A month of Flutter: awesome adaptive icons

Originally published on bendyworks.com.

For this festive day of Christmas, I'm going to do something more fun and add a fancy icon. For android I will be using an adaptive icon so that it looks good in any shape and has a nice wiggle of movement.

A big thank you goes to @tommy_emo_ for creating this awesome design.

There is a nice flutter_launcher_icons package that makes the technical implementation easy.

To start, require flutter_launcher_icons as a dev_dependency in pubspec.yaml. Then there will be a new flutter_icons key added with several values.

flutter_icons:
  android: true
  ios: true
  image_path_android: assets/icon/ic_launcher_xxxhdpi.png
  image_path_ios: assets/icon/ios.png
  adaptive_icon_background: assets/icon/ic_background.png
  adaptive_icon_foreground: assets/icon/ic_foreground.png

android and ios set to true specifies that the tool should build icons for both Android and iOS.

Then there are four images defined:

image_path_android will be used for the Android app and should be a full icon with transparent edges. This will get several sizes generated by the tool so I use the xxxhdpi size as the source image.
image_path_ios will be used for the iOS app and should not have any transparent edges. It is the same as the adaptive icon but with both layers in one image.
adaptive_icon_background is the background scene of the adaptive icon. For Birb it's the sun and hills.
adaptive_icon_foreground is the forground of the adaptive icon. For Birb it's the bird.

Once those four images were added to the assets/icon directory I ran the flutter_launcher_icons tool to generate the correct assets and added all the changes to git.

$ flutter packages pub run flutter_launcher_icons:main
Android minSdkVersion = 16
Creating default icons Android
Overwriting the default Android launcher icon with a new icon
Creating adaptive icons Android
Overwriting default iOS launcher icon with new icon

The new icon on Android's home screen with a rounded square shape: