Android Launcher研究(三)-----------列出所安装的应用，点击进入相应的应用!

大家好，我今天给大家简单讲一下Launcher里如何列出所有安装的应用的，我们点击Launcher的抽屉(SlidingDrawer)就会 出现所有安装的应用列表(当然Widget,Launcher本身除外).并且点击应用图标进入 相关应用。我这里就先简单的用一个GridView来显示应用。

老样子我还会写一个简单的Demo让大家理解。大家跟着我的步骤来。

第一步：新建一个Android工程命名为:Launcher.

第二步:修改main.xml布局文件，代码如下(只有一个GridView这里):

 <?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/allapps"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
     />
 </LinearLayout>

<?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/allapps" android:layout_width="fill_parent" android:layout_height="wrap_content" /> </LinearLayout>

第三步:新建一个application_layout.xml布局文件，用来定义应用的图标和标题，代码如下:

 <?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/app_icon"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
     />
     <TextView
         android:id="@+id/app_title"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
     />
 </LinearLayout>

<?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/app_icon" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@+id/app_title" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </LinearLayout>

第四步：也就是核心了，修改Launcher.java代码如下:

 package  com.tutor.launcher;
 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  Launcher  extends  Activity  implements  OnItemClickListener{

     private  GridView mGridView;
     private  Context mContext;
     private  PackageManager mPackageManager;
     private  List<ResolveInfo> mAllApps;

     public   void  onCreate(Bundle savedInstanceState) {
         super .onCreate(savedInstanceState);
         setContentView(R.layout.main);

         setupViews();

     }

     public   void  setupViews(){
         mContext = Launcher.this ;
         mPackageManager = getPackageManager();
         mGridView = (GridView)findViewById(R.id.allapps);
         bindAllApps();

         mGridView.setAdapter(new  GridItemAdapter(mContext, mAllApps));
         mGridView.setNumColumns(4 );
         mGridView.setOnItemClickListener(this );
     }

     public   void  bindAllApps(){
         //这里是关键哦，我们平时写的应用总有一个activity申明成这两个属性
         //也就是应用的入口
         Intent mainIntent = new  Intent(Intent.ACTION_MAIN,  null );
         mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
         //符合上面条件的全部查出来,并且排序
         mAllApps = mPackageManager.queryIntentActivities(mainIntent, 0 );
         Collections.sort(mAllApps, new  ResolveInfo.DisplayNameComparator(mPackageManager));
     }



     //gridview点击事件，点击进入相关应用
     @Override
     public   void  onItemClick(AdapterView<?> parent, View view,  int  position,  long  id) {
         // TODO Auto-generated method stub
         ResolveInfo res = mAllApps.get(position);
         //该应用的包名和主Activity
         String pkg = res.activityInfo.packageName;
         String cls = res.activityInfo.name;

         ComponentName componet = new  ComponentName(pkg, cls);

         Intent i = new  Intent();
         i.setComponent(componet);
         startActivity(i);
     }

     //不明白BaseAdapter的用法 我高手进阶里有
     private   class  GridItemAdapter  extends  BaseAdapter{
         private  Context context;
         private  List<ResolveInfo> resInfo;

         //构造函数
         public  GridItemAdapter(Context c,List<ResolveInfo> res){
             context = c;
             resInfo = res;
         }
         @Override
         public   int  getCount() {
             // TODO Auto-generated method stub
             return  resInfo.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) {

             //不明白LayoutInflater的我android高手进阶里有
             convertView = LayoutInflater.from(context)
             .inflate(R.layout.application_layout, null );

             ImageView app_icon = (ImageView)convertView.findViewById(R.id.app_icon);
             TextView app_tilte = (TextView)convertView.findViewById(R.id.app_title);

             ResolveInfo res = resInfo.get(position);
             app_icon.setImageDrawable(res.loadIcon(mPackageManager));
             app_tilte.setText(res.loadLabel(mPackageManager).toString());
             return  convertView;
         }

     }
 }

package com.tutor.launcher; 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 Launcher extends Activity implements OnItemClickListener{ private GridView mGridView; private Context mContext; private PackageManager mPackageManager; private List<ResolveInfo> mAllApps; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); setupViews(); } public void setupViews(){ mContext = Launcher.this; mPackageManager = getPackageManager(); mGridView = (GridView)findViewById(R.id.allapps); bindAllApps(); mGridView.setAdapter(new GridItemAdapter(mContext, mAllApps)); mGridView.setNumColumns(4); mGridView.setOnItemClickListener(this); } public void bindAllApps(){ //这里是关键哦，我们平时写的应用总有一个activity申明成这两个属性 //也就是应用的入口 Intent mainIntent = new Intent(Intent.ACTION_MAIN, null); mainIntent.addCategory(Intent.CATEGORY_LAUNCHER); //符合上面条件的全部查出来,并且排序 mAllApps = mPackageManager.queryIntentActivities(mainIntent, 0); Collections.sort(mAllApps, new ResolveInfo.DisplayNameComparator(mPackageManager)); } //gridview点击事件，点击进入相关应用 @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { // TODO Auto-generated method stub ResolveInfo res = mAllApps.get(position); //该应用的包名和主Activity String pkg = res.activityInfo.packageName; String cls = res.activityInfo.name; ComponentName componet = new ComponentName(pkg, cls); Intent i = new Intent(); i.setComponent(componet); startActivity(i); } //不明白BaseAdapter的用法 我高手进阶里有 private class GridItemAdapter extends BaseAdapter{ private Context context; private List<ResolveInfo> resInfo; //构造函数 public GridItemAdapter(Context c,List<ResolveInfo> res){ context = c; resInfo = res; } @Override public int getCount() { // TODO Auto-generated method stub return resInfo.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) { //不明白LayoutInflater的我android高手进阶里有 convertView = LayoutInflater.from(context) .inflate(R.layout.application_layout, null); ImageView app_icon = (ImageView)convertView.findViewById(R.id.app_icon); TextView app_tilte = (TextView)convertView.findViewById(R.id.app_title); ResolveInfo res = resInfo.get(position); app_icon.setImageDrawable(res.loadIcon(mPackageManager)); app_tilte.setText(res.loadLabel(mPackageManager).toString()); return convertView; } } }

第五步:运行以上工程，得到的效果图如下:

图1.列出所有安装的应用.

图2.点击aQQ应用进入到相应的应用里。

OK,今天就写到这里，大家有什么不明白的地方可 以留言。thx~