设置与桌面相同的action和category

安卓系统桌面也是一个activity，安卓桌面的action和category是：

<activity

    android:name="com.sxt.day04_07_twoaction.MainActivity"

    android:label="@string/app_name" >

    <intent-filter>

        <action android:name="android.intent.action.MAIN" />项目入口acticity

        <category android:name="android.intent.category.LAUNCHER" />

    </intent-filter>

</activity>

给自己的acticity设置的和桌面一样，会弹出窗口选择是启动安卓系统桌面的activity还是我们自己的activity。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical">

    <Button

        android:id="@+id/btnHome"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="启动桌面Activity" />

</LinearLayout>

package com.sxt.day04_07_twoaction;

import android.os.Bundle;

import android.app.Activity;

import android.content.Intent;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

public class MainActivity extends Activity implements OnClickListener{

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        setListener();

    }

    private void setListener() {

        findViewById(R.id.btnHome).setOnClickListener(this);

    }

    @Override

    public void onClick(View v) {

        Intent intent=new Intent();

        switch (v.getId()) {

        case R.id.btnHome:

            intent.addCategory(Intent.CATEGORY_HOME);

            intent.setAction(Intent.ACTION_MAIN);//这里用常量，也可以写字符串

            break;

        }

        startActivity(intent);

    }

}

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.sxt.day04_07_twoaction"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="18" />

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name="com.sxt.day04_07_twoaction.MainActivity"

            android:label="@string/app_name" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

        <activity

            android:name="com.sxt.day04_07_twoaction.SecondActivity"   //要启动的activity的java类

            android:label="@string/title_activity_second" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.DEFAULT"/>与桌面activity相同的时候也要加上这个，然后再设置一个category

                <category android:name="android.intent.category.HOME"/>

            </intent-filter>

        </activity>

    </application>

</manifest>

package com.sxt.day04_07_twoaction;

import android.os.Bundle;

import android.app.Activity;

import android.util.Log;

import android.view.Menu;

public class SecondActivity extends Activity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_second);  //加载xml文件

        Log.i("main","SecondActivity");

    }

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".SecondActivity" >

    <TextView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="@string/hello_world" />

</RelativeLayout>