我正在尝试从gps获取2个位置之间的区别,每当我点击按钮转到我的MapsActivity时,我都会遇到此错误
Attempt to invoke virtual method 'com.google.android.gms.maps.model.Marker com.google.android.gms.maps.GoogleMap.addMarker(com.google.android.gms.maps.model.MarkerOptions)' on a null object reference
当我评论检查距离差异的代码它工作正常,我不明白标记选项和DistanceTo之间的连接 这是我的代码(请记住,一切正常,只是DistanceTo不起作用)
locationListener = 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 {
if(location != null)
// this gives address list from the maps, not important and commented
{
List<Address> addresses =
geocoder.getFromLocation(latitude, longitude, 1);
// Marker options where the issue occurs
//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("Marker Title"));
mMap.setMaxZoomPreference(20);
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
}
} catch (IOException e) {
e.printStackTrace();
}
//Where it checks for the locations and the distance between them
if(LocationA == null) {
LocationA = location;
}
LocationB = location;
LocationA = LocationB;
DiffernceInDistance = LocationA.distanceTo(LocationB);
}
我制作地图的代码
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
if(ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
else {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
答案 0 :(得分:0)
问题在于我在寻找位置并同时应用标记,因此标记无法加载到该位置,为了解决它我评论过,它不会再崩溃但是它没有解决我的主要问题(距离没有工作,但这不是我发布这篇文章的原因,因此我不会再要求帮助了谢谢)
mMap.addMarker(new MarkerOptions().position(latLng).title("Marker Title"));