Question

Json数据未显示在列表视图中。请检查我的代码代码中缺少的内容。我在logcat中获取数据但未在列表视图中显示。请检查谢谢。

com.example.nkrajput01.myapplication;

import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.text.method.ScrollingMovementMethod;
import android.util.Log;
import android.util.StringBuilderPrinter;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;

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

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;

public class MainActivity extends AppCompatActivity {

ListView listView;
ProgressDialog progressDialog;
    ArrayList<HashMap<String, String>> contactList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        contactList = new ArrayList<>();

        listView = (ListView) findViewById(R.id.list);




      /*  FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });*/



          new GetContacts().execute();


    }

    private class GetContacts extends AsyncTask<Void, Void, Void>{

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            progressDialog = new ProgressDialog(MainActivity.this);
            progressDialog.setMessage("downloading content...");
            progressDialog.setCancelable(false);
            progressDialog.show();
        }

        @Override
        protected Void doInBackground(Void... params) {
            String url = "http://api.androidhive.info/contacts/";
            try{
                URL url_ = new URL(url);
                HttpURLConnection httpURLConnection = (HttpURLConnection)url_.openConnection();

                httpURLConnection.setRequestMethod("GET");

                InputStream in = new BufferedInputStream(httpURLConnection.getInputStream());

                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(in));

                StringBuilder sb = new StringBuilder();
                int line=0;

                while ((line=bufferedReader.read())!= -1)
                {
                  sb.append((char) line);

                }


              Log.d("Data", sb.toString());


                String jsonString = sb.toString();

                JSONObject jsonObject = new JSONObject(jsonString);

                JSONArray jsonArray = jsonObject.getJSONArray("contacts");


                for (int i = 0; i <jsonArray.length() ; i++) {

                    JSONObject c = jsonArray.getJSONObject(i);

                    String id = c.getString("id");
                    String name = c.getString("name");
                    String email = c.getString("email");
                    String address = c.getString("address");
                    String gender = c.getString("gender");

                    JSONObject aa = c.getJSONObject("phone");
                    String mobile = aa.getString("mobile");
                    String home = aa.getString("home");
                    String office =aa.getString("office");

                    HashMap<String, String> contact = new HashMap<>();

                    contact.put(id, "id");
                    contact.put(name, "name");
                    contact.put(email, "email");
                    contact.put(mobile, "mobile");

                   contactList.add(contact);

                }


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


            return null;
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            if (progressDialog.isShowing())

                progressDialog.dismiss();


                 Log.d("ContactList", contactList.toString());

            ListAdapter adapter = new SimpleAdapter(
                    MainActivity.this, contactList,
                    R.layout.list_item, new String[]{"name", "email",
                    "mobile"}, new int[]{R.id.name,
                    R.id.email, R.id.mobile});
                listView.setAdapter(adapter);



        }
    }




    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

Answer 1

您似乎混淆了联系人HashMap的键和值：

contact.put(id, "id");
contact.put(name, "name");
contact.put(email, "email");
contact.put(mobile, "mobile");

第一个参数是键，第二个是值，所以代码应该是：

contact.put("id", id);
contact.put("name", name);
contact.put("email", email);
contact.put("mobile", mobile);

Json解析的数据没有显示在listView

1 个答案: