sss我从json数组得到lat和lng但是当我尝试将它添加到我的集群时，我得到空对象引用
我的活动
public class TabFragment2 extends Fragment implements OnMapReadyCallback {
private static View rootView;
public ClusterManager<MyItem> mClusterManager;
private GetAsync getAsync ;
private boolean first = true;
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_Coordinates = "products";
private static final String TAG_PID = "pid";
private static final String TAG_X = "x_coordinate";
private static final String TAG_Y = "y_coordinate";
String type = "0";
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
Log.i("myMapFragment","onCreateView");
if (rootView != null) {
ViewGroup parent = (ViewGroup) rootView.getParent();
if (parent != null)
parent.removeView(rootView);
return rootView;
}
try {
rootView = inflater.inflate(R.layout.tab_fragment_2, container, false);
} catch (InflateException e) {
/* map is already there, just return view as it is */
}
SupportMapFragment mSupportMapFragment = (SupportMapFragment) this.getFragmentManager().findFragmentById(R.id.map);
if (mSupportMapFragment == null) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
mSupportMapFragment = SupportMapFragment.newInstance();
fragmentTransaction.replace(R.id.map, mSupportMapFragment).commit();
}
if (mSupportMapFragment != null) {
mSupportMapFragment.getMapAsync(this);
}
new GetAsync().execute(type);
return rootView;
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Log.i("myMapFragment","onActivityCreated");
if (first){
Log.i("if first","yes");
getAsync = new GetAsync ();
getAsync.execute();
first = false;
}
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
Log.i("myMapFragment","onViewCreated");
}
public void onDestroyView() {
super.onDestroyView();
Log.i("myMapFragment", "onDestroyView");
}
@Override
public void onMapReady(GoogleMap map) {
LatLng sydney = new LatLng(-33.867, 151.206);
if (ActivityCompat.checkSelfPermission(getContext(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(getContext(), 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;
}
map.setMyLocationEnabled(true);
Log.i("on Map Ready", "yes");
map.moveCamera(CameraUpdateFactory.newLatLngZoom(sydney, 13));
map.addMarker(new MarkerOptions()
.icon(BitmapDescriptorFactory.fromResource(R.drawable.blue_pin))
.anchor(0.0f, 1.0f) // Anchors the marker on the bottom left
.position(new LatLng(-33.867, 151.206)));
setUpCluster(map);
}
@Override
public void onPause() {
super.onPause();
Log.i("myMapFragment","onPause");
}
@Override
public void onStop() {
super.onStop();
Log.i("myMapFragment","onStop");
}
@Override
public void onResume() {
super.onResume();
//initilizeMap();
Log.i("myMapFragment","onResume");
}
private void setUpCluster(GoogleMap map){
ClusterManager<MyItem> mClusterManager;
// Initialize the manager with the context and the map.
// (Activity extends context, so we can pass 'this' in the constructor.)
mClusterManager = new ClusterManager<MyItem>(getActivity(),map);
// Setting the custom render
//mClusterManager.setRenderer(new MyClusterRenderer(getActivity(), googleMap, mClusterManager));
// Point the map's listeners at the listeners implemented by the cluster manager.
map.setOnCameraChangeListener(mClusterManager);
map.setOnMarkerClickListener(mClusterManager);
// Point the map's listeners at the listeners implemented by the cluster manager.
mClusterManager.setOnClusterItemClickListener(new ClusterManager.OnClusterItemClickListener<MyItem>() {
@Override
public boolean onClusterItemClick(MyItem offsetItem) {
return false;
}
});
}
private class GetAsync extends AsyncTask<String, String, JSONArray> {
JSONParser jsonParser = new JSONParser();
private ProgressDialog pDialog;
private static final String URL = "http://www.xxx.com.au/find/locations2.php";
private static final String TAG_SUCCESS = "success";
private static final String TAG_MESSAGE = "message";
//private Context context;
// public GetAsync(Context context) {
// this.context = context;
// }
@Override
protected void onPreExecute() {
pDialog = new ProgressDialog(getContext());
pDialog.setMessage("Attempting login...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected JSONArray doInBackground(String... args) {
try {
HashMap<String, String> params = new HashMap<>();
params.put("type", args[0]);
Log.d("request", "starting");
JSONObject json = jsonParser.makeHttpRequest(
URL, "GET", params);
if (json != null) {
Log.d("JSON result", json.toString());
return json.getJSONArray(TAG_Coordinates);
}
else {
Log.d("JSON", "null");
}
} catch (Exception e) {
Log.d("JSON", "ex");
}
return null;
}
//@Override
protected void onPostExecute(JSONArray products) {
String json_string;
if (pDialog != null && pDialog.isShowing()) {
pDialog.dismiss();
}
if (products != null) {
json_string = products.toString();
Log.d("JSON onpost", json_string);
for (int i = 0; i < products.length(); i++) {
Log.d("for", "yes");
JSONObject c = null;
try {
c = products.getJSONObject(i);
// Storing each json item in variable
int id = c.getInt(TAG_PID);
double lat = c.getDouble(TAG_X);
double lng = c.getDouble(TAG_Y);
Log.d("Lat", String.valueOf(lat));
Log.d("Lng", String.valueOf(lng));
MyItem offsetItem = new MyItem(lat, lng);
mClusterManager.addItem(offsetItem);
} catch (JSONException e) {
Toast.makeText(getActivity(), "Problem reading list of markers", Toast.LENGTH_SHORT).show();
}
}
}
}
}
}
My Item.java
public class MyItem implements ClusterItem {
private final LatLng mPosition;
public MyItem(double lat, double lng) {
mPosition = new LatLng(lat, lng);
}
@Override
public LatLng getPosition() {
return mPosition;
}
}
logcat的
03-18 03:59:24.621 19167-19167/com.joey.mapdemo D/JSON onpost:
[{"pid":"2","x_coordinate":"-33.713165","y_coordinate":"151.297577"},{"pid":"5","x_coordinate":"-33.676090","y_coordinate":"151.302689"},{"pid":"6","x_coordinate":"-33.830978","y_coordinate":"151.205521"},{"pid":"7","x_coordinate":"-28.857418","y_coordinate":"153.560822"}]
03-18 03:59:24.622 19167-19167/com.joey.mapdemo D/for: yes
03-18 03:59:24.625 19167-19167/com.joey.mapdemo D/Lat: -33.713165
03-18 03:59:24.625 19167-19167/com.joey.mapdemo D/Lng: 151.297577
03-18 03:59:24.686 19167-19167/com.joey.mapdemo D/AndroidRuntime: Shutting down VM
03-18 03:59:24.702 19167-19167/com.joey.mapdemo E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.joey.mapdemo, PID: 19167
java.lang.NullPointerException: Attempt to invoke virtual method 'void
com.google.maps.android.clustering.ClusterManager.addItem(com.google.maps.android.clustering.ClusterItem)'
on a null object reference
at com.joey.mapdemo.TabFragment2$GetAsync.onPostExecute(TabFragment2.java:267)
at com.joey.mapdemo.TabFragment2$GetAsync.onPostExecute(TabFragment2.java:185)