Other practices

Maximum aspect ratio

The cover display will have a long (21:9) aspect ratio.

So the application needs to handle a maximum aspect ratio to fill the entire screen.

The public guide is found in the Android developer site:

https://developer.android.com/guide/practices/screens-distribution#MaxAspectRatio

In the guideline, you can choose the following options to support aspect ratio.

  1. Declare the target SDK version

    Apps that targets Android 8.0 (API level 26) or higher, they will fill the entire screen.

  2. Declare the resizeableActivity

    If the activity is resizable, your Activity will fill the entire screen.

    Code Block 2 Set attribute in your manifest's <activity> or <application> element

    android:resizeableActivity=["true" | "false"]
    
  3. Declare a max aspect ratio

    For Android 7.1 and lower, add a element named android.max_aspect in the element.

    Code Block 3 meta-data android.max_aspect

    <!-- Render on full screen up to screen aspect ratio of 2.4 -->
    <!-- Use a letterbox on screens larger than 2.4 -->
    <meta-data android:name="android.max_aspect" android:value="2.4" />
    
Optimized layouts for cover display and main display

Now the app will run in both displays even with different sizes.

We recommend adding a separate resource folder to show more rich and clear content.

How to optimize layouts

Refer to the following link to get the default information about separate resource folder.

https://developer.android.com/guide/practices/screens_support

Reference display configuration

See the foldable device configurations below for each display.

Cover display Main display
smallest width 320 dp 585 dp
screen size 840 x 1960 1536 x 2152
screen layout SCREENLAYOUT_SIZE_NORMAL
SCREENLAYOUT_LONG_YES

SCREENLAYOUT_SIZE_LARGE
SCREENLAYOUT_LONG_NO