android - Android Maps Api V2 中是否有类似于 onFirstFix 方法的功能？

Question

我可以通过 setMyLocationEnabled 在新的 Maps Api 中启用 myLocation View .

Api 的第一个版本有一个方法 runOnFirstFix这使我能够在找到位置后将 map 动画化到用户位置。我在 Api 版本 2 中找不到类似的监听器或位置。

是否有一种解决方案可以在用户定位后执行操作？

Answer 1

Google Maps Android API V2 有一个 LocationSource。来自文档:

“GoogleMap 对象为其 my-location 层提供了一个内置位置提供程序，但它可以替换为另一个实现此接口(interface)的提供程序。”

LocationSource

我想您需要将它与 LocationSource.OnLocationChangedListener 结合使用

更新

想通了。如果您想执行类似于 runOnFirstFix 的操作，这里有一个基本示例，它会等待用户的位置可用，然后将 map 设置为以用户位置为中心的动画。

public class MyLocationMapFragmentActivity extends FragmentActivity implements LocationListener, LocationSource
{
/**
 * Note that this may be null if the Google Play services APK is not available.
 */
private GoogleMap mMap;

private OnLocationChangedListener mListener;
private LocationManager locationManager;

private Context mContext;

@Override
protected void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);

    setContentView(R.layout.basic_map);

    this.mContext = this;

    locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

    //You may want to pass a different provider in as the first arg here
    //depending on the location accuracy that you desire
    //see LocationManager.getBestProvider()
    Criteria locationCriteria = new Criteria();
    locationCriteria.setAccuracy(Criteria.ACCURACY_FINE);
    locationManager.requestLocationUpdates(locationManager.getBestProvider(locationCriteria, true), 1L, 2F, this);

    setUpMapIfNeeded();
}

@Override
public void onPause()
{
    if(locationManager != null)
    {
        locationManager.removeUpdates(this);
    }

    super.onPause();
}

@Override
public void onResume()
{
    super.onResume();

    setUpMapIfNeeded();

    if(locationManager != null)
    {
        mMap.setMyLocationEnabled(true);
    }
}


/**
 * 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 Activity after following the prompt and correctly
 * installing/updating/enabling the Google Play services. Since the Activity 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.basicMap)).getMap();
        // Check if we were successful in obtaining the map.

        //This is how you register the LocationSource
        mMap.setLocationSource(this);

        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.setMyLocationEnabled(true);
}

@Override
public void activate(OnLocationChangedListener listener) 
{
    mListener = listener;
}

@Override
public void deactivate() 
{
    mListener = null;
}

@Override
public void onLocationChanged(Location location) 
{
    if( mListener != null )
    {
        mListener.onLocationChanged( location );

        //Move the camera to the user's location once it's available!
        mMap.animateCamera(CameraUpdateFactory.newLatLng(new LatLng(location.getLatitude(), location.getLongitude())));
    }
}

@Override
public void onProviderDisabled(String provider) 
{
    // TODO Auto-generated method stub
    Toast.makeText(this, "provider disabled", Toast.LENGTH_SHORT).show();
}

@Override
public void onProviderEnabled(String provider) 
{
    // TODO Auto-generated method stub
    Toast.makeText(this, "provider enabled", Toast.LENGTH_SHORT).show();
}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) 
{
    // TODO Auto-generated method stub
    Toast.makeText(this, "status changed", Toast.LENGTH_SHORT).show();
}
}

更新 2

如果您有兴趣在用户位置离开屏幕时将 map 居中放置在用户位置上(就像旧 API 中的 MyLocationOverlay 所做的那样)，请参阅 this answer

或这篇博文:Google Maps Android API V2 MyLocation LocationSource and event handling