Step1
Add the following style In your res/values/styles.xml file (if you don’t have one, create it.) Here’s a complete file:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="Theme.Transparent" parent="android:Theme">
<item name="android:windowIsTranslucent">true</item>
<item name="android:windowBackground">@android:color/transparent</item>
<item name="android:windowContentOverlay">@null</item>
<item name="android:windowNoTitle">true</item>
<item name="android:windowIsFloating">true</item>
<item name="android:backgroundDimEnabled">false</item>
</style>
</resources>
(the value @color/transparent is the color value #00000000 which I put in res/values/color.xml file. You can also use @android:color/transparent in later Android versions)
Step2
Then apply the style to your activity, for example:
<activity android:name=".SampleActivity" android:theme="@style/Theme.Transparent">
...
</activity>
