Android 地图应用程序并不总是转到当前位置

Question

我以为我已经解决了（在其他人的帮助下）。我希望我的地图应用程序直接转到我当前的位置，但超过 50% 的时间，它最初会显示上次使用它的位置，我必须单击“当前位置的中心”按钮（右上角）让它去那里。我能做些什么来让这项工作 100% 完成？相关代码如下。感谢您的帮助。

public class LocateMe 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_locate_me);
    setUpMapIfNeeded();

    if (mMap != null) {
        mMap.setMyLocationEnabled(true);
        mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);

        // -------
        LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        Criteria criteria = new Criteria();

        try {
            Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
            if (location != null)
            {
                mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
                        new LatLng(location.getLatitude(), location.getLongitude()), 13));

                CameraPosition cameraPosition = new CameraPosition.Builder()
                        .target(new LatLng(location.getLatitude(), location.getLongitude()))      // Sets the center of the map to location user
                        .zoom(17)                   // Sets the zoom
                        .bearing(00)                // Sets the orientation of the camera to north
                        .tilt(00)                   // Sets the tilt of the camera to 0 degrees
                        .build();                   // Creates a CameraPosition from the builder
                mMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));

            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        // ---
    }
}

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

/**
 * Sets up the map if it is possible to do so (i.e., the Google Play services APK is correctly
 * installed) and the map has not already been instantiated.. This will ensure that we only ever
 * call {@link #setUpMap()} once when {@link #mMap} is not null.
 * <p/>
 * If it isn't installed {@link SupportMapFragment} (and
 * {@link com.google.android.gms.maps.MapView MapView}) will show a prompt for the user to
 * install/update the Google Play services APK on their device.
 * <p/>
 * A user can return to this FragmentActivity after following the prompt and correctly
 * installing/updating/enabling the Google Play services. Since the FragmentActivity may not
 * have been completely destroyed during this process (it is likely that it would only be
 * stopped or paused), {@link #onCreate(Bundle)} may not be called again so we should call this
 * method in {@link #onResume()} to guarantee that it will be called.
 */
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();
        // Check if we were successful in obtaining the map.
        if (mMap != null) {
            setUpMap();
        }
    }
}

/**
 * This is where we can add markers or lines, add listeners or move the camera. In this case, we
 * just add a marker near Africa.
 * <p/>
 * This should only be called once and when we are sure that {@link #mMap} is not null.
 */
private void setUpMap()
{
    mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
}
}

Answer 1

您可以实现LocationListener，它会在设备获得新的位置数据时通知。

public class LocateMe extends FragmentActivity implements LocationListener {

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_locate_me);
        setUpMapIfNeeded();

        if (mMap != null) {
            mMap.setMyLocationEnabled(true);
            mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);

        // -------
            LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 10, this);
            Criteria criteria = new Criteria();

            try {
                Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
                if (location != null) {
                    mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
                    new LatLng(location.getLatitude(), location.getLongitude()), 13));

                    CameraPosition cameraPosition = new CameraPosition.Builder()
                    .target(new LatLng(location.getLatitude(), location.getLongitude()))      // Sets the center of the map to location user
                    .zoom(17)                   // Sets the zoom
                    .bearing(00)                // Sets the orientation of the camera to north
                    .tilt(00)                   // Sets the tilt of the camera to 0 degrees
                    .build();                   // Creates a CameraPosition from the builder
                    mMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));

                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        // ---
        }
    }

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

/**
 * Sets up the map if it is possible to do so (i.e., the Google Play services APK is correctly
 * installed) and the map has not already been instantiated.. This will ensure that we only ever
 * call {@link #setUpMap()} once when {@link #mMap} is not null.
 * <p/>
 * If it isn't installed {@link SupportMapFragment} (and
 * {@link com.google.android.gms.maps.MapView MapView}) will show a prompt for the user to
 * install/update the Google Play services APK on their device.
 * <p/>
 * A user can return to this FragmentActivity after following the prompt and correctly
 * installing/updating/enabling the Google Play services. Since the FragmentActivity may not
 * have been completely destroyed during this process (it is likely that it would only be
 * stopped or paused), {@link #onCreate(Bundle)} may not be called again so we should call this
 * method in {@link #onResume()} to guarantee that it will be called.
 */
    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();
            // Check if we were successful in obtaining the map.
            if (mMap != null) {
                setUpMap();
            }
        }
    }

/**
 * This is where we can add markers or lines, add listeners or move the camera. In this case, we
 * just add a marker near Africa.
 * <p/>
 * This should only be called once and when we are sure that {@link #mMap} is not null.
 */
    private void setUpMap() {
        mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
    }

    @Override
    public void onLocationChanged(Location location) {
        LatLng latLng = new LatLng(location.getLatitude, location.getLongitude);
        mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
        mMap.animateCamera(CameraUpdateFactory.zoomTo(17));
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {

    }

    @Override
    public void onProviderEnabled(String provider) {

    }

    @Override
    public void onProviderDisabled(String provider) {

    }
}

这将在每次更改位置时更新您的地图，因此当您启动应用程序时，相机将在设备获得新位置后立即更新，此代码未经测试，因此可能需要进行一些更改，但我希望对你有帮助。