【ListViewJson】【MainActivity功能性分析，不讨论具体工具类的实现】【android解析json数据（包含对图片数据的异步缓存处理），并将其加载到listview中】

package com.demo.app.ui;

import java.util.List;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;

import com.demo.app.AppContext;
import com.demo.app.AppException;
import com.demo.app.R;
import com.demo.app.adapter.MainListViewAdapter;
import com.demo.app.bean.News;
import com.demo.app.bean.NewsList;
import com.demo.app.common.UIHelper;
import com.demo.app.widget.MyListView;

public class MainActivity extends Activity {
    private MyListView listview;
    private List<News> newsList;
    private AppContext appContext;// 全局Context
    private MainListViewAdapter listViewAdapter;
    private ProgressDialog selectorDialog;
    private Button bt_news, bt_forum, bt_cartype, bt_favour, bt_more;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        appContext = (AppContext) getApplication();
        // 网络连接判断
        if (!appContext.isNetworkConnected())
            UIHelper.ToastMessage(this, R.string.network_not_connected);
        init();
        initData();
    }

    private void init() {
        bt_news = (Button) findViewById(R.id.bt_news);
        bt_forum = (Button) findViewById(R.id.bt_forum);
        bt_cartype = (Button) findViewById(R.id.bt_cartype);
        bt_favour = (Button) findViewById(R.id.bt_favour);
        bt_more = (Button) findViewById(R.id.bt_more);
        bt_news.setSelected(true);
        bt_news.setOnClickListener(onClick(bt_news));
        bt_forum.setOnClickListener(onClick(bt_forum));
        bt_cartype.setOnClickListener(onClick(bt_cartype));
        bt_favour.setOnClickListener(onClick(bt_favour));
        bt_more.setOnClickListener(onClick(bt_more));
        listview = (MyListView) findViewById(R.id.news_listview);
        selectorDialog = ProgressDialog.show(this, null, "正在加载，请稍候...", true,
                false);

    }

    private View.OnClickListener onClick(final Button btn) {
        return new View.OnClickListener() {
            public void onClick(View v) {

                bt_news.setSelected(false);
                bt_forum.setSelected(false);
                bt_cartype.setSelected(false);
                bt_favour.setSelected(false);
                bt_more.setSelected(false);
                if (btn == bt_news) {
                    bt_news.setSelected(true);
                } else if (btn == bt_forum) {
                    bt_forum.setSelected(true);
                } else if (btn == bt_cartype) {
                    bt_cartype.setSelected(true);
                } else if (btn == bt_favour) {
                    bt_favour.setSelected(true);
                } else if (btn == bt_more) {
                    bt_more.setSelected(true);
                }
            }
        };
    }

    Handler mHandler = new Handler() {
        public void handleMessage(Message msg) {
            selectorDialog.cancel();
            if (msg.what == 1) {
                newsList = (List<News>) msg.obj;
                listViewAdapter = new MainListViewAdapter(MainActivity.this,
                        newsList);
                listview.setAdapter(listViewAdapter);
            } else if (msg.what == -1) {
                UIHelper.ToastMessage(MainActivity.this, "没有数据");
            } else if (msg.what == -2) {
                UIHelper.ToastMessage(MainActivity.this,
                        R.string.xml_parser_failed);
            }
        }
    };

    private void initData() {

        selectorDialog.show();
        new Thread() {
            public void run() {
                Message msg = new Message();
                boolean isRefresh = false;
                try {
                    NewsList list = appContext.getNewsList();
                    if (list.getNewsCount() > 0) {
                        msg.what = 1;
                        msg.obj = list.getNewslist();
                        appContext.saveObject(list, "newslist_");
                    } else {
                        msg.what = -1;
                    }
                } catch (AppException e) {
                    e.printStackTrace();
                    msg.what = -2;
                    msg.obj = e;
                }
                mHandler.sendMessage(msg);
            }
        }.start();
    }
}

 appContext = (AppContext) getApplication();

 if (!appContext.isNetworkConnected())
            UIHelper.ToastMessage(this, R.string.network_not_connected);

init();
initData();

Handler mHandler = new Handler() {
        public void handleMessage(Message msg) {
            selectorDialog.cancel();
            if (msg.what == 1) {
                newsList = (List<News>) msg.obj;
                listViewAdapter = new MainListViewAdapter(MainActivity.this,
                        newsList);
                listview.setAdapter(listViewAdapter);
            } else if (msg.what == -1) {
                UIHelper.ToastMessage(MainActivity.this, "没有数据");
            } else if (msg.what == -2) {
                UIHelper.ToastMessage(MainActivity.this,
                        R.string.xml_parser_failed);
            }
        }
    };

    private void initData() {

        selectorDialog.show();
        new Thread() {
            public void run() {
                Message msg = new Message();
                boolean isRefresh = false;
                try {
                    NewsList list = appContext.getNewsList();
                    if (list.getNewsCount() > 0) {
                        msg.what = 1;
                        msg.obj = list.getNewslist();
                        appContext.saveObject(list, "newslist_");
                    } else {
                        msg.what = -1;
                    }
                } catch (AppException e) {
                    e.printStackTrace();
                    msg.what = -2;
                    msg.obj = e;
                }
                mHandler.sendMessage(msg);
            }
        }.start();
    }