我正在使用以下类，它们可以正常使用静态数据。
这是我的JSON回复
[{"place_name":"Udon House"},{"place_name":"Casa Biance"},{"place_name":"Pizza hut"},{"place_name":"Pearl Continental "},{"place_name":"Lahore Meuseum"},{"place_name":"Shalimar Gardens"}]
这是我的POJO课程
public class places {
//Variable in json
public String place_name;
//Getters and setters
public String getPlace_name() {
return place_name;
}
public void setPlace_name(String name) {
this.place_name = name;
}
}
这是我的CustomAdapter类
public class placesAdapter extends
RecyclerView.Adapter<placesAdapter.ViewHolder> {
places places;
private Context context;
private List<places> places_list;
placesAPI p;
public placesAdapter(List<places> places)
{
this. places_list = places;
}
@Override
public placesAdapter.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.card_item, viewGroup, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(placesAdapter.ViewHolder viewHolder, int i) {
places_list.get(i);
viewHolder.place_name.setText(places_list.get(i).getPlace_name());
}
@Override
public int getItemCount() {
if (places_list != null) {
return places_list.size();
}
return 0;
}
public class ViewHolder extends RecyclerView.ViewHolder{
private TextView place_name;
public ViewHolder(View view) {
super(view);
place_name = (TextView)view.findViewById(R.id.tv_blah);
}
}
}
这是我的片段类
public class BlankFragment extends Fragment {
List<places> placesData;
//placesAdapter adapter;
RecyclerView rv;
public BlankFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView = inflater.inflate(R.layout.fragment_blank, container, false);
rv = (RecyclerView) rootView.findViewById(R.id.rv_recycler_view);
rv.setHasFixedSize(true);
//RecyclerView.Adapter<String> adapter = new Adapter<>(getActivity(), R.layout.custom_tab);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
rv.setLayoutManager(llm);
final placesAdapter rvAdapter = new placesAdapter(getActivity(), placesData);
rv.setAdapter(rvAdapter);
RequestQueue requestQueue = Volley.newRequestQueue(getActivity());
String url = "http://192.168.10.5/tourist/placeTest.php";
JsonArrayRequest req = new JsonArrayRequest(url,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
try {
List<places> placesArray = new ArrayList<places>();
JSONArray jsonArray = response.getJSONArray(response.toString());
for (int i = 0; i < response.length(); i++) {
JSONObject placeObject = jsonArray.getJSONObject(i);
places p = new places();
p.place_name = placeObject.getString("place_name");
placesArray.add(p);
}
rvAdapter.notifyDataSetChanged();
}
catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
}
});
requestQueue.add(req);
// Adding request to request queue
return rootView;
}
}
android moniter给了我这个：
07-25 12:59:00.048 830-830/? E/NetworkScheduler.SR: Invalid package name : Perhaps you didn't include a PendingIntent in the extras?
07-25 12:59:00.923 513-572/? E/KeyguardUpdateMonitor: Object tried to add another callback
java.lang.Exception: Called by
at com.android.internal.policy.impl.keyguard.KeyguardUpdateMonitor.registerCallback(KeyguardUpdateMonitor.java:1107)
at com.android.internal.policy.impl.keyguard.KeyguardSelectorView.onResume(KeyguardSelectorView.java:331)
at com.android.internal.policy.impl.keyguard.KeyguardHostView.onScreenTurnedOn(KeyguardHostView.java:1118)
at com.android.internal.policy.impl.keyguard.KeyguardViewManager.onScreenTurnedOn(KeyguardViewManager.java:404)
at com.android.internal.policy.impl.keyguard.KeyguardViewMediator.handleNotifyScreenOn(KeyguardViewMediator.java:1767)
at com.android.internal.policy.impl.keyguard.KeyguardViewMediator.access$2300(KeyguardViewMediator.java:106)
at com.android.internal.policy.impl.keyguard.KeyguardViewMediator$4.handleMessage(KeyguardViewMediator.java:1413)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:194)
at android.os.HandlerThread.run(HandlerThread.java:60)
07-25 12:59:00.935 135-9746/? E/AudioMTKHardware: setParameters() still have param.size() = 1, remain param = "screen_state=on"
07-25 12:59:05.455 22623-22623/? E/dalvikvm: Could not find class 'android.app.AppOpsManager', referenced from method com.google.android.gms.common.GooglePlayServicesUtil.a
07-25 12:59:06.122 20191-21273/? E/dalvikvm: Could not find class 'android.telephony.CellInfoWcdma', referenced from method nqp.a
07-25 12:59:06.196 22623-22623/? E/dalvikvm: Could not find class 'com.facebook.common.jobscheduler.compat.JobServiceCompat', referenced from method com.facebook.common.jobscheduler.compat.ServiceInfoParser.<init>
07-25 12:59:06.846 22603-22603/? E/dalvikvm: Could not find class 'android.content.pm.LauncherApps', referenced from method com.google.android.apps.gsa.search.shared.multiuser.l.connect
07-25 12:59:06.993 20191-21273/? E/dalvikvm: Could not find class 'android.telephony.CellInfoWcdma', referenced from method nqp.c
07-25 12:59:07.369 20191-21273/? E/dalvikvm: Could not find class 'android.telephony.CellInfoWcdma', referenced from method nqq.a
07-25 12:59:10.201 22674-22674/com.nuku.mc.populate_recyclerview E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.NullPointerException
at com.nuku.mc.populate_recyclerview.BlankFragment$1.onResponse(BlankFragment.java:79)
at com.nuku.mc.populate_recyclerview.BlankFragment$1.onResponse(BlankFragment.java:64)
at com.android.volley.toolbox.JsonRequest.deliverResponse(JsonRequest.java:65)
at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:99)
at android.os.Handler.handleCallback(Handler.java:800)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5371)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)
07-25 12:59:10.348 513-574/? E/AppErrorDialog: Failed to get ILowStorageHandle instance
07-25 12:59:11.632 513-811/? E/CellLocation: create GsmCellLocation
07-25 12:59:11.651 513-571/? E/CellLocation: create GsmCellLocation
07-25 12:59:11.663 843-1303/? E/CellLocation: create GsmCellLocation
07-25 12:59:11.704 513-571/? E/CellLocation: create GsmCellLocation
答案 0 :(得分：0)
尝试使用此方法并检查您的日志中是否正确显示JsonArray：
public void getJsonArray()
{
String url = "http://192.168.10.5/tourist/placeTest.php";
JsonArrayRequest req = new JsonArrayRequest(url,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
List<String> placesArray= new ArrayList<String>();
JSONArray jsonArray = response.getJSONArray(response.toString());
for (int i=0; i<cast.length(); i++) {
JSONObject placeObject = jsonArray.getJSONObject(i);
String name = placeObject.getString("place_name");
placesArray.add(name);
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
pDialog.hide();
}
});
// Adding request to request queue
requestQueue.add(req);
}
答案 1 :(得分：0)
您必须事先初始化placesData列表，然后使用它来添加json数组中的对象。请注意标有// IMPORTANT!!!：
public class BlankFragment extends Fragment {
List<places> placesData = new ArrayList<>(); // IMPORTANT!!!
//...
JsonArrayRequest req = new JsonArrayRequest(url,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
try {
for (int i = 0; i < response.length(); i++) {
JSONObject placeObject = jsonArray.getJSONObject(i);
places p = new places();
p.place_name = placeObject.getString("place_name");
placesData.add(p); // IMPORTANT!!!
}
rvAdapter.notifyDataSetChanged();
}
catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
}
});
requestQueue.add(req);
return rootView;
}
}
此外，您不需要placesArray方法
onResponse