【发布时间】：2018-12-14 18:06:40
【问题描述】：
我需要在地图上显示我的“Npc”标记，但 onMapReady() 中的 npcList 是空的。如何将我的 Npc 从 getNPC() npcList 正确放入 onMapReady() npcList 中，然后在地图上显示标记
我的 onMapReady()：
public void onMapReady(GoogleMap googleMap) {
mGoogleMap = googleMap;
mGoogleMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
//zoom map camera
// Get LocationManager object
LocationManager locationManager = (LocationManager) getContext().getSystemService(Context.LOCATION_SERVICE);
// Create a criteria object to retrieve provider
Criteria criteria = new Criteria();
// Get the name of the best provider
String provider = (locationManager).getBestProvider(criteria, true);
Location myLocation = (locationManager).getLastKnownLocation(provider);
// myLastLoc = myLocation;
if (myLocation != null) {
//latitude of location
double myLatitude = myLocation.getLatitude();
//longitude og location
double myLongitude = myLocation.getLongitude();
LatLng latLon = new LatLng(myLatitude, myLongitude);
mGoogleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLon, 17));
}
mGoogleMap.setMyLocationEnabled(true);//koumpi gia location
buildGoogleApiClient(); // mallon mpilia
// locationManager.requestLocationUpdates(provider,1000,1f,com.google.android.gms.location.LocationListener);
npcList = new ArrayList<Npc>();
getNPC();
for(Npc mynpc:npcList) {
if (!npcList.isEmpty()) {
LatLng loc = new LatLng(mynpc.getNpclat(), mynpc.getNpclng());
String name = mynpc.getNpcname();
mGoogleMap.addMarker(new MarkerOptions()
.position(loc)
.title(name));
} else {
Toast.makeText(getActivity().getApplicationContext(), "npcList is empty", Toast.LENGTH_LONG).show();
}
}
}
我的 getNPC()：
private void getNPC() {
StringRequest stringRequest = new StringRequest(Request.Method.POST, Constants.URL_NPC_GET,
new com.android.volley.Response.Listener<String>() {
@Override
public void onResponse(String response) {
try {
JSONObject obj = new JSONObject(response);
Log.i("GAME_TAG", "response caught");
boolean error = obj.getBoolean("error");
if (!error) {
Log.i("GAME_TAG", "response showing return no error");
//converting the string to json array object
JSONArray array = obj.getJSONArray("results");
Log.i("GAME_TAG", "response has " + array.length() + " npcs");
//traversing through all the object
for (int i = 0; i < array.length(); i++) {
//getting npc object from json array
JSONObject npc = array.getJSONObject(i);
//adding the npc to npc list
npcList.add(new Npc(
npc.getInt("npcid"),
npc.getInt("userid"),
npc.getString("npcname"),
npc.getString("npcwelcome"),
(float) npc.getLong("npclat"),
(float) npc.getLong("npclng")
));
Log.i("GAME_TAG", "now arraylist has " + npcList.size() + " npcs");
Npc mynpc = npcList.get(i);
LatLng loc = new LatLng(mynpc.getNpclat(), mynpc.getNpclng());
String name = mynpc.getNpcname();
mGoogleMap.addMarker(new MarkerOptions()
.position(loc)
.title(name));
Log.i("GAME_TAG", "npc name "+ name+" " +loc);
}
Log.i("GAME_TAG", "if this sentence showing and still no marker, lets try adding only one marker");
LatLng loc = new LatLng(npcList.get(0).getNpclat(), npcList.get(0).getNpclng());
String name = npcList.get(0).getNpcname();
mGoogleMap.addMarker(new MarkerOptions()
.position(loc)
.title(name));
Log.i("GAME_TAG", "if this sentence showing and with one marker, something wrong with the loop");
} else {
Log.i("GAME_TAG", "response showing return with error");
}
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new com.android.volley.Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getActivity().getApplicationContext(), error.getMessage(), Toast.LENGTH_LONG).show();
}
});
RequestHandler.getInstance(getActivity()).addToRequestQueue(stringRequest);
}
我的 Npc 班级：
package com.example.game1;
public class Npc {
private int npcid;
private int userid;
private String npcname;
private String npcwelcome;
private float npclat;
private float npclng;
public Npc(int npcid,int userid,String npcname,String npcwelcome,float npclat,float npclng){
this.npcid = npcid;
this.userid = userid;
this.npcname = npcname;
this.npcwelcome = npcwelcome;
this.npclat = npclat;
this.npclng = npclng;
}
public int getNpcid() {
return npcid;
}
public int getUserid() {
return userid;
}
public String getNpcname() {
return npcname;
}
public String getNpcwelcome() {
return npcwelcome;
}
public float getNpclat() {
return npclat;
}
public float getNpclng() {
return npclng;
}
}
我正在从 db 中检索正确的值，如下图所示
请帮我卡住
【问题讨论】：
标签： android google-maps android-volley android-json