显示所有应用程序列表,点击进入

package com.example.likeqq;

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

import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.View;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class MainActivity extends Activity {
	ListView lv;
	SimpleAdapter adapter;
	ArrayList<HashMap<String, Object>> items = new ArrayList<HashMap<String, Object>>();
	PackageManager pm;
 
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		lv = (ListView) findViewById(R.id.listview);
		final PackageManager pm = getPackageManager();
		// 得到PackageManager对象
		List<PackageInfo> packs = pm
				.getInstalledPackages(PackageManager.GET_UNINSTALLED_PACKAGES);
		// 得到系统 安装的所有程序包的PackageInfo对象
 
		for (PackageInfo pi : packs) {
			HashMap<String, Object> map = new HashMap<String, Object>();
			map.put("icon", pi.applicationInfo.loadIcon(pm));
			// 图标
			map.put("appName", pi.applicationInfo.loadLabel(pm));
			// 应用名
			map.put("packageName", pi.packageName);
			// 包名
			items.add(map);
			// 循环读取存到HashMap,再增加到ArrayList.一个HashMap就是一项
		}
 
		adapter = new SimpleAdapter(this, items, R.layout.piitem, new String[] {
				"icon", "appName", "packageName" }, new int[] { R.id.icon,
				R.id.appName, R.id.packageName });
		// 参数:Context,ArrayList(item的集合),item的layout,包含ArrayList中Hashmap的key的数组,key所对应的值相对应的控件id
		lv.setAdapter(adapter);
		lv.setOnItemClickListener(new OnItemClickListener() {
 
			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				// TODO Auto-generated method stub
				String packageName = (String) items.get(position).get(
						"packageName");
				//取到点击的包名
				Intent i = pm.getLaunchIntentForPackage(packageName);
				//如果该程序不可启动（像系统自带的包，有很多是没有入口的）会返回NULL
				if (i != null)
					startActivity(i);
			}
 
		});
 
	}

}

布局文件就不添加了，都是listView的基础布局