放大当前用户位置显示

问题描述

我使用的是谷歌地图Android版V2。我想显示当前用户的位置，并放大就可以了。这里是code。在 FragmentActivity ：

I'm using the Google Maps for Android v2. I would like to display the current user location and zoom on it.Here is the code in the FragmentActivity:

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

    mMap = ((SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.mapFragment_mapActivity)).getMap();
    if (mMap == null) {
        Toast.makeText(this, R.string.mapCreationProblem, Toast.LENGTH_LONG)
                .show();
        finish();
        return;
    }
    mMap.setMyLocationEnabled(true);
    Location currentLocation = mMap.getMyLocation();
    if(currentLocation!=null){
       LatLng currentCoordinates = new LatLng(
                            currentLocation.getLatitude(),
                            currentLocation.getLongitude());
       mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(currentCoordinates, 10));
    }
}

地图工作正常，也是蓝点的当前位置的作品。但似乎 currentLocation 总是空。因此，我不能放大的当前位置。

The map works fine and also the blue dot on the current location works. But it seems currentLocation is always null. So I cannot zoom on the current location.

任何谁知道这是为什么吗？

Anyone who knows why, please?

推荐答案

下面是getMyLocation的）与寻找的人的位置额外保护的实现（。我只是有这个在管理该地图碎片的活动。

Here is an implementation of getMyLocation() with added protection for finding the persons location. I just have this in the activity that manages the map fragment.

private Location getMyLocation() {
    // Get location from GPS if it's available
    LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
    Location myLocation = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);

    // Location wasn't found, check the next most accurate place for the current location
    if (myLocation == null) {
        Criteria criteria = new Criteria();
        criteria.setAccuracy(Criteria.ACCURACY_COARSE);
        // Finds a provider that matches the criteria
        String provider = lm.getBestProvider(criteria, true);
        // Use the provider to get the last known location
        myLocation = lm.getLastKnownLocation(provider);
    }

    return myLocation;
}

谢谢，DMAN

Thanks,DMan

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