本文介绍了FusedLocationProviderClient:空对象引用上的Location.getLatitude()的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想获取地址城市名称，然后将其放在字符串中，用户应首先打开GPS.我已经尝试了很多代码，但是什么也没发生.直到找到这个，然后我从穿上跟随JavaVersion来获取经度和纬度.
I want to get address City Name and then put it in String, and user should turn on GPS first. I've tried many code but nothing happended. Until I found this, and I following JavaVersion from this answear to get latitude and longitude.
private final String TAG = "MainActivity";
private FusedLocationProviderClient fusedLocationClient;
private final CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
....
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
....
fusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
....
buttonGetLocation.setOnClickListener(view -> {
requestCurrentLocation()
}
....
}
private void requestCurrentLocation() {
Log.d(TAG, "requestCurrentLocation()");
// Request permission
if (ActivityCompat.checkSelfPermission(
this,
Manifest.permission.ACCESS_FINE_LOCATION) ==
PackageManager.PERMISSION_GRANTED) {
// Main code
Task<Location> currentLocationTask = fusedLocationClient.getCurrentLocation(
PRIORITY_HIGH_ACCURACY,
cancellationTokenSource.getToken()
);
currentLocationTask.addOnCompleteListener((new OnCompleteListener<Location>() {
@Override
public void onComplete(@NonNull Task<Location> task) {
String result = "";
if (task.isSuccessful()) {
// Task completed successfully
Location location = task.getResult();
result = "Location (success): " +
location.getLatitude() +
", " +
location.getLongitude();
getAddress(location.getLatitude(), location.getLongitude()); // Get Address
} else {
// Task failed with an exception
Exception exception = task.getException();
result = "Exception thrown: " + exception;
}
Log.d(TAG, "getCurrentLocation() result: " + result);
}
}));
} else {
// TODO: Request fine location permission
Log.d(TAG, "Request fine location permission.");
}
}
private void getAddress(double LATITUDE, double LONGITUDE) {
//Set Address
Geocoder geocoder = new Geocoder(this, Locale.getDefault());
List<Address> addresses = null;
try {
addresses = geocoder.getFromLocation(LATITUDE, LONGITUDE, 1);
} catch (IOException e) {
e.printStackTrace();
}
if (addresses != null && addresses.size() > 0) {
String address = addresses.get(0).getAddressLine(0); // If any additional address line present than only, check with max available address lines by getMaxAddressLineIndex()
String city = addresses.get(0).getLocality();
String state = addresses.get(0).getAdminArea();
String country = addresses.get(0).getCountryName();
String postalCode = addresses.get(0).getPostalCode();
String knownName = addresses.get(0).getFeatureName(); // Only if available else return NULL
Log.d(TAG, "getAddress: address" + address);
Log.d(TAG, "getAddress: city" + city);
Log.d(TAG, "getAddress: state" + state);
Log.d(TAG, "getAddress: postalCode" + postalCode);
Log.d(TAG, "getAddress: knownName" + knownName);
} else {
Log.d(TAG, "Fail get Location!");
}
}
但是随后我在一个空对象引用上得到了Location.getLatitude():
but then I got this Location.getLatitude() on a null object reference :
java.lang.NullPointerException: Attempt to invoke virtual method 'double android.location.Location.getLatitude()' on a null object reference
at com.yayco.rebahan.MainActivity$5.onComplete(MainActivity.java:453)
at com.google.android.gms.tasks.zzj.run(com.google.android.gms:play-services-tasks@@17.2.0:4)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:201)
at android.app.ActivityThread.main(ActivityThread.java:6810)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)
我想念什么?感谢您的帮助.
What i miss? Thanks for help.
推荐答案
您可以尝试以下代码，它对我有用:
you can try this code, it works for me:
private LocationRequest mLocationRequest;
mLocationRequest = LocationRequest.create();
private void requestCurrentLocation() {
Log.d(TAG, "requestCurrentLocation()");
// Request permission
if (ActivityCompat.checkSelfPermission(
this,
Manifest.permission.ACCESS_FINE_LOCATION) ==
PackageManager.PERMISSION_GRANTED) {
// Main code
fusedLocationClient.getLastLocation()
.addOnSuccessListener(new OnSuccessListener<Location>() {
@Override
public void onSuccess(Location location) {
// GPS location can be null if GPS is switched off
if (location != null) {
getLocation(location);
} else {
if (ContextCompat.checkSelfPermission(mContext, android.Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
PermissionUtils.requestPermission((AppCompatActivity) mContext,
LOCATION_PERMISSION_REQUEST_CODE, Manifest.permission.ACCESS_FINE_LOCATION, false);
}
fusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, null);
}
}
})
.addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
Log.e(TAG, "Error trying to get last GPS location");
e.printStackTrace();
}
});
} else {
// TODO: Request fine location permission
Log.d(TAG, "Request fine location permission.");
}
}
private final LocationCallback mLocationCallback = new LocationCallback() {
@Override
public void onLocationResult(LocationResult locationResult) {
super.onLocationResult(locationResult);
if (locationResult.getLastLocation() == null) {
//Log.e(TAG, "onLocationResult: null");
return;
}
getLocation(locationResult.getLastLocation());
}
};
private void getLocation(Location location){
//you will get location here
}
这篇关于FusedLocationProviderClient:空对象引用上的Location.getLatitude()的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！