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。