java Google在检索纬度和经度时映射NullPointerException
我试图创建一个谷歌地图活动,获取用户的当前位置,并在用户的当前位置上放置一个pin。我用静态的纬度和经度值尝试了代码,地图正常工作。当我试图以编程方式获取LatLong值时,系统在第127行抛出了一个NullPointerException,其中包含代码double longitude = location.getLongitude();
我做错了什么,如何纠正?提前感谢您的帮助
活动代码
@Override
public void onMapReady(GoogleMap googleMap) {
try {
if (ContextCompat.checkSelfPermission(getActivity().getApplicationContext(), 安卓.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED ) {
ActivityCompat.requestPermissions(getActivity(), new String[]{安卓.Manifest.permission.ACCESS_FINE_LOCATION}, 101);
}
} catch (Exception e){
e.printStackTrace();
}
LocationManager lm = (LocationManager)getActivity().getSystemService(Context.LOCATION_SERVICE);
Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
double longitude = location.getLongitude();
double latitude = location.getLatitude();
gmap = googleMap;
gmap.setMinZoomPreference(12);
gmap.setIndoorEnabled(true);
UiSettings uiSettings = gmap.getUiSettings();
uiSettings.setIndoorLevelPickerEnabled(true);
uiSettings.setMyLocationButtonEnabled(true);
uiSettings.setMapToolbarEnabled(true);
uiSettings.setCompassEnabled(true);
uiSettings.setZoomControlsEnabled(true);
LatLng ny = new LatLng(latitude, longitude);
gmap.moveCamera(CameraUpdateFactory.newLatLng(ny));
}
Logcat
Process: ke.co.mytech.mytech, PID: 8425
java.lang.NullPointerException: Attempt to invoke virtual method 'double 安卓.location.Location.getLongitude()' on a null object reference
at ke.co.mytech.mytech.HomeFragment.onMapReady(HomeFragment.java:127)
at com.google.安卓.gms.maps.zzac.zza(Unknown Source)
at com.google.安卓.gms.maps.internal.zzaq.dispatchTransaction(Unknown Source)
at com.google.安卓.gms.internal.maps.zzb.onTransact(Unknown Source)
at 安卓.os.Binder.transact(Binder.java:392)
at fg.b(:com.google.安卓.gms.dynamite_mapsdynamite@13280046@13.2.80 (040306-211705629):19)
at com.google.安卓.gms.maps.internal.bg.a(:com.google.安卓.gms.dynamite_mapsdynamite@13280046@13.2.80 (040306-211705629):5)
at com.google.maps.api.安卓.lib6.impl.be.run(:com.google.安卓.gms.dynamite_mapsdynamite@13280046@13.2.80 (040306-211705629):5)
at 安卓.os.Handler.handleCallback(Handler.java:815)
at 安卓.os.Handler.dispatchMessage(Handler.java:104)
at 安卓.os.Looper.loop(Looper.java:207)
at 安卓.app.ActivityThread.main(ActivityThread.java:5728)
at java.lang.reflect.Method.invoke(Native Method)
at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:679)
# 1 楼答案
找到了我做错了什么的答案in this question
# 2 楼答案
一些可能有帮助的事情
第一,尝试使用FusedLocationProviderClient获取位置
其次,我在emulator上测试时遇到了这个问题,它总是引发与您提到的相同的异常。我修复它的方法是进入模拟器上的谷歌地图应用程序,让它通过点击圆圈目标按钮来确定我的位置。我不确定它为什么起作用(我想是因为它保存了我以前无法保存的位置)