Android Launcher研究(三)-----------列出所安裝的應用，點擊進入相應的應用!

你們好，我今天給你們簡單講一下Launcher裏如何列出全部安裝的應用的，咱們點擊Launcher的抽屜(SlidingDrawer)就會 出現全部安裝的應用列表(固然Widget,Launcher自己除外).而且點擊應用圖標進入 相關應用。我這裏就先簡單的用一個GridView來顯示應用。

老樣子我還會寫一個簡單的Demo讓你們理解。你們跟着個人步驟來。

第一步：新建一個Android工程命名爲:Launcher.

第二步:修改main.xml佈局文件，代碼以下(只有一個GridView這裏):

<?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:新建一個application_layout.xml佈局文件，用來定義應用的圖標和標題，代碼以下:

<?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代碼以下:

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(){
        //這裏是關鍵哦，咱們平時寫的應用總有一個activity申明成這兩個屬性
        //也就是應用的入口
        Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
        mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        //符合上面條件的所有查出來,而且排序
        mAllApps = mPackageManager.queryIntentActivities(mainIntent, 0);
        Collections.sort(mAllApps, new ResolveInfo.DisplayNameComparator(mPackageManager));
    }



    //gridview點擊事件，點擊進入相關應用
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        // TODO Auto-generated method stub
        ResolveInfo res = mAllApps.get(position);
        //該應用的包名和主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 我高手進階裏有
    private class GridItemAdapter extends BaseAdapter{
        private Context context;
        private List<ResolveInfo> resInfo;

        //構造函數
        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高手進階裏有
            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(){ //這裏是關鍵哦，咱們平時寫的應用總有一個activity申明成這兩個屬性 //也就是應用的入口 Intent mainIntent = new Intent(Intent.ACTION_MAIN, null); mainIntent.addCategory(Intent.CATEGORY_LAUNCHER); //符合上面條件的所有查出來,而且排序 mAllApps = mPackageManager.queryIntentActivities(mainIntent, 0); Collections.sort(mAllApps, new ResolveInfo.DisplayNameComparator(mPackageManager)); } //gridview點擊事件，點擊進入相關應用 @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { // TODO Auto-generated method stub ResolveInfo res = mAllApps.get(position); //該應用的包名和主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 我高手進階裏有 private class GridItemAdapter extends BaseAdapter{ private Context context; private List<ResolveInfo> resInfo; //構造函數 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高手進階裏有 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:運行以上工程，獲得的效果圖以下:

圖1.列出全部安裝的應用.

圖2.點擊aQQ應用進入到相應的應用裏。