java - Json 不显示 url 数据

Question

I am trying to fetch JSON Data from Google spreadsheet but it is not showing up I don't know why.I think My JSON response is not matching with the match class do have a look and help me out

这是我的 AsyncResult 接口(interface)

包 com.textview.android.jsonsuccessful; 导入 org.json.JSONObject； 接口(interface)异步结果{ void onResult(JSONObject 对象); }

这是我用来获取 URL 数据的类

package com.textview.android.jsonsuccessful;
import android.os.AsyncTask;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;


public class DownloadWebpageTask extends AsyncTask<String, Void, String> {
AsyncResult callback;

public DownloadWebpageTask(AsyncResult callback) {
    this.callback = callback;
}

  @Override
  protected String doInBackground(String... urls) {

     // params comes from the execute() call: params[0] is the url.
     try {
          return downloadUrl(urls[0]);
      } catch (IOException e) {
          return "Unable to download the requested page.";
    }
  }

  // onPostExecute displays the results of the AsyncTask.
  @Override
  protected void onPostExecute(String result) {
     // remove the unnecessary parts from the response and construct a JSON
    int start = result.indexOf("{", result.indexOf("{") + 1);
    int end = result.lastIndexOf("}");
    String jsonResponse = result.substring(start, end);
    try {
        JSONObject team = new JSONObject(jsonResponse);
        callback.onResult(team);
    } catch (JSONException e) {
        e.printStackTrace();
    }
}

  private String downloadUrl(String urlString) throws IOException {
     InputStream is = null;

     try {
         URL url = new URL(urlString);
          HttpURLConnection conn = (HttpURLConnection) url.openConnection();
           conn.setReadTimeout(10000 /* milliseconds */);
         conn.setConnectTimeout(15000 /* milliseconds */);
          conn.setRequestMethod("GET");
           conn.setDoInput(true);
          // Starts the query
             conn.connect();
         int responseCode = conn.getResponseCode();
          is = conn.getInputStream();   

          String contentAsString = convertStreamToString(is);
           return contentAsString;
       } finally {
          if (is != null) {
            is.close();
           }
      }
   }

       private String convertStreamToString(InputStream is) {
        BufferedReader reader = new BufferedReader(new    
      InputStreamReader(is));
       StringBuilder sb = new StringBuilder();

       String line = null;
        try {
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
         }
        } catch (IOException e) {
        e.printStackTrace();
        } finally {
        try {
            is.close();
          } catch (IOException e) {
             e.printStackTrace();
        }
        }
       return sb.toString();
    } 
 }

这是我的主要 Activity

package com.textview.android.jsonsuccessful;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

  private static final String DEBUG_TAG = "HttpExample";
  ArrayList<Team> teams = new ArrayList<Team>();
  ListView listview;
  Button btnDownload;

  @Override
   protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    listview = (ListView) findViewById(R.id.listview);
    btnDownload = (Button) findViewById(R.id.btnDownload);
    ConnectivityManager connMgr = (ConnectivityManager)                                 
    getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
    if (networkInfo != null && networkInfo.isConnected()) {
        btnDownload.setEnabled(true);
    } else {
        btnDownload.setEnabled(false);
    }
    } 

    public void buttonClickHandler(View view) {
    new DownloadWebpageTask(new AsyncResult() {
        @Override
        public void onResult(JSONObject object) {
            processJson(object);
        }
    }).execute([google]"https://spreadsheets.google.com/tq?  
  key=1424bS7kU8nJbHdu4QdoAFdIdWDSnmEnj2NqfMb6rPTU");

    }

     private void processJson(JSONObject object) {

    try {
        JSONArray rows = object.getJSONArray("rows");

        for (int r = 0; r < rows.length(); ++r) {
            JSONObject row = rows.getJSONObject(r);
            JSONArray columns = row.getJSONArray("c");

            int Code = columns.getJSONObject(0).getInt("v");
            String Name = columns.getJSONObject(1).getString("v");
            String Father = columns.getJSONObject(3).getString("v");
            String Sessional = columns.getJSONObject(4).getString("v");
            String Comments = columns.getJSONObject(5).getString("v");

            Team team = new Team(Code, Name, Father, Sessional,Comments);
            teams.add(team);
        }

        final TeamsAdapter adapter = new TeamsAdapter(this, R.layout.team,      teams);
        listview.setAdapter(adapter);

    } catch (JSONException e) {
        e.printStackTrace();
    }
}

这是我的匹配类

package com.textview.android.jsonsuccessful;
public class Team {
private int Code;
private String Name;
private String Father;
private String Sessional;
private String Comments;

public Team(int Code, String Name, String Father, String Sessional, String      Comments) {
    this.setCode(Code);
    this.setName(Name);
    this.setFatherName(Father);
    this.setSessionalMarks(Sessional);
    this.setComments(Comments);

}

public int getCode() {
    return Code;
}

public void setCode(int Code) {
    this.Code = Code;
}

public String getName() {
    return Name;
}

public void setName(String Name) {
    this.Name = Name;
}

public String getFatherName() {
    return Father;
}

public void setFatherName(String FatherName) {
    this.Father = FatherName;
}

public String getSessionalMarks() {
    return Sessional;
}

public void setSessionalMarks(String SessionalMarks) {
    this.Sessional = SessionalMarks;
}

public String getComments() {
    return Comments;
}

public void setComments(String Comments) {
    this.Comments = Comments;
}
       }

这是我的适配器

package com.textview.android.jsonsuccessful;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import java.util.ArrayList;


public class TeamsAdapter extends ArrayAdapter<Team> {

Context context;
private ArrayList<Team> teams;

public TeamsAdapter(Context context, int textViewResourceId, ArrayList<Team>   items) {
    super(context, textViewResourceId, items);
    this.context = context;
    this.teams = items;
}

@Override
public View getView(int Code, View convertView, ViewGroup parent) {
    View v = convertView;
    if (v == null) {
        LayoutInflater vi = (LayoutInflater)    context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        v = vi.inflate(R.layout.team, null);
    }
    Team o = teams.get(Code);
    if (o != null) {
        TextView Cod = (TextView) v.findViewById(R.id.Code);
        TextView Name = (TextView) v.findViewById(R.id.Name);
        TextView Father = (TextView) v.findViewById(R.id.Father);
        TextView Comments = (TextView) v.findViewById(R.id.Comments);
        TextView Sessional = (TextView) v.findViewById(R.id.Sessional);


        Cod.setText(String.valueOf(o.getCode()));
        Name.setText(String.valueOf(o.getName()));
        Father.setText(String.valueOf(o.getFatherName()));
        Sessional.setText(String.valueOf(o.getSessionalMarks()));
        Comments.setText(String.valueOf(o.getComments()));

    }
    return v;
}

这是我的主要 xml

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.textview.android.jsonsuccessful.MainActivity">

<ListView
    android:id="@+id/listview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_below="@+id/btnDownload" />

<Button
    android:id="@+id/btnDownload"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:enabled="false"
    android:onClick="buttonClickHandler"
    android:text="download table"
    />


</RelativeLayout>`

这是我的 team.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView
    android:id="@+id/Code"
    android:text="201"
    android:layout_width="0dp"
    android:layout_weight=".35"
    android:layout_height="wrap_content" />

<TextView
    android:id="@+id/Name"
    android:text="ankit"
    android:layout_width="0dp"
    android:layout_weight=".50"
    android:layout_height="wrap_content" />

<TextView
    android:id="@+id/Father"
    android:text="Ramesh"
    android:layout_width="0dp"
    android:layout_weight=".70"
    android:layout_height="wrap_content" />

<TextView
    android:id="@+id/Sessional"
    android:text="maths 15 ,english 20, physics 30,computer 7,Gk 12"
    android:layout_width="0dp"
    android:layout_weight="1.5"
    android:layout_height="wrap_content" />

<TextView
    android:id="@+id/Comments"
    android:text="should put more efforts"
    android:layout_width="0dp"
    android:layout_weight="1"
    android:layout_height="wrap_content" />


</LinearLayout>

Answer 1

在解析 JSON 数据时，您正在解析一个额外的对象“Comments”，它在您的 JSON 文件中不存在。 因此，您的数组“teams”未填充数据。

public class MainActivity extends AppCompatActivity {

    private static final String DEBUG_TAG = "HttpExample";
    ArrayList<Team> teams = new ArrayList<Team>();
    ListView listview;
    Button btnDownload;
    TeamsAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        listview = (ListView) findViewById(R.id.listview);
        btnDownload = (Button) findViewById(R.id.btnDownload);
        ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
        if (networkInfo != null && networkInfo.isConnected()) {
            btnDownload.setEnabled(true);
        } else {
            btnDownload.setEnabled(false);
        }
    }

    public void buttonClickHandler(View view) {
        new DownloadWebpageTask(new AsyncResult() {
            @Override
            public void onResult(JSONObject object) {
                processJson(object);
            }
        }).execute("https://spreadsheets.google.com/tq?key=1424bS7kU8nJbHdu4QdoAFdIdWDSnmEnj2NqfMb6rPTU");

    }

    private void processJson(final JSONObject object) {
        try {
            JSONArray rows = object.getJSONArray("rows");
            for (int r = 0; r < rows.length(); ++r) {
                JSONObject row = rows.getJSONObject(r);
                JSONArray columns = row.getJSONArray("c");
                int Code = columns.getJSONObject(0).getInt("v");
                String Name = columns.getJSONObject(1).getString("v");
                String Father = columns.getJSONObject(3).getString("v");
                String Sessional = columns.getJSONObject(4).getString("v");
                //String Comments = columns.getJSONObject(5).getString("v");
                String Comments = "Error";
                Team team = new Team(Code, Name, Father, Sessional, Comments);
                teams.add(team);
                }
            adapter = new TeamsAdapter(MainActivity.this, R.layout.team, teams);
            listview.setAdapter(adapter);
         } catch (JSONException e) {
             e.printStackTrace();
         }
     }
}