本流程。确保获得位置许可后启动此服务：
public class MyCustomService extends Service implements
GoogleApiClient.ConnectionCallbacks,GoogleApiClient.OnConnectionFailedListener {
private GoogleApiClient mGoogleApiClient;
private PowerManager.WakeLock mWakeLock;
private LocationRequest mLocationRequest;
private boolean mInProgress;
private Boolean servicesAvailable = false;
@Override
public IBinder onBind(Intent arg0) {
return null;
}
private static final int UPDATE_INTERVAL_IN_SECONDS = 120;
private static final int MILLISECONDS_PER_SECOND = 1000;
public static final long UPDATE_INTERVAL = MILLISECONDS_PER_SECOND * UPDATE_INTERVAL_IN_SECONDS;
private static final int FASTEST_INTERVAL_IN_SECONDS = 60;
public static final long FASTEST_INTERVAL = MILLISECONDS_PER_SECOND * FASTEST_INTERVAL_IN_SECONDS;
@Override
public void onCreate() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
startForegroundService();
}
mInProgress = false;
mLocationRequest = LocationRequest.create();
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
mLocationRequest.setInterval(UPDATE_INTERVAL);
mLocationRequest.setFastestInterval(FASTEST_INTERVAL);
mLocationRequest.setSmallestDisplacement(100);
servicesAvailable = servicesConnected();
/*
* Create a new location client,using the enclosing class to
* handle callbacks.
*/
setUpLocationClientIfNeeded();
super.onCreate();
}
private void setUpLocationClientIfNeeded() {
if (mGoogleApiClient == null)
buildGoogleApiClient();
}
/*
* Create a new location client,using the enclosing class to
* handle callbacks.
*/
protected synchronized void buildGoogleApiClient() {
this.mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
private boolean servicesConnected() {
// Check that Google Play services is available
int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
// If Google Play services is available
if (ConnectionResult.SUCCESS == resultCode) {
return true;
} else {
return false;
}
}
/* Used to build and start foreground service. */
private void startForegroundService() {
Intent notificationIntent = new Intent(this,HomeActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this,notificationIntent,0);
String CHANNEL_ID = "1";
NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
NotificationCompat.Builder builder = new NotificationCompat.Builder(this,CHANNEL_ID)
.setSmallIcon(R.drawable.noti_icon)
.setPriority(Notification.PRIORITY_LOW)
.setOngoing(true)
.setAutoCancel(false)
.setContentTitle("ServiceTitle")
.setContentText("Service Reason text")
.setTicker("TICKER")
.setChannelId(CHANNEL_ID)
.setVibrate(new long[]{0L})
.setContentIntent(pendingIntent);
Notification notification = builder.build();
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
NotificationChannel channel = new NotificationChannel(CHANNEL_ID,"NOTIFICATION_CHANNEL_NAME",NotificationManager.IMPORTANCE_HIGH);
channel.setDescription("NOTIFICATION_CHANNEL_DESC");
channel.enableVibration(false);
channel.setLockscreenVisibility(Notification.VISIBILITY_PUBLIC);
notificationManager.createNotificationChannel(channel);
}
startForeground(123,notification);
}
@Override
public void onDestroy() {
super.onDestroy();
this.mInProgress = false;
if (this.servicesAvailable && this.mGoogleApiClient != null) {
this.mGoogleApiClient.unregisterConnectionCallbacks(this);
this.mGoogleApiClient.unregisterConnectionFailedListener(this);
this.mGoogleApiClient.disconnect();
// Destroy the current location client
this.mGoogleApiClient = null;
}
if (this.mWakeLock != null) {
this.mWakeLock.release();
this.mWakeLock = null;
}
}
@Override
public int onStartCommand(Intent intent,int flags,int startId) {
super.onStartCommand(intent,flags,startId);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
startForegroundService();
}
setUpLocationClientIfNeeded();
if (!mGoogleApiClient.isConnected() || !mGoogleApiClient.isConnecting() && !mInProgress) {
mInProgress = true;
mGoogleApiClient.connect();
}
return START_STICKY;
}
@Override
public void onConnected(@Nullable Bundle bundle) {
Intent intent = new Intent(this,LocationReceiver.class);
PendingIntent pendingIntent = PendingIntent
.getBroadcast(this,54321,intent,PendingIntent.FLAG_CANCEL_CURRENT);
if (ActivityCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this,Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return;
}
if (this.mGoogleApiClient != null)
LocationServices.FusedLocationApi.requestLocationUpdates(this.mGoogleApiClient,mLocationRequest,pendingIntent);
}
@Override
public void onConnectionSuspended(int i) {
// Turn off the request flag
mInProgress = false;
// Destroy the current location client
mGoogleApiClient = null;
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
mInProgress = false;
/*
* Google Play services can resolve some errors it detects.
* If the error has a resolution,try sending an Intent to
* start a Google Play services activity that can resolve
* error.
*/
if (connectionResult.hasResolution()) {
// If no resolution is available,display an error dialog
} else {
}
}
}
这是位置接收器类，您还需要在Androidmanifest文件中注册
public class LocationReceiver extends BroadcastReceiver {
private String TAG = "LOCATION RECEIVER";
private LocationResult mLocationResult;
private Context context;
Location mLastLocation;
@Override
public void onReceive(Context context,Intent intent) {
// Need to check and grab the Intent's extras like so
this.context = context;
if (LocationResult.hasResult(intent)) {
this.mLocationResult = LocationResult.extractResult(intent);
if (mLocationResult.getLocations().get(0).getAccuracy() < 100) {
// DO WHATEVER YOU WANT WITH LOCATION
}
}
}
}
所需的权限：
<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
<uses-permission android:name="android.permission.ACCESS_GPS" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION"/>
注意：以上代码中的某些方法（如FusedLocationApi和isGooglePlayServicesAvailable）已弃用
,对于Android 5 Lollipop来说，最好使用第三方库来接收免费的位置信息（更可靠），即使用io.nlopez.smartlocation.SmartLocation中的'io.nlopez.smartlocation:library:3.3.3'（如here所述）如Rudrik Patel所述，具有前台服务。就像魅力一样。