在后台接收位置更新的最佳方法是什么？

Question

我正试图编写一个应用程序来跟踪背景中的位置，并将数据发送到服务器--例如，监视我的家人在哪里。

目前，我正在使用https://github.com/android/location-samples，特别是LocationUpdatesBackgroundKotlin，这似乎是接收位置更新的最佳方式，但是

在收到背景中的8-10个位置更新后，状态栏上的gps图标在没有通知应用程序的情况下死亡(这里是android/phone信息，但我希望该应用程序与Android5.1兼容)。

我想知道是否是活着地接收位置更新，如果它死了就重新启动它(用fusedLocationClient.requestLocationUpdates重新启动MyLocationManager的第105行可以帮助接收进一步的更新，但是我必须用眼睛监视状态)。

有没有什么出路，或者更可靠的方法？谢谢。

P.S.已经为android写了一个星期了。

Answer 1

对于Android5Lolliop来说，使用第三方库(更稳定得多)接收基站位置(即io.nlopez.smartlocation.SmartLocation from 'io.nlopez.smartlocation:library:3.3.3' )和前台服务(如Rudrik Patel所提到的)是更好的(更稳定的)。就像一种魅力。

Answer 2

为了不断地从应用程序中获取位置，您必须使用前台服务，您可以在其中初始化位置管理器，并根据已设置的参数不断地获取位置更新。另外，确保您有背景位置权限，因为它是在API级别29之后的要求。以下是如何实现这一目标的基本流程。请确保在获得“位置”权限后启动此服务：

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, 0, 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 {

        }
    }
}

以下是您需要在Android清单文件中注册的Location接收器类

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
            }
        }
    }
}

所需许可：

<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:上述代码中的一些方法(如FusedLocationApi和isGooglePlayServicesAvailable )是不推荐的。