Android--將Activity設置成Dialog

package com.mrzhu.dialogtest;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;

public class DialogTestActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    public void click(View v){
        startActivity(new Intent(DialogTestActivity.this, Activity2.class));
    }
}

package com.mrzhu.dialogtest;

import android.app.Activity;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;
import android.view.WindowManager.LayoutParams;

public class Activity2 extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity2);
        Window window = getWindow();
        WindowManager.LayoutParams layoutParams = window.getAttributes();
        //設置窗口的大小及透明度
        layoutParams.width = LayoutParams.FILL_PARENT;
        layoutParams.height = layoutParams.FILL_PARENT;
        layoutParams.alpha = 0.5f;
        window.setAttributes(layoutParams);
    }
}

AndroidManifest.xml中加入：

 <activity
            android:name=".Activity2"
            android:theme="@style/Transparent" >
        </activity>

style.xml:

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

    <style name="Transparent" parent="android:style/Theme.Dialog">
        <item name="android:windowNoTitle">true</item>
        <item name="android:windowIsTranslucent">true</item>
        <item name="android:windowAnimationStyle">@+android:style/Animation.Translucent</item>
    </style>

</resources>

main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:onClick="click"
        android:text="click" />

</LinearLayout>