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
<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="org.bangchui.myhome" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".MyHome" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> <category android:name="android.intent.category.HOME" /> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> </activity> </application></manifest>
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
private void 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
public class 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; } public final int getCount() { return mApps.size(); } public final Object getItem(int position) { return mApps.get(position); } public final long 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() {@Overridepublic void 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：
public void 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;public class MyHome extends Activity { private List<ResolveInfo> mApps; GridView mGrid; private OnItemClickListener listener = new OnItemClickListener() { @Override public void 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 public void 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); } private void loadApps() { Intent mainIntent = new Intent(Intent.ACTION_MAIN, null); mainIntent.addCategory(Intent.CATEGORY_LAUNCHER); mApps = getPackageManager().queryIntentActivities(mainIntent, 0); } public class 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; } public final int getCount() { return mApps.size(); } public final Object getItem(int position) { return mApps.get(position); } public final long getItemId(int position) { return position; } }}
来源：https://www.cnblogs.com/playing/archive/2011/04/13/2014705.html