下面是我的MapsActivity.java， 我试图getCurrentLocation并将标记放在那里。 当我运行应用程序时，我无法在地图上看到标记。什么地方出了错？ 谢谢你的帮助。
import android.Manifest;
import android.content.pm.PackageManager;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import com.bustracker.usc.myapplication.R;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import java.io.IOException;
import java.util.List;
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
private LocationManager manager;
private LocationListener locationListener;
@Override
protected void onCreate(Bundle savedInstanceState) {
Log.d("INSIDE ONCREATE", "TRUE");
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
//get the location service
manager = (LocationManager) getSystemService(LOCATION_SERVICE);
//request the location update thru location manager
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;
}
Log.d("BFORE ISPROVIDERENABLED", "TRUE");
if (manager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
manager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, new LocationListener() {
@Override
public void onLocationChanged(Location location) {
//get the latitude and longitude from the location
double latitude = location.getLatitude();
double longitude = location.getLongitude();
Log.d("LATLNG", latitude+" " +longitude);
//get the location name from latitude and longitude
Geocoder geocoder = new Geocoder(getApplicationContext());
try {
List<Address> addresses =
geocoder.getFromLocation(latitude, longitude, 1);
String result = addresses.get(0).getSubLocality() + ":";
result += addresses.get(0).getLocality() + ":";
result += addresses.get(0).getCountryCode();
LatLng latLng = new LatLng(latitude, longitude);
mMap.addMarker(new MarkerOptions().position(latLng).title(result));
mMap.setMaxZoomPreference(20);
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(manager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
manager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, new LocationListener() {
@Override
public void onLocationChanged(Location location) {
//get the latitude and longitude from the location
double latitude = location.getLatitude();
double longitude = location.getLongitude();
//get the location name from latitude and longitude
Geocoder geocoder = new Geocoder(getApplicationContext());
try {
List<Address> addresses =
geocoder.getFromLocation(latitude, longitude, 1);
String result = addresses.get(0).getSubLocality() + ":";
result += addresses.get(0).getLocality() + ":";
result += addresses.get(0).getCountryCode();
LatLng latLng = new LatLng(latitude, longitude);
mMap.addMarker(new MarkerOptions().position(latLng).title(result));
mMap.setMaxZoomPreference(20);
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) {
}
});
}
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
// Add a marker in Sydney and move the camera
// LatLng sydney = new LatLng(-34, 151);
// mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
// mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}
@Override
protected void onPause() {
super.onPause();
manager.removeUpdates(locationListener);
Log.i("onPause...","paused");
}
}
上面是我的MapsActivity.java， 我试图getCurrentLocation并将标记放在那里。 当我运行应用程序时，我无法在地图上看到标记。什么地方出了错？ 谢谢你的帮助。
答案 0 :(得分：0)
尝试在onMapReady方法内创建地图的标记和所有内容，如果它不起作用，请尝试查看您是否正确获取了地理位置
希望它对你有所帮助，Pd：对不起我的英语
答案 1 :(得分：0)
确保您获得有效latLng
OR
如果要添加自定义图标以设置标记，请将其添加为：
map.addMarker(new MarkerOptions().position(latLng).title(result)).icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED)));