android UI guidlines

android_assets.md

Android Assets

Basic conceptions

Apply the main stream ratio 16:9, here are the screen sizes:

• mdpi: ~160dpi, 640 x 360 px
• hdpi: ~240dpi, 960 x 540 px
• xhdpi: ~320dpi, 1280 x 720 px
• xxhdpi: ~higher, 1920 x 1080 px

A visual example of how the design mock up should look like. Normally an android app's screen is composed with:

• A status bar, the height is:
  • mdpi: 25 px
  • hdpi: 38 px
  • xhdpi: 50 px
  • xxhdpi: 76 px
• An action bar with control buttons, the height is:
  • mdpi: 48 px
  • hdpi: 64 px
  • xhdpi: 96 px
  • xxhdpi: 128 px
• The main part of the app: background image, buttons, texts & other widgets
• A virtual navigation bar (for certain devices) with the same height as the action bar.

Note: the ratio 1280 x 720 (16:9) is currently the main stream android screen ratio so we choose to base on this. Considering there are also ratio like 1280 x 800 (Galaxy Note), 1280 x 768 (Nexus 4), try to set the asset to fit the screen programmatically with relative attributes, match_parent, adjustViewBounds.

In-app images

Other

• App icon
  • mdpi: 48 x 48 px
  • hdpi: 72 x 72 px
  • xhdpi: 96 x 96 px
  • xxhdpi: 144 x 144 px

Android assets name convention

• Name the assets only with lower case letters or underscore
  • example: scan_button.png
• Put assets in mdpi/hdpi/xdpi/xxhdpi folders separately.