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如果我理解正確的話，在此我的代碼onLocationChanged方法應該會自動在每個1米叫，或0.4秒，因爲我已經設置locationManager.requestLocationUpdates(provider, 400, 1, this);onLocationChanged（）將不會自動調用
但沒有任何反應！當我按下按鈕時，onLocationChanged被調用。沒有自動調用，既不是每1秒也不是0.4秒。任何人都可以幫忙嗎？
public class MainActivity extends AppCompatActivity implements LocationListener {
LocationManager locationManager;
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
String provider;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
provider = locationManager.getBestProvider(new Criteria(),false);
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
Location location = locationManager.getLastKnownLocation(provider);
if (location != null) {
Log.i("Location Info", "Location achieved!");
Toast.makeText(getApplicationContext(),"Location achieved!",Toast.LENGTH_SHORT).show();
} else {
Log.i("Location Info", "No location :(");
Toast.makeText(getApplicationContext(),"No location :(",Toast.LENGTH_SHORT).show();
}
}
public boolean checkLocationPermission() {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission. ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
// Should we show an explanation?
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission. ACCESS_FINE_LOCATION)) {
// Show an explanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
new AlertDialog.Builder(this)
.setTitle("Title")
.setMessage("Text")
.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
//Prompt the user once explanation has been shown
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission. ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
}
})
.create()
.show();
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission. ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
}
return false;
} else {
return true;
}
}
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted, yay! Do the
// location-related task you need to do.
if (ContextCompat.checkSelfPermission(this,
Manifest.permission. ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
//Request location updates:
locationManager.requestLocationUpdates(provider, 400, 1, this);
}
} else {
// permission denied, boo! Disable the
// functionality that depends on this permission.
}
return;
}
}
}
@Override
protected void onResume() {
super.onResume();
checkLocationPermission();
}
@Override
protected void onPause() {
super.onPause();
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
locationManager.removeUpdates(this);
}
@Override
public void onLocationChanged(Location location) {
Double lat = location.getLatitude();
Double lng = location.getLongitude();
Log.i("Location info: Lat", lat.toString());
Log.i("Location info: Lng", lng.toString());
Toast.makeText(getApplicationContext(),"Location info: Lat"+lat.toString(),Toast.LENGTH_SHORT).show();
Toast.makeText(getApplicationContext(),"Location info: Lng"+lng.toString(),Toast.LENGTH_SHORT).show();
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
public void getLocation(View view) {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
Location location = locationManager.getLastKnownLocation(provider);
onLocationChanged(location);
}
}
如果您的應用程序已具有ACCESS_FINE_LOCATION權限，'locationManager.requestLocationUpdates（...）'將永遠不會被調用。 – Titus