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公告

 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
2 . 通过PackageManager的api 查询已经安装的apk
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() {
@Override
public 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;
        }
    }
}

posted on 2011-04-13 13:01 山岭巨人 阅读(...) 评论(...) 编辑 收藏