android 列出所有的应用

     在android中实现一个像桌面那样把所有应用都列举出来。用GridView来实现显示。

    主要代码如下：

    先修改main.xml文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<GridView
	android:id="@+id/gridView"
	android:layout_width="fill_parent"
	android:layout_height="wrap_content"
/>
</LinearLayout>

然后创建一个xml文件来显示你想在GridView中显示的格式，我这边是用一个图标加一个文件来显示的。

application.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >

<ImageView
	android:id="@+id/icon"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
/>
<TextView
	android:id="@+id/title"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
/>    
</LinearLayout>

接下来是主要代码的实现了。

package com.mzz;

import java.util.Collections;
import java.util.List;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;

public class ListApplications extends Activity implements OnItemClickListener{
	
	private GridView mGridView = null ;
	
	private PackageManager mPackageManager = null ;
	
	private List<ResolveInfo> mAllApps =  null ;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        showView();
    }

    public void showView() {
    	mPackageManager = getPackageManager();
    	mGridView = (GridView)findViewById(R.id.gridView);
    	getAllApps();
    	
    	mGridView.setAdapter(new MyAdapter(ListApplications.this , mAllApps));
    	mGridView.setNumColumns(3);//每行显示3个
    	mGridView.setOnItemClickListener(this);
    }
    
    public void getAllApps() {
    	//设置一个Intent的action和category为需要显示
    	Intent intent = new Intent(Intent.ACTION_MAIN , null);
    	intent.addCategory(Intent.CATEGORY_LAUNCHER);
    	
    	//如何条件的查出来
    	mAllApps = mPackageManager.queryIntentActivities(intent, 0);
    	//排序
    	Collections.sort(mAllApps, new ResolveInfo.DisplayNameComparator(mPackageManager));
    }
    
    //当点击gridview中的图标时，进入相应的应用
	@Override
	public void onItemClick(AdapterView<?> parent, View view, int position,
			long id) {
		// TODO Auto-generated method stub
		ResolveInfo res = mAllApps.get(position);
		//得到该应用的包名和activity
		String pkg = res.activityInfo.packageName ;
		String cls = res.activityInfo.name ;
		
		ComponentName mComponentName = new ComponentName(pkg, cls);
		Intent intent = new Intent();
		intent.setComponent(mComponentName);
		startActivity(intent);
	}
	
	//Adapter
	class MyAdapter extends BaseAdapter {

		private Context mContext ;
		private List<ResolveInfo> mAllApps ;
		
		MyAdapter(Context context , List<ResolveInfo> allApps) {
			mContext = context ;
			mAllApps = allApps ;
		}
		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			return mAllApps.size();
		}

		@Override
		public Object getItem(int position) {
			// TODO Auto-generated method stub
			return null;
		}

		@Override
		public long getItemId(int position) {
			// TODO Auto-generated method stub
			return 0;
		}

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			// TODO Auto-generated method stub
			convertView = LayoutInflater.from(mContext).inflate(R.layout.applications, null);
			ImageView icon = (ImageView)convertView.findViewById(R.id.icon);
			TextView title = (TextView)convertView.findViewById(R.id.title);
			ResolveInfo res = mAllApps.get(position);
			icon.setImageDrawable(res.loadIcon(mPackageManager));
			title.setText(res.loadLabel(mPackageManager));
			return convertView;
		}
		
	}
}

到这里代码的全部编写完成了。

效果如下图所见:

虽然和本身的显示相比，我的这个有点丑。没有处理图标的大小，不过功能上实现了。当你点击相应的图标的时候，会进入相应的应用的主Activity。

呵呵。。。