Hello Guys I received a a big problem in my project. I make the OkHttp request i receive response from server all is perfect. the problem is why i can't display data, i made a model item in xml and listview(this is the required view) and when i acces the page is blank.
Can anyone help me with this issue?
code for page is the following:
package com.example.socceraplication;
import static android.content.ContentValues.TAG;
import androidx.appcompat.app.AppCompatActivity;
import androidx.annotation.NonNull;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SearchView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import com.google.gson.Gson;
import java.util.ArrayList;
import java.util.HashMap;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.ExecutionException;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.ResponseBody;
import java.util.ArrayList;
public class TeamInfo extends AppCompatActivity {
private ListView lv;
ArrayList<HashMap<String, String>> resultList;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_team_info);
resultList = new ArrayList<>();
lv = (ListView) findViewById(R.id.list);
new GetContacts().execute();
}
private class GetContacts extends AsyncTask<Void, Void, Void>{
@Override
protected void onPreExecute() {
super.onPreExecute();
Toast.makeText(TeamInfo.this,"Json Data is downloading",Toast.LENGTH_LONG).show();
}
@Override
protected Void doInBackground(Void... arg0) {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("https://heisenbug-premier-league-live-scores-v1.p.rapidapi.com/api/premierleague/team?name=Liverpool")
.get()
.addHeader("X-RapidAPI-Key", "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")
.addHeader("X-RapidAPI-Host", "heisenbug-premier-league-live-scores-v1.p.rapidapi.com")
.build();
client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(@NonNull Call call, @NonNull IOException e) {
call.cancel();
}
@Override
public void onResponse(@NonNull Call call, @NonNull Response response) throws IOException {
String jsonStr=response.body().string();
Log.e(TAG, "Response from url: " jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
JSONArray records = jsonObj.getJSONArray("records");
// looping through All items
for (int i = 0; i < records.length(); i ) {
JSONObject c = records.getJSONObject(i);
String league = c.getString("league");
String season = c.getString("season");
String name = c.getString("name");
String officialName = c.getString("officialName");
String address = c.getString("address");
String telephone = c.getString("telephone");
String fax = c.getString("fax");
String website = c.getString("website");
String founded = c.getString("founded");
String teamSize = c.getString("teamSize");
String averageAge = c.getString("averageAge");
String foreigners = c.getString("foreigners");
String nationaTeamPlayers = c.getString("nationaTeamPlayers");
String teamValue = c.getString("teamValue");
String venue = c.getString("venue");
String venueCapacity = c.getString("venueCapacity");
HashMap<String, String> result = new HashMap<>();
// adding each child node to HashMap key => value
result.put("league",league);
result.put("season",season);
result.put("name",name);
result.put("officialName",officialName);
result.put("address",address);
result.put("telephone",telephone);
result.put("fax",fax);
result.put("website",website);
result.put("founded",founded);
result.put("teamSize",teamSize);
result.put("averageAge",averageAge);
result.put("foreigners",foreigners);
result.put("nationaTeamPlayers",nationaTeamPlayers);
result.put("teamValue",teamValue);
result.put("venue",venue);
result.put("venueCapacity",venueCapacity);
resultList.add(result);
}
} catch (final JSONException e) {
Log.e(TAG, "Json parsing error: " e.getMessage());
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"Json parsing error: " e.getMessage(), Toast.LENGTH_LONG).show();
}
});
}
}else {
Log.e(TAG, "Couldn't get json from server.");
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"Couldn't get json from server. Check LogCat for possible errors!",
Toast.LENGTH_LONG).show();
}
});
}
}
});
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
ListAdapter adapter = new SimpleAdapter(TeamInfo.this, resultList,
R.layout.list_item_team, new String[]{ "league","season","name","officialName","address","telephone","fax","website","founded","teamSize","averageAge","foreigners","nationaTeamPlayers","teamValue","venue","venueCapacity"},
new int[]{R.id.league, R.id.season,R.id.name,R.id.officialName,R.id.address,R.id.telephone,R.id.fax,R.id.website,R.id.founded,R.id.teamSize,R.id.averageAge,R.id.foreigners,R.id.nationaTeamPlayers,R.id.teamValue,R.id.venue,R.id.venueCapacity});
lv.setAdapter(adapter);
}
}
}
CodePudding user response：
The enqueue call is asynchronous, which means it queues up work to be run in the background at some point in the future, and when it is complete then it runs the callback you supply (onResponse). This means in your case the order of calls is
- Start doInBackground
- Add your Http call to the queue
- Return from doInBackground
- Run onPostExecute
- Post empty list to the adapter
- ... some time later ...
- Run the onResponse callback when it gets data
To fix this, you can remove the async task entirely and just queue the work from the main thread, since it already handles actually doing the request in the background.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_team_info);
resultList = new ArrayList<>();
lv = (ListView) findViewById(R.id.list);
startRequest();
}
private void startRequest() {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
//...
.build();
client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(@NonNull Call call, @NonNull IOException e) {
call.cancel();
}
@Override
public void onResponse(@NonNull Call call, @NonNull Response response) {
showResult(response);
}
});
}
private void showResult(Response response) {
// show the result here - no need to runOnUiThread
// set the adapter, put text in views, etc from in here
}
If you really want to make the call from your own AsyncTask in the background, you should use the synchronous API, not the asynchronous API. This means calling execute instead of enqueue, like this:
// this MUST run on a background thread or it will block the UI thread
Response response = client.newCall(request).execute();