android - onLocationChanged 在应用程序启动时被多次调用

Question

我写了以下服务，想法是在应用程序启动时将用户位置发送到服务器，当用户移动超过 500m 时，问题是在启动时调用 onLocationChanged 3 次。

我无法理解它从哪里调用它 3 次。请指导我如何解决这个问题。

public class LocationUpdateService extends Service implements
        LocationListener,
        GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener {



    private static final long BACKGROUND_INTERVAL = 60000;

    final private String TAG = LocationUpdateService.class.getSimpleName();
    private LocationRequest mLocationRequest;
    private GoogleApiClient mGoogleApiClient;
    private String LOCATION_PREF = "LOCATION_PREF";



    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.i(TAG, "onStartCommand: ");
        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(BACKGROUND_INTERVAL);
        mLocationRequest.setFastestInterval(30000);
        mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
        mLocationRequest.setSmallestDisplacement(500);
        super.onStartCommand(intent, flags, startId);
        return START_STICKY;
    }

    @Override
    public void onLocationChanged(Location location) {
        Log.i("Location Service", "onLocationChanged: " + location.toString());
        saveLocationandReport(String.valueOf(location.getLatitude()), String.valueOf(location.getLongitude()));
    }

Answer 1

您无法控制onLocationChanged，它由位置服务管理。在您的情况下，您可以设置缓冲/等待时间，如果您在缓冲时间内进行了位置更新，您可以检查其与之前位置更新的准确性比较，哪个最适合使用它。

private int FASTEST_INTERVAL = 1000; // use whatever suits you
private Location currentLocation = null;
private long locationUpdatedAt = Long.MIN_VALUE;

@Override
public void onLocationChanged(Location location) {
    boolean updateLocationandReport = false;
    if(currentLocation == null){
        currentLocation = location;
        locationUpdatedAt = System.currentTimeMillis();
        updateLocationandReport = true;
    } else {
       long secondsElapsed = TimeUnit.MILLISECONDS.toSeconds(System.currentTimeMillis() - locationUpdatedAt);
       if (secondsElapsed >= TimeUnit.MILLISECONDS.toSeconds(FASTEST_INTERVAL)){
            // check location accuracy here
            currentLocation = location;
            locationUpdatedAt = System.currentTimeMillis();
            updateLocationandReport = true;
       }        
    }
    if(updateLocationandReport){
        //  send your location to server
    }
}