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):

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<?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>

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<?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:

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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。