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我在我的應用程序中實現fusedLocationAPI。對於具有> =棉花糖的Android手機，我將加入權限。問題是在安裝後第一次，lat和long值返回爲null。但下次啓動應用程序後，它工作正常。下面我張貼我的代碼。請看一看。FusedLocationAPI在添加權限後第一次返回null
裏面的onCreate（）：
manager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
statusOfGPS = manager.isProviderEnabled(LocationManager.GPS_PROVIDER);
buildGoogleApiClient();
checkPermission();
if (!mGoogleApiClient.isConnected()) {
mGoogleApiClient.connect();
}
if (!statusOfGPS) {
displayPromptForEnablingGPS(MainActivity.this);
}
其他方法：
@Override
public void onConnected(@Nullable Bundle bundle) {
checkPermission();
mLocationRequest = LocationRequest.create();
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
// Update location every second
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return;
}
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
mGoogleApiClient);
if (mLastLocation != null) {
lat = mLastLocation.getLatitude();
lon = mLastLocation.getLongitude();
if (!String.valueOf(lat).equals("0.0")){
latitudeVal = mLastLocation.getLatitude();
longitudeVal = mLastLocation.getLongitude();
Log.e("Lat and Lng", String.valueOf(latitudeVal)+ longitudeVal);
}
}
}
@Override
public void onConnectionSuspended(int i) {
}
synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
}
public void displayPromptForEnablingGPS(final Activity activity) {
final android.support.v7.app.AlertDialog.Builder builder = new android.support.v7.app.AlertDialog.Builder(activity);
final String action = Settings.ACTION_LOCATION_SOURCE_SETTINGS;
final String message = "Do you want open GPS setting?";
builder.setMessage(message)
.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface d, int id) {
activity.startActivity(new Intent(action));
d.dismiss();
}
})
.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface d, int id) {
d.cancel();
}
});
builder.create().show();
}
private void requestPermission() {
ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION}, 1);
}
private void showMessageOKCancel(String message, DialogInterface.OnClickListener okListener) {
new AlertDialog.Builder(MainActivity.this)
.setMessage(message)
.setPositiveButton("OK", okListener)
.setNegativeButton("Cancel", null)
.create()
.show();
}
String[] permissions = new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION };
Activity activity =this;
Context context = this;
private boolean checkPermission() {
int result;
List<String> listPermissionsNeeded = new ArrayList<>();
for (String p:permissions) {
result = ContextCompat.checkSelfPermission(this,p);
if (result != PackageManager.PERMISSION_GRANTED) {
listPermissionsNeeded.add(p);
}
}
if (!listPermissionsNeeded.isEmpty()) {
ActivityCompat.requestPermissions(this, listPermissionsNeeded.toArray(new String[listPermissionsNeeded.size()]),10);
Log.d("permissionissue","no");
return false;
}
Log.d("permissionissue","yes");
return true;
}
@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
switch (requestCode) {
case 101:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
Toast.makeText(this, "Permission granted now you can read the storage", Toast.LENGTH_LONG).show();
checkPermission();
} else {
Toast.makeText(this, "Oops you just denied the permission", Toast.LENGTH_LONG).show();
try {
Log.d("deniedOnes",permissions[0] + " Denied!!!");
} catch (Exception e) {
e.printStackTrace();
}
}
break;
}
}