引用：http://www.cnblogs.com/playing/archive/2011/04/13/2014705.html
第一步，把我们的应用程序作为home（即实现按下home键，启动自己的launcher.）
要把我们的应用程序作为home，只需要在AndroidManifest.xml中添加：
<category android:name="android.intent.category.HOME" />
<category android:name="android.intent.category.DEFAULT" />
AndroidManifest.xml
第二步，列出安装的应用程序
列出已经安装的应用程序是作为launcher比不可少的功能。下面我们就讲解怎样将应用程序列出来。程序运行后的样子如下：
1. 修改main.xml，在其中添加一个GridView用来显示应用程序列表。
main.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">
<GridView android:layout_width="match_parent"
android:id="@+id/apps_list"
android:numColumns="4"
android:layout_height="wrap_content">
</GridView>
</LinearLayout
2 . 通过PackageManager的api 查询已经安装的apk
privatevoid loadApps() {
Intent mainIntent =new Intent(Intent.ACTION_MAIN, null);
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
mApps = getPackageManager().queryIntentActivities(mainIntent, 0);
}
3. 实现用于显示Gridview的Adapter，使其显示获得的应用程序列表
View Code
publicclass AppsAdapter extends BaseAdapter {
public AppsAdapter() {
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i;
if (convertView ==null) {
i =new ImageView(MyHome.this);
i.setScaleType(ImageView.ScaleType.FIT_CENTER);
i.setLayoutParams(new GridView.LayoutParams(50, 50));
} else {
i = (ImageView) convertView;
}
ResolveInfo info = mApps.get(position);
i.setImageDrawable(info.activityInfo.loadIcon(getPackageManager()));
return i;
}
publicfinalint getCount() {
return mApps.size();
}
publicfinal Object getItem(int position) {
return mApps.get(position);
}
publicfinallong getItemId(int position) {
return position;
}
4.监听GridView的onItemClick事件
设置一个监听器是为了当gridView的某项被点击时，会有一个回调函数通知我们。
我们调用mGrid.setOnItemClickListener(listener); 设置一个监听器
mGrid.setOnItemClickListener(listener)中的listener是一个接口，其类型为：android.widget.AdapterView.OnItemClickListener
private OnItemClickListener listener =new OnItemClickListener() {
@Override
publicvoid onItemClick(AdapterView<?> parent, View view, int position,long id) {
//事件内容....
}
};
5.启动被点击应用的activity
一般来讲，我们根据position即可知道被点击的项目是哪一项了。现在我们根据被点击的项目，取出对应的应用程序数据（主要是其中的主activity），然后启动activity。用下面代码实现：
publicvoid onItemClick(AdapterView<?> parent, View view, int position,long id) {
ResolveInfo info = mApps.get(position);
//该应用的包名
String pkg = info.activityInfo.packageName;
//应用的主activity类
String cls = info.activityInfo.name;
ComponentName componet =new ComponentName(pkg, cls);
Intent i =new Intent();
i.setComponent(componet);
startActivity(i);
}
最后整个Activity的代码如下：
MyHome.java
package org.bangchui.myhome;
import java.util.List;
import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.content.pm.ResolveInfo;
import android.os.Bundle;
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.AdapterView.OnItemClickListener;
publicclass MyHome extends Activity {
private List<ResolveInfo> mApps;
GridView mGrid;
private OnItemClickListener listener =new OnItemClickListener() {
@Override
publicvoid onItemClick(AdapterView<?> parent, View view, int position,long id) {
ResolveInfo info = mApps.get(position);
//该应用的包名
String pkg = info.activityInfo.packageName;
//应用的主activity类
String cls = info.activityInfo.name;
ComponentName componet =new ComponentName(pkg, cls);
Intent i =new Intent();
i.setComponent(componet);
startActivity(i);
}
};
/** Called when the activity is first created. */
@Override
publicvoid onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
loadApps();
setContentView(R.layout.main);
mGrid = (GridView) findViewById(R.id.apps_list);
mGrid.setAdapter(new AppsAdapter());
mGrid.setOnItemClickListener(listener);
}
privatevoid loadApps() {
Intent mainIntent =new Intent(Intent.ACTION_MAIN, null);
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
mApps = getPackageManager().queryIntentActivities(mainIntent, 0);
}
publicclass AppsAdapter extends BaseAdapter {
public AppsAdapter() {
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i;
if (convertView ==null) {
i =new ImageView(MyHome.this);
i.setScaleType(ImageView.ScaleType.FIT_CENTER);
i.setLayoutParams(new GridView.LayoutParams(50, 50));
} else {
i = (ImageView) convertView;
}
ResolveInfo info = mApps.get(position);
i.setImageDrawable(info.activityInfo.loadIcon(getPackageManager()));
return i;
}
publicfinalint getCount() {
return mApps.size();
}
publicfinal Object getItem(int position) {
return mApps.get(position);
}
publicfinallong getItemId(int position) {
return position;
}
}
}
