Android Activity 悬浮 半透明边框

1、首先来创建一个Activity，在Activity的OnCreate函数里面我们设置它为全屏，然后设置Activity的宽高为全屏*0.9，然后设置背景图片为半透明的 .9 图片 。这样就已经是非全屏的窗体了

		this.requestWindowFeature(Window.FEATURE_NO_TITLE);

		this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
				WindowManager.LayoutParams.FLAG_FULLSCREEN);

		setContentView(R.layout.activity_webview);
		
		WindowManager windowManager=getWindowManager();
		Display display=windowManager.getDefaultDisplay();
		LayoutParams params=getWindow().getAttributes();
		params.height=(int)(display.getHeight()*0.9);
		params.width=(int)(display.getWidth()*0.9);
		params.alpha=1.0f;
		getWindow().setAttributes(params);
		getWindow().setGravity(Gravity.CENTER);
		getWindow().setBackgroundDrawableResource(R.drawable.webviewbg);

        <!-- webview theme -->
    <style name="webviewTheme" parent="@android:style/Theme.Translucent.NoTitleBar.Fullscreen">
       		<item name="android:windowFrame">@null</item><!--边框-->
		<item name="android:windowIsFloating">true</item><!--是否浮如今activity之上-->
		<item name="android:windowIsTranslucent">false</item><!--半透明-->
		<item name="android:windowNoTitle">true</item><!--无标题-->
		<item name="android:background">@android:color/transparent</item>
		<item name="android:windowBackground">@android:color/transparent</item><!--背景透明-->
		<item name="android:backgroundDimEnabled">false</item><!--模糊-->
    </style>

      <activity
            android:name="com.crystal.geart3d.WebviewActivity"
            android:screenOrientation="landscape"
            android:theme="@style/webviewTheme" >
        </activity>