我无法在打开地图活动记录后立即获取当前位置。 尽管它用蓝点标记显示当前位置。
我看到一条异常消息：java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法"double android.location.Location.getLatitude((">
获取坐标需要花费大量时间。为此，我必须移动手机并等待。
这是我的代码：
if (Build.VERSION.SDK_INT < 25) {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION) !=
PackageManager.PERMISSION_GRANTED) {
// Ask for permission
ActivityCompat.requestPermissions(this, new String[]
{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION) !=
PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(this, new String[]
{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
}
} else {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0,
0, locationListener);
lastKnownLocation =
locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
try {
pDialog.hide();
locate = new LatLng(lastKnownLocation.getLatitude(),
lastKnownLocation.getLongitude());
mMap.clear();
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(locate, 13));
originMarkers.add(mMap.addMarker(new MarkerOptions()
.title("Your Location")
.position(locate)));
origin_lati = "" + lastKnownLocation.getLatitude();
origin_longi = "" + lastKnownLocation.getLongitude();
Log.e("Lati Longi", origin_lati+", "+origin_longi);
}catch (Exception e){
Log.e("Exception", e.toString());
}
}
}
使用这个：
首先创建谷歌 API 客户端：
/**
* Builds a GoogleApiClient.
* Uses the addApi() method to request the Google Places API and the Fused Location Provider.
*/
private synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.enableAutoManage(this /* FragmentActivity */,
this /* OnConnectionFailedListener */)
.addConnectionCallbacks(this)
.addApi(LocationServices.API)
.addApi(Places.GEO_DATA_API)
.addApi(Places.PLACE_DETECTION_API)
.build();
createLocationRequest();
}
/**
* Sets up the location request.
*/
private void createLocationRequest() {
mLocationRequest = new LocationRequest();
/*
* Sets the desired interval for active location updates. This interval is
* inexact. You may not receive updates at all if no location sources are available, or
* you may receive them slower than requested. You may also receive updates faster than
* requested if other applications are requesting location at a faster interval.
*/
mLocationRequest.setInterval(UPDATE_INTERVAL_IN_MILLISECONDS);
/*
* Sets the fastest rate for active location updates. This interval is exact, and your
* application will never receive updates faster than this value.
*/
mLocationRequest.setFastestInterval(FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
}
然后获取位置：
/**
* Gets the current location of the device and starts the location update notifications.
*/
private void getDeviceLocation() {
/*
* Request location permission, so that we can get the location of the
* device. The result of the permission request is handled by a callback,
* onRequestPermissionsResult.
*/
if (ContextCompat.checkSelfPermission(this.getApplicationContext(),
android.Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
mLocationPermissionGranted = true;
} else {
ActivityCompat.requestPermissions(this,
new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION);
}
/*
* Get the best and most recent location of the device, which may be null in rare
* cases when a location is not available.
* Also request regular updates about the device location.
*/
if (mLocationPermissionGranted) {
mCurrentLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
mLocationRequest, this);
}
}
/**
* Handles the result of the request for location permissions.
*/
@Override
public void onRequestPermissionsResult(int requestCode,
@NonNull String permissions[],
@NonNull int[] grantResults) {
mLocationPermissionGranted = false;
switch (requestCode) {
case PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
mLocationPermissionGranted = true;
}
}
}
}
现在，mCurrentLocation让您当前的位置在您想要的任何地方使用它。
从你的onCreate构建Api客户端：
// Build the Play services client for use by the Fused Location Provider and the Places API.
buildGoogleApiClient();
mGoogleApiClient.connect();
然后在您的简历中：
@Override
protected void onResume() {
super.onResume();
if (mGoogleApiClient.isConnected()) {
getDeviceLocation();
}
}
声明以下全局变量：
// The entry point to Google Play services, used by the Places API and Fused Location Provider.
private GoogleApiClient mGoogleApiClient;
// A request object to store parameters for requests to the FusedLocationProviderApi.
private LocationRequest mLocationRequest;
// The desired interval for location updates. Inexact. Updates may be more or less frequent.
private static final long UPDATE_INTERVAL_IN_MILLISECONDS = 10000;
// The fastest rate for active location updates. Exact. Updates will never be more frequent
// than this value.
private static final long FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS =
UPDATE_INTERVAL_IN_MILLISECONDS / 2;
private static final int PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1;
private boolean mLocationPermissionGranted;
// The geographical location where the device is currently located.
private Location mCurrentLocation;
我只需稍作修改即可获得解决方案
String provider;
provider=locationManager.getProvider(LocationManager.NETWORK_PROVIDER).getName();
if (Looper.myLooper() == null) {
Looper.prepare();
}
locationManager.requestSingleUpdate(provider, locationListener, Looper.myLooper());
locationManager.requestLocationUpdates(provider,0,0, locationListener);
currentLocation = locationManager.getLastKnownLocation(provider);
try {
pDialog.hide();
locate = new LatLng(currentLocation.getLatitude(), currentLocation.getLongitude());
mMap.clear();
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(locate, 13));
originMarkers.add(mMap.addMarker(new MarkerOptions()
.title("Your Location")
.position(locate)));
origin_lati = "" + currentLocation.getLatitude();
origin_longi = "" + currentLocation.getLongitude();
Log.e("Lati Longi", origin_lati+", "+origin_longi);
}catch (Exception e){
ActivityCompat.requestPermissions(this, new String[]
{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
Log.e("Exception", e.toString());
}