使用GPS计算距离时应该使用什么方便的优先级和间隔？

Question

我正在创建计算距离的应用程序。虽然运行我尝试将 priority=PRIORITY_BALANCED_POWER_ACCURACY 设置为 interval = 10 sec。我测试了它，它总是 return 总距离 = 0。问题可能出在优先级和间隔或我的代码上。

应该使用什么最方便的优先级和间隔？

代码

public class MainActivity extends ActionBarActivity implements GoogleApiClient.ConnectionCallbacks,GoogleApiClient.OnConnectionFailedListener,LocationListener {

private GoogleApiClient client;
private LocationRequest mLocationRequest ;
float distanceInMeters = 0;
TextView textView ;
Location A ;
Location B ;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    textView = (TextView) findViewById(R.id.textView);
    A = new Location ("") ;
    B = new Location ("") ;

}
public void activity (View v){
    statusCheck();
    startClient() ;
}
public void clear (View v){
    if(client!=null) {
        client.disconnect();
        textView.setText(distanceInMeters + "  m");
    }
    distanceInMeters = 0 ;
}
public void startClient (){
    if(client==null) {
        client = new GoogleApiClient.Builder(this)
                .addApi(LocationServices.API)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .build();
    }
    client.connect();
}
@Override
protected void onStop() {
    super.onStop();
    if(client!=null) {
        client.disconnect();
    }
}


@Override
public void onConnected(Bundle bundle) {

    mLocationRequest = LocationRequest.create();
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY );
    mLocationRequest.setInterval(10000);
    LocationServices.FusedLocationApi.requestLocationUpdates(client, mLocationRequest, this);

}
public float calculateDistance () {
    if(A==null ||  A.getLatitude()==0){A=B;}

    distanceInMeters = A.distanceTo(B);

    Log.e("A","lat = "+A.getLatitude()+"  lon = "+A.getLongitude() );
    Log.e("B", "lat = " + B.getLatitude() + "  lon = " + B.getLongitude());
    Log.e("distance", "distance = " + distanceInMeters) ;
    A =B ;
    return distanceInMeters ;
}
@Override
public void onLocationChanged(Location location) {
    B.setLatitude(location.getLatitude());
    B.setLongitude(location.getLongitude());
    calculateDistance();
}


@Override
public void onConnectionSuspended(int i) {
}

@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}


public void statusCheck() {
    final LocationManager manager = (LocationManager) getSystemService( Context.LOCATION_SERVICE );

    if ( !manager.isProviderEnabled( LocationManager.GPS_PROVIDER ) ) {
        buildAlertMessageNoGps();

    }


}
private void buildAlertMessageNoGps() {
    final AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setMessage("Your GPS seems to be disabled, do you want to enable it?")
            .setCancelable(false)
            .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                public void onClick(final DialogInterface dialog,  final int id) {
                    startActivity(new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS));
                }
            })
            .setNegativeButton("No", new DialogInterface.OnClickListener() {
                public void onClick(final DialogInterface dialog, final int id) {
                    dialog.cancel();
                }
            });
    final AlertDialog alert = builder.create();
    alert.show();

}
}

Answer 1

在 onCreate 的 Location 构造函数中，将 "gps" 作为参数传递。有关详细信息，请参阅 documentation

使用GPS计算距离时应该使用什么方便的优先级和间隔？

what is convenient priority and interval should be used while calculating distance using GPS?

gps

android

location

google-play-services