我有一个在 2 周前可以正常工作的应用程序。今天我运行代码并遇到了一些问题。它似乎无法检测到我的 gps（位置选项）正在启动。位置关闭时，我会在启动时弹出一条消息并要求打开位置选项，打开后它会显示我当前的位置。但是，如果我退出应用程序并重新打开它，即使位置选项仍然打开，它也不会显示我的当前位置。
同样，它曾经工作过，我总是能够在启动时获得我当前的位置，但我不知道为什么它不再工作了，因为我没有改变任何东西。
Location location = locationManager.getLastKnownLocation(provider) 始终返回 null。
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Getting GoogleMap object from the fragment
googleMap = fm.getMap();
// Enabling MyLocation Layer of Google Map
googleMap.setMyLocationEnabled(true);
googleMap.setPadding(0, 0, 0, 90);
//loadSettings();
// Getting LocationManager object from System Service LOCATION_SERVICE
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
if (locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
//Toast.makeText(this, "GPS is Enabled in your devide", Toast.LENGTH_SHORT).show();
}else{
showGPSDisabledAlertToUser();
}
googleMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
@Override
public void onMapClick(LatLng point) {
changeLocation(point);
}
});
// Creating a criteria object to retrieve provider
Criteria criteria = new Criteria();
// Getting the name of the best provider
provider = locationManager.getBestProvider(criteria, true);
// Getting Current Location
Location location = locationManager.getLastKnownLocation(provider);
if(location!=null){
onLocationChanged(location);
}
locationManager.requestLocationUpdates(provider, 20000, 0, this);
private void showGPSDisabledAlertToUser(){
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
alertDialogBuilder.setMessage("GPS is disabled in your device. Would you like to enable it?")
.setCancelable(false)
.setPositiveButton("Goto Settings Page To Enable GPS",
new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int id){
Intent callGPSSettingIntent = new Intent(
android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(callGPSSettingIntent);
}
});
alertDialogBuilder.setNegativeButton("Cancel",
new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int id){
dialog.cancel();
}
});
AlertDialog alert = alertDialogBuilder.create();
alert.show();
}