Android devices come in a variety of different configurations in terms of size, pixel density display, language, etc.
Android supports automatic power source selection in accordance with the configuration of the device. For this, you provide different resources in the sub-folders specified in the directory res.
The picture below will help you understand the principles of UI is very important.
<supports-screens android:anyDensity="true" android:largeScreens="true" android:normalScreens="true" android:smallScreens="true" android:xlargeScreens="true" />
In the example code above program helps you to optimize the size of the screen when creating an android application. and this code can you input the AndroidManifest.xml file
Source: MasterAndroid (App)