打开我的应用程序时，Android Studio Google Maps如何将相机重定向到我的当前位置

Question

The Camera Animation is not working its not directing to my location when I open my Application and it does not add a Marker either

 public class MapsActivity extends FragmentActivity {

private GoogleMap mMap; // Might be null if Google Play services APK is not available.



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);

}


@Override
protected void onResume() {
    super.onResume();
    setUpMapIfNeeded();
}

Here it wont direct my camera in my current location. When I open my application it starts at the center of the map not my location

private void setUpMapIfNeeded() {
    // Do a null check to confirm that we have not already instantiated the map.
    if (mMap == null) {
        // Try to obtain the map from the SupportMapFragment.
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                .getMap();
        mMap.setMyLocationEnabled(true);
        // Check if we were successful in obtaining the map.
        if (mMap != null) {
            setUpMapIfNeeded();

        }
    }

}

private void setUpMap() {
    mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker").snippet("Snippet"));
    mMap.setMyLocationEnabled(true);
    LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    Criteria criteria = new Criteria();
    String provider = locationManager.getBestProvider(criteria, true);
    Location location = locationManager.getLastKnownLocation(provider);

    if (location != null) {

        LatLng target = new LatLng(location.getLatitude(), location.getLongitude());
        CameraPosition position = this.mMap.getCameraPosition();

        CameraPosition.Builder builder = new CameraPosition.Builder();
        builder.zoom(15);
        builder.target(target);

        this.mMap.animateCamera(CameraUpdateFactory.newCameraPosition(builder.build()));
        mMap.addMarker(new MarkerOptions().position(new LatLng(location.getLatitude(), location.getLongitude())).title("You are here!").snippet("Consider yourself located"));
    }
}
}

Answer 1

You have few huge super basic errors:

First onResume is only called when activity in the baground comes to the foreground. Put setUpMapIfNeeded() Inside onCreate as well.

Second in your function setUpMapIfNeeded() in the last if statement instead of putting setUpMap() you put setUpMapIfNeeded() change that and it should work.

public class MapsActivity extends  FragmentActivity {

private GoogleMap mMap; // Might be null if Google Play services APK is not available.

Here is your code modified:

Part 1

@Override
 protected void onCreate(Bundle 
savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
setUpMapIfNeeded();

}


@Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
}

Part 2

private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
    // Try to obtain the map from the SupportMapFragment.
    mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
            .getMap();
   mMap.setMyLocationEnabled(true);
    // Check if we were successful in obtaining the map.
    if (mMap != null) {
        setUpMap();

    }
    }

}

private void setUpMap() {
mMap.addMarker(new.MarkerOptions().position(new LatLng(0, 0)).title("Marker").snippet("Snippet"));
mMap.setMyLocationEnabled(true);
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
String provider = locationManager.getBestProvider(criteria, true);
Location location = locationManager.getLastKnownLocation(provider);

if (location != null) {

    LatLng target = new LatLng(location.getLatitude(), location.getLongitude());
    CameraPosition position = this.mMap.getCameraPosition();

    CameraPosition.Builder builder = new CameraPosition.Builder();
    builder.zoom(15);
    builder.target(target);

    this.mMap.animateCamera(CameraUpdateFactory.newCameraPosition(builder.build()));
    mMap.addMarker(new MarkerOptions().position(new LatLng(location.getLatitude(), location.getLongitude())).title("You are here!").snippet("Consider yourself located"));
}
}
}

Answer 2

private void setUpMapIfNeeded() {
    if (mMap == null) {
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
        if (mMap != null) {
            setUpMap();
        }
    }
}

private void setUpMap() {
    mMap.setMyLocationEnabled(true);
    mMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() {
            @Override
            public void onMyLocationChange(Location location) {
                LatLng l = new LatLng(location.getLatitude(), location.getLongitude());
                mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(l, mMap.getCameraPosition().zoom));
            }
        });
}

Just change this 2 methods