i've got a problem. I'm trying to retrieve data from my MySQL server with an AsyncTask.
public class HomeFragment extends Fragment {
// RecyclerView
RecyclerView recyclerView;
RecyclerView.Adapter rvAdapter;
RecyclerView.LayoutManager rvLayoutManger;
List<NewsData> news_list;
@Nullable
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_home, null);
// RecyclerView Setup
recyclerView = (RecyclerView) view.findViewById(R.id.recycler_view1);
rvLayoutManger = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(rvLayoutManger);
rvAdapter = new HomeRecyclerAdapter(getActivity(), news_list);
recyclerView.setAdapter(rvAdapter);
news_list = new ArrayList<>();
load_data_from_server(0);
return view;
}
private void load_data_from_server(int i) {
AsyncTask<Integer, Void, Void> task = new AsyncTask<Integer, Void, Void>() {
@Override
protected Void doInBackground(Integer... params) {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder().url("here is my URL").build();
try {
Response response = client.newCall(request).execute();
JSONArray array = new JSONArray(request.body().toString());
for (int i = 0; i < array.length(); i++) {
JSONObject object = array.getJSONObject(i);
NewsData data = new NewsData(object.getInt("id"), object.getString("title"), object.getString("describtion"));
news_list.add(data);
}
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
System.out.print("End of content");
}
return null;
}
@Override
protected void onPostExecute(Void aVoid) {
rvAdapter.notifyDataSetChanged();
}
};
task.execute(id);
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
}
This is my Class that should retrieve the data and i wanna list it in an RecyclerView thats why i got this Adapter.
public class HomeRecyclerAdapter extends RecyclerView.Adapter<HomeRecyclerAdapter.ViewHolder> {
private Context context;
private List<NewsData> news_list;
public HomeRecyclerAdapter(Context context, List<NewsData> news_list) {
this.context = context;
this.news_list = news_list;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_cardviewhome, parent, false);
return new ViewHolder(itemView);
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.title.setText(news_list.get(position).getTitle());
}
@Override
public int getItemCount() {
return 0;
}
public class ViewHolder extends RecyclerView.ViewHolder{
public TextView title;
public ViewHolder(View itemView){
super(itemView);
title = (TextView) itemView.findViewById(R.id.title_cView);
}
}
}
But after I run it i got this error
E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
Process: com.example.andreundjulia.dbg_ahlhorn, PID: 25407
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:309)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference
at com.example.andreundjulia.dbg_ahlhorn.Fragments.HomeFragment$1.doInBackground(HomeFragment.java:73)
at com.example.andreundjulia.dbg_ahlhorn.Fragments.HomeFragment$1.doInBackground(HomeFragment.java:65)
at android.os.AsyncTask$2.call(AsyncTask.java:295)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@9bd1046 time:652009764 V/FA: Screen exposed for less than 1000 ms. Event not sent. time: 248 V/FA: Activity paused, time: 1189877240 D/ViewRootImpl: #3 mView = null V/FA: Inactivity, disconnecting from the service Application terminated.
So I would like to know if someone of you guys could help me with this by the way here is my Getter/Setter Class.
public class NewsData {
private int id;
private String title, describtion;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public NewsData(int id, String title, String describtion){
this.id = id;
this.title = title;
this.describtion = describtion;
}
public String getTitle(){
return title;
}
public void setTitle(String title){
this.title = title;
}
public String getDescribtion(){
return describtion;
}
public void setDescribtion(String describtion) {
this.describtion = describtion;
}
I hope someone could help me i stuck here for very long time and cant get me out alone :/
Thank you!
