调用空白Acitivity: 

BlankActivity.Show(this);
package sc.tool.screen;

import .Activity;
import android.content.Intent;
import android.os.Bundle;


/** manifest中添加配置:
	<activity
		android:name="sc.tool.screen.BlankActivity"
		android:configChanges="orientation|keyboardHidden|screenSize" 
		android:theme="@android:style/Theme.Translucent.NoTitleBar.Fullscreen"/>
*/

/** 背景透明的Activity */
public class BlankActivity extends Activity
{
	protected void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		// setContentView(null);
	}
	
	/** 显示当前Activity */
	public static void Show(Activity context)
	{
		context.finish();	// 关闭context对应的Activity
		
		Intent intent = new Intent(context, BlankActivity.class);
		context.startActivity(intent);
	}
}

在Manifest.XML中的声明:

<activity
    android:name="sc.tool.screen.BlankActivity"
    android:configChanges="orientation|keyboardHidden|screenSize" 
    android:theme="@android:style/Theme.Translucent.NoTitleBar.Fullscreen"/>

显示一个背景透明的空白Activity在屏幕上。