我想分片访问我的当前位置。我写了这个程序。代码中没有错误，但仅显示Google地图；它不会显示我当前的位置和标记。
我对从清单和getApplicationContext访问权限感到困惑，因为我在那里使用getActivty()而不是this，因为它给了我错误。
我的代码有什么问题？
void locationTracker() {
SupportMapFragment mapFragment = (SupportMapFragment) getChildFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
if ((ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) && (ActivityCompat.checkSelfPermission(getActivity(), 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;
}
if (locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, new LocationListener() {
@Override
public void onLocationChanged(Location location) {
double latitude = location.getLatitude();
double longitude = location.getLongitude();
LatLng latLng= new LatLng(latitude,longitude);
Geocoder geocoder=new Geocoder(getActivity().getApplicationContext());
try {
List<Address> addressList = geocoder.getFromLocation(latitude,longitude,1);
String str = addressList.get(0).getLocality()+",";
str+= addressList.get(0).getCountryName();
mMap.addMarker(new MarkerOptions().position(latLng).title(str));
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
});
} else if (locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, new LocationListener() {
@Override
public void onLocationChanged(Location location) {
double latitude = location.getLatitude();
double longitude = location.getLongitude();
LatLng latLng= new LatLng(latitude,longitude);
Geocoder geocoder=new Geocoder(getActivity().getApplicationContext());
try {
List<Address> addressList = geocoder.getFromLocation(latitude,longitude,1);
String str = addressList.get(0).getLocality()+",";
str+= addressList.get(0).getCountryName();
mMap.addMarker(new MarkerOptions().position(latLng).title(str));
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
});
}
}
答案 0 :(得分：1)
1-如果您的android> 23，请确保在运行时询问位置许可
2-GPS无法在室内工作。
使用此代码在运行时询问位置权限
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
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(R.string.title_location_permission)
.setMessage(R.string.text_location_permission)
.setPositiveButton(R.string.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;
}
}
}
Then call the checkLocationPermission() method in onCreate():
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//.........
checkLocationPermission();
}
然后您可以完全按照问题中的方式使用onResume（）和onPause（）。
这是一个精简版，更简洁：
@Override
protected void onResume() {
super.onResume();
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
locationManager.requestLocationUpdates(provider, 400, 1, this);
}
}
@Override
protected void onPause() {
super.onPause();
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
locationManager.removeUpdates(this);
}
}
别忘了将其添加到清单
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />