我正在尝试构建一个使用GoogleClientApi和LocationServices请求当前位置的应用程序，但即使我启用了WiFi，移动数据和GPS，在所有相同的设备上对其进行了测试，该位置始终为空
manifest.xml的权限：
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
的活动：
public class FindStation extends Fragment implements GoogleApiClient.ConnectionCallbacks,GoogleApiClient.OnConnectionFailedListener,com.google.android.gms.location.LocationListener
{
public static FragmentManager fragmentManager;
Button goButton;
Spinner spinner;
SupportMapFragment mapFragment;
GoogleMap map;
List<Stations> stationsList;
ArrayList<String> stationsAddresses;
private static View view;
ArrayList<MarkerOptions> markers;
GoogleApiClient mGoogleApiClient;
LocationServices locationServices;
Location location;
private static String TAG="FIND_STATION";
Context context;
LocationRequest mLocationRequest;
LocationListener locationListener;
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
context= getActivity();
locationListener=this;
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(10000);
mLocationRequest.setFastestInterval(5000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
mLocationRequest.setSmallestDisplacement(10);
/*mGoogleApiClient = new GoogleApiClient.Builder(getActivity())
.addApi(LocationServices.API)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();*/
buildGoogleApiClient();
if (view != null) {
ViewGroup parent = (ViewGroup) view.getParent();
if (parent != null)
parent.removeView(view);
}
try {
view = inflater.inflate(R.layout.activity_find_station, container, false);
} catch (InflateException e) {
}
inflater.inflate(R.layout.activity_find_station,container,false);
stationsAddresses = new ArrayList<>();
goButton= (Button) view.findViewById(R.id.button);
//goButton.setVisibility(View.INVISIBLE);
spinner= (Spinner) view.findViewById(R.id.spinner);
stationsList = Stations.listAll(Stations.class);
markers = new ArrayList<>();
for (int i = 0; i <stationsList.size() ; i++) {
stationsAddresses.add(stationsList.get(i).getStationLocation());
markers.add(new MarkerOptions().position(new LatLng(stationsList.get(i).getStationLat(), stationsList.get(i).getStationLong())).title(stationsList.get(i).getStationName()));
}
goButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//location= LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
}
});
try {
initialize();
} catch (Exception e) {
e.printStackTrace();
}
try {
// map.setMyLocationEnabled(true);
} catch (Exception e) {
e.printStackTrace();
}
/*thread = new Thread(new MyThread());
thread.start();*/
return view;
}
private void initialize() {
if (map==null) {
Fragment fragment= getChildFragmentManager().findFragmentById(R.id.map);
mapFragment= (SupportMapFragment) fragment;
map=mapFragment.getMap();
for (int i = 0; i <markers.size() ; i++) {
map.addMarker(markers.get(i));
}
// check if map is created successfully or not
if (map==null) {
Toast.makeText(super.getActivity(),
"Sorry! unable to create maps", Toast.LENGTH_SHORT)
.show();
}
}
}
public void onDestroyView() {
super.onDestroyView();
android.support.v4.app.FragmentManager fm = getActivity().getSupportFragmentManager();
SupportMapFragment fragment = (SupportMapFragment) fm.findFragmentById(R.id.map);
if (fragment!=null) {
android.support.v4.app.FragmentTransaction ft = fm.beginTransaction();
ft.remove(fragment);
ft.commit();
}
}
@Override
public void onConnected(Bundle bundle) {
location= LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
if (location!=null){
Log.d(TAG,location.toString());
CameraUpdate update = CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(),location.getLongitude()),3f);
map.animateCamera(update);
}
Log.d(TAG,"connected");
}
@Override
public void onConnectionSuspended(int i) {
Log.d(TAG,"connection suspended "+String.valueOf(i));
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
Log.d(TAG,"connection failed");
}
@Override
public void onLocationChanged(Location location) {`enter code here`
Log.d(TAG,location.toString());
this.location=location;
if (location!=null) {
CameraUpdate update = CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(), location.getLongitude()), 3f);
map.animateCamera(update);
Log.d(TAG, "camera updated to new position");
goButton.setVisibility(View.VISIBLE);
}
}
@Override
public void onStart() {
super.onStart();
mGoogleApiClient.connect();
Log.d(TAG,"connect() was called");
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(context)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
}
奇怪的是，onConnect（）方法被调用，但之后，Location始终为null，并且永远不会调用onLocationChanged（）
使用地图，我尝试启用我的位置，当你在右上角有一个按钮返回位置并为相机设置动画时它就可以正常工作。
更新1
更新了onConnected（）方法并使其请求位置更新
public void onConnected(Bundle bundle) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, locationListener);
if (location!=null){
Log.d(TAG,location.toString());
CameraUpdate update = CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(),location.getLongitude()),3f);
map.animateCamera(update);
}
Log.d(TAG,"connected");}
然后用一个按钮调用lastKnownLocation（），因为onLocationChanged（）没有被调用，仍然返回的Location是null
更新2：
完全相同的代码适用于Android 5.0.1并且运行良好 所有其他设备都在android 2.3.7,4.0.1上，没有一个工作，
有关Android API的位置有何不同之处？
答案 0 :(得分：4)
您需要调用requestLocationUpdates()才能注册侦听器并调用onLocationChanged()。
请务必尽快取消注册听众，以免电池耗尽过多。
另请注意，getLastLocation（）方法可以并且将返回null。主要问题是它没有向操作系统提示请求新的位置锁定，而只是检查是否存在来自某个其他应用程序位置请求的最后已知位置。如果最近没有其他应用程序发出了位置请求，那么您将获得一个返回给您的空位置。
保证实际获得位置的唯一方法是请求一个，这是通过调用requestLocationUpdates（）完成的。
以下是一个可供参考的工作示例：
public class MainActivity extends FragmentActivity
implements OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener,
LocationListener {
private GoogleMap map;
private LocationRequest mLocationRequest;
private GoogleApiClient mGoogleApiClient;
private Location mLastLocation;
private Marker marker;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
protected void onResume() {
super.onResume();
buildGoogleApiClient();
mGoogleApiClient.connect();
if (map == null) {
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
}
@Override
public void onMapReady(GoogleMap retMap) {
map = retMap;
setUpMap();
}
public void setUpMap(){
map.setMapType(GoogleMap.MAP_TYPE_HYBRID);
map.setMyLocationEnabled(true);
}
@Override
protected void onPause(){
super.onPause();
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
protected synchronized void buildGoogleApiClient() {
Toast.makeText(this, "buildGoogleApiClient", Toast.LENGTH_SHORT).show();
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
@Override
public void onConnected(Bundle bundle) {
Toast.makeText(this,"onConnected",Toast.LENGTH_SHORT).show();
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
//mLocationRequest.setSmallestDisplacement(0.1F);
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
@Override
public void onConnectionSuspended(int i) {
Toast.makeText(this,"onConnectionSuspended",Toast.LENGTH_SHORT).show();
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
Toast.makeText(this,"onConnectionFailed",Toast.LENGTH_SHORT).show();
}
@Override
public void onLocationChanged(Location location) {
mLastLocation = location;
//remove previous current location Marker
if (marker != null){
marker.remove();
}
double dLatitude = mLastLocation.getLatitude();
double dLongitude = mLastLocation.getLongitude();
marker = map.addMarker(new MarkerOptions().position(new LatLng(dLatitude, dLongitude))
.title("My Location").icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_RED)));
map.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(dLatitude, dLongitude), 8));
}
}
还有一件事，如果您的地图位于片段中，则无需使用嵌套的SupportMapFragment。你可以让你的Fragment扩展SupportMapFragment。这样就无需使用嵌套的Fragment，甚至不需要为任何布局xml充气，这里有一个简单的例子：
public class MapTabFragment extends SupportMapFragment
implements OnMapReadyCallback {
private GoogleMap mMap;
private Marker marker;
public MapTabFragment() {
}
@Override
public void onResume() {
super.onResume();
setUpMapIfNeeded();
}
private void setUpMapIfNeeded() {
if (mMap == null) {
getMapAsync(this);
}
}
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
setUpMap();
}
private void setUpMap() {
mMap.setMyLocationEnabled(true);
mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
mMap.getUiSettings().setMapToolbarEnabled(false);
mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
@Override
public void onMapClick(LatLng point) {
//remove previously placed Marker
if (marker != null) {
marker.remove();
}
//place marker where user just clicked
marker = mMap.addMarker(new MarkerOptions().position(point).title("Marker")
.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA)));
}
});
}
}