Android得到系统已安装应用程序包列表方法 自定义ListView显示 PackageManager的使用

得到系统安装的程序包,可以通过PackageManager对象getInstalledPackages方法,该方法直接返回一个包含程序包信息PackageInfo的List。今天学习PackageManager的同时,顺便记一下ListView使用自定义适配器以及自定义视图的方法,前面写得不够详细。先看效果图:

每一项分成三部分,左边是应用图标,右边分上下两部分,上面是应用名,下面是包名。顺便说一下,ListView的自定义布局,定义的是一项的布局,然后根据项的数量叠加。
下面是这个布局的xml代码 piitem.xml:


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="horizontal" android:layout_width="fill_parent"
	android:layout_height="fill_parent">
	<ImageView android:id="@+id/icon" android:layout_width="48dip"
		android:layout_height="48dip" />
	<LinearLayout android:orientation="vertical"
		android:layout_width="fill_parent" android:layout_height="wrap_content">
		<TextView android:id="@+id/appName" android:layout_width="fill_parent" android:layout_height="wrap_content"/>
		<TextView android:id="@+id/packageName" android:layout_width="fill_parent" android:layout_height="wrap_content"/>
	</LinearLayout>
</LinearLayout>

main.xml的布局就不贴了吧,就一个ListView,id为lv
写个自定义的适配器:


package com.pocketdigi;
import java.util.List;
import java.util.Map;

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.SimpleAdapter;
import android.widget.TextView;

public class Adapter extends SimpleAdapter {
	private int[] mTo;
    private String[] mFrom;
    private ViewBinder mViewBinder;
    private List> mData;
    private int mResource;
    private LayoutInflater mInflater;
	public Adapter(Context context,List> data, int resource, String[] from,int[] to) {
		super(context, data, resource, from, to);
		mData = data;
        mResource = resource;
        mFrom = from;
        mTo = to;
        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
	}
 
    public View getView(int position, View convertView, ViewGroup parent) {
        return createViewFromResource(position, convertView, parent, mResource);
    }
    private View createViewFromResource(int position, View convertView,
            ViewGroup parent, int resource) {
        View v;
        if (convertView == null) {
            v = mInflater.inflate(resource, parent, false);
 
            final int[] to = mTo;
            final int count = to.length;
            final View[] holder = new View[count];
 
            for (int i = 0; i < count; i++) {
                holder[i] = v.findViewById(to[i]);
            }
            v.setTag(holder);
        } else {
            v = convertView;
        }
        bindView(position, v);
        return v;
    }
 
    private void bindView(int position, View view) {
        final Map dataSet = mData.get(position);
        if (dataSet == null) {
            return;
        }
 
        final ViewBinder binder = mViewBinder;
        final View[] holder = (View[]) view.getTag();
        final String[] from = mFrom;
        final int[] to = mTo;
        final int count = to.length;
 
        for (int i = 0; i < count; i++) {
            final View v = holder[i];
            if (v != null) {
                final Object data = dataSet.get(from[i]);
                String text = data == null ? "" : data.toString();
                if (text == null) {
                    text = "";
                }
 
                boolean bound = false;
                if (binder != null) {
                    bound = binder.setViewValue(v, data, text);
                }
 
                if (!bound) {
                	//自定义适配器,关键在这里,根据传过来的控件类型以及值的数据类型,执行相应的方法
                	//可以根据自己需要自行添加if语句。另CheckBox等继承自TextView的控件也会被识别成TextView, 这就需要判断值的类型了
                  if (v instanceof TextView) {
                	  //如果是TextView控件
                        setViewText((TextView) v, text);
                        //调用SimpleAdapter自带的方法,设置文本
                    } else if (v instanceof ImageView) {//如果是ImageView控件
                        setViewImage((ImageView) v, (Drawable) data); 
                        //调用下面自己写的方法,设置图片
                    } else {
                        throw new IllegalStateException(v.getClass().getName() + " is not a " +
                                " view that can be bounds by this SimpleAdapter");
                    }
                }
            }
        }
    }
 
    public void setViewImage(ImageView v, Drawable value) {
    	v.setImageDrawable(value);

    }
 
};

关键部分已注释,如果用到其他控件,只要修改注释的地方增加判断就可以了。
下面是主程序代码 Main.java:


package com.pocketdigi;

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

import android.app.Activity;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.widget.ListView;

public class Main extends Activity {
	/** Called when the activity is first created. */
	ListView lv;
	Adapter adapter;
	ArrayList> items=new ArrayList>();

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		lv = (ListView) findViewById(R.id.lv);
		PackageManager  pm= getPackageManager();
		//得到PackageManager对象
		List packs = pm.getInstalledPackages(0);
		//得到系统 安装的所有程序包的PackageInfo对象
		
		for (PackageInfo pi : packs) {
			HashMap map = new HashMap();
			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 Adapter(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);

	}
}

最后方便初学者,打个包:
[download id="21"]

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