Android动态刷新listview中的数据?

Question

项目里面的布局是这样的：一个Viewpager，Viewpager里面有三个Fragment，在第二个Fragment里面有一个ListView，使用了BaseAdapter来显示item。当时因为图方便，把获取数据源mData的方法直接写在了adapter的构造方法里面，数据源通过syncHttpClient向后台请求参数获取。

单击提示有错误：

CODE

package com.example.fiz.myapplication;

/**

• Created by Fiz on 16/3/21.

• 和服务器进行通信
  */

import android.annotation.SuppressLint;
import android.app.LauncherActivity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.ArrayAdapter;
import android.app.Activity;

import android.widget.SimpleAdapter;

import com.example.fiz.myapplogin.DjangoRestClient;
import com.loopj.android.http.JsonHttpResponseHandler;

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

import java.util.ArrayList;
import java.util.HashMap;

import cz.msebera.android.httpclient.Header;

@SuppressLint("ValidFragment")
public class Home extends Fragment {

private String textString;
private static final String Tag = "MainActivity";

private ArrayList<HashMap<String, Object>> arrayList = new ArrayList<HashMap<String, Object>>();

public Home(String textString) {
    this.textString = textString;
}

public static Home newInstance(String textString) {
    Home mFragment = new Home(textString);
    return mFragment;
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.home_page, container, false);
    final ListView listView = (ListView) view.findViewById(R.id.listView);
    try {
        getPublicTimeline();
    } catch (JSONException e) {
        e.printStackTrace();
    }
    final SimpleAdapter adapter = new SimpleAdapter(getActivity(), getData(), R.layout.home_page_text,
            new String[]{"news_title", "news_from", "news_judge","news_time"}, new int[]{R.id.news_title, R.id.news_from, R.id.news_judge,R.id.news_time});
    listView.setAdapter(adapter);

// adapter.notifyDataSetChanged();///

    /**
     *事件监听
     */
    listView.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            adapter.notifyDataSetChanged();
            if ( ! arrayList.get(position).equals(null)){
                Log.d(Tag, "THIS IS A JOKKE AA  UN FUNC  M ");

            }else {
                Log.d(Tag, "THIS IS A error are you undenstard AA  UN FUNC  M ");

            }

        }
    });

    return view;
}
/**

• 获取服务端数据
  */

1. void getPublicTimeline() throws JSONException {

      DjangoRestClient.get("/demo/test/?format=json",
              null, new JsonHttpResponseHandler() {
                  @Override
                  public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
                      // If the response is JSONObject instead of expected JSONArray
                      System.out.println(response);
                      try {
                          JSONArray array = response.getJSONArray("data");
   

                        System.out.print("状态码" + statusCode);

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

                }

                @Override
                public void onSuccess(int statusCode, Header[] headers, JSONArray timeline) {
                    // Pull out the first event on the public timeline
                    //这是我的后台适应编码

// System.out.println(timeline);

                    try {

// JSONObject firstEvent = (JSONObject) timeline.get(0);

                        JSONArray secondEvent = (JSONArray) timeline;

// String tweetText = firstEvent.getString("title");

                        // Do something with the response
                        for (int j = 0; j < secondEvent.length(); j++) {
                            JSONObject firstEvent = (JSONObject) timeline.get(j);
                            HashMap<String, Object> tempHashMap = new HashMap<String, Object>();
                            //新闻标题
                            String title = firstEvent.getString("title");
                            //新闻时间
                            String description = firstEvent.getString("description");
                            //新闻来源
                            String link = firstEvent.getString("link");
                            //新闻序号
                            String linkmd5id = firstEvent.getString("linkmd5id");
                            tempHashMap.put("news_title", title);
                            tempHashMap.put("news_from", link);
                            tempHashMap.put("news_judge", linkmd5id);
                            tempHashMap.put("news_time", description);
                            arrayList.add(tempHashMap);

                        }

                        System.out.println(arrayList);

// System.out.println(tweetText);

                    } catch (JSONException e) {
                        //do something
                    }

                }
            });

}

/**

• getData
  */

1. ArrayList<HashMap<String, Object>> getData() {

      return arrayList;
   

   }
   /**

   • 捕获单击事件
     */

}

LOG

                                                                               at android.widget.ListView.layoutChildren(ListView.java:1562)
                                                                               at android.widget.AbsListView$CheckForTap.run(AbsListView.java:3261)
                                                                               at android.os.Handler.handleCallback(Handler.java:739)
                                                                               at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                               at android.os.Looper.loop(Looper.java:135)
                                                                               at android.app.ActivityThread.main(ActivityThread.java:5221)
                                                                               at java.lang.reflect.Method.invoke(Native Method)
                                                                               at java.lang.reflect.Method.invoke(Method.java:372)
                                                                               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
                                                                               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

04-12 00:42:38.120 29022-29022/com.example.fiz.myapplication I/Process: Sending signal. PID: 29022 SIG: 9

Answer 1

经过一天的思考源码之后终于修改好了代码：当用AsyncHttpClient时，程序会自动新开一个线程，数据获取在一个线程，而adapter中的getCount又在另一个线程，两者的进度是无法把握的。
package com.example.fiz.myapplication;

/**

• Created by Fiz on 16/3/21.

• 和服务器进行通信
  */

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.os.Handler;
import android.widget.SimpleAdapter;
import com.example.fiz.myapplogin.DjangoRestClient;
import com.loopj.android.http.JsonHttpResponseHandler;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;

import cz.msebera.android.httpclient.Header;

@SuppressLint("ValidFragment")
public class Home2 extends Fragment {

private String textString;
private Handler mHandler;

private static final String Tag = "MainActivity";

private ArrayList<HashMap<String, Object>> arrayList = new ArrayList<HashMap<String, Object>>();

public Home2(String textString) {
    this.textString = textString;
}

public static Home2 newInstance(String textString) {
    Home2 mFragment = new Home2(textString);
    return mFragment;
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.home_page, container, false);
    final ListView listView = (ListView) view.findViewById(R.id.listView);
    DjangoRestClient.get("/demo/test/?format=json",
            null, new JsonHttpResponseHandler() {
                @Override
                public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
                    // If the response is JSONObject instead of expected JSONArray
                    System.out.println(response);
                    try {
                        JSONArray array = response.getJSONArray("data");

                        System.out.print("状态码" + statusCode);

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

                }

                @Override
                public void onSuccess(int statusCode, Header[] headers, JSONArray timeline) {
                    // Pull out the first event on the public timeline

                    try {
                        JSONArray secondEvent = (JSONArray) timeline;

                        for (int j = 0; j < secondEvent.length(); j++) {
                            JSONObject firstEvent = (JSONObject) timeline.get(j);
                            HashMap<String, Object> tempHashMap = new HashMap<String, Object>();
                            //新闻标题
                            String title = firstEvent.getString("title");
                            //新闻时间
                            String description = firstEvent.getString("description");
                            //新闻来源
                            String link = firstEvent.getString("link");
                            //新闻序号
                            String linkmd5id = firstEvent.getString("linkmd5id");
                            tempHashMap.put("news_title", title);
                            tempHashMap.put("news_from", link);
                            tempHashMap.put("news_judge", linkmd5id);
                            tempHashMap.put("news_time", description);
                            arrayList.add(tempHashMap);

                        }
                        final SimpleAdapter adapter = new SimpleAdapter(getActivity(), getData(), R.layout.home_page_text,
                                new String[]{"news_title", "news_from", "news_judge","news_time"},
                                new int[]{R.id.news_title, R.id.news_from, R.id.news_judge,R.id.news_time});

                        listView.setAdapter(adapter);

                        System.out.println(arrayList);

// System.out.println(tweetText);

                    } catch (JSONException e) {
                        //do something
                    }

                }
            });

    /**
     *事件监听
     */
    listView.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            if (!arrayList.get(position).equals(null)) {
                Log.d(Tag, "THIS IS A JOKKE AA  UN FUNC  M ");

            } else {
                Log.d(Tag, "THIS IS A error are you undenstard AA  UN FUNC  M ");

            }

        }
    });

    return view;
}

/**

• getData
  */

1. ArrayList<HashMap<String, Object>> getData() {

      return arrayList;
   

   }

}