The error comes because of the location listener is null.I put the location listener in the JsonObjectRequest of volley library.
my code is
protected void onCreate(Bundle savedInstanceState) {
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);
mLocationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
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;
}
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 500, 1, mLocationListener);
}
/**
* 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;
mMap.setMyLocationEnabled(true);
// Add a marker in Sydney and move the camera
UiSettings uiSettings=mMap.getUiSettings();
uiSettings.setZoomControlsEnabled(true);
//mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
requestQueue= Volley.newRequestQueue(this);
JsonObjectRequest jsonObjectRequest=new JsonObjectRequest(Request.Method.GET, loginUrl, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray ja = response.getJSONArray("hi");
retid= new String[ja.length()];
retph= new String[ja.length()];
retname=new String[ja.length()];
retlat= new Double[ja.length()];
retlong= new Double[ja.length()];
for(int i=0;i<ja.length();i++){
JSONObject jsonObject=ja.getJSONObject(i);
if(!(jsonObject.getString("retailer_loc_lat").equals("0")&&jsonObject.getString("retailer_loc_long").equals("0"))) {
retid[i] = jsonObject.getString("retailer_id") + "";
retname[i] = jsonObject.getString("retailer_first_name") + " " + jsonObject.getString("retailer_last_name");
retlat[i] = Double.parseDouble(jsonObject.getString("retailer_loc_lat"));
retlong[i] = Double.parseDouble(jsonObject.getString("retailer_loc_long"));
retph[i] = "Phone:" + jsonObject.getString("retailer_ph_no");
}
}
mLocationListener = new LocationListener() {
@Override
public void onLocationChanged(final Location location) {
for(int j=0;j<retid.length;j++){
if(almostEqual(retlat[j],location.getLatitude(),.5)&&almostEqual(retlong[j],location.getLatitude(),.5)){
mMap.addMarker(new MarkerOptions().position(new LatLng(retlat[j], retlong[j])).title(retname[j]).snippet(retph[j]).icon(BitmapDescriptorFactory.fromResource(R.drawable.map_pin_96)));
}
}
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
};
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});requestQueue.add(jsonObjectRequest);
}
my log cat
Caused by: java.lang.IllegalArgumentException: invalid listener: null
at android.location.LocationManager.checkListener(LocationManager.java:1606)
at android.location.LocationManager.requestLocationUpdates(LocationManager.java:426)
The main reason is that the location manager cant get the location listener in
the JsonObjectRequest. Please help.
mapFragment.getMapAsync(this); is an aysnchronous non-blocking call.
Hence
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 500, 1, mLocationListener);
gets executed before you get onMapReady() callback.
Now since mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 500, 1, mLocationListener); gets executed before onMapReady() , mLocationListener is null since you haven't initialized it before. And that's why you get Exception.