Android 12 and Flutter
Android 12, released on October 4, 2021, entered our lives with plenty of changes. Therefore, we need to learn how to implement these changes in our Flutter app and which widgets or libraries we can use to implement new features. You can find here which features come and which were deprecated. Let’s start with the short video.
As you can see some features have changed. Let’s learn how to implement them.
First thing first, the splash screen has been changed, you can check out that in the document.
- The app icon should be a vector drawable image, and it can be static or animated. Although animations can have an unlimited duration, they recommend not exceeding 1,000 milliseconds. By default, the launcher icon is used.
- The icon background is optional and is useful if you need more contrast between the icon and the window background. If you use an adaptive icon, its background is displayed if there is enough contrast with the window background.
- As with adaptive icons, one-third of the foreground is masked.
- The window background consists of a single opaque color. If the window background is set and is a plain color, it is used by default if the attribute is not set.
There is a package that can help us with the splash screen.
flutter_native_splash
It is very easy to use this package, and you can provide another splash screen if the user uses another Android version or IOS. You can change the splash screen theme. In the folders, you need to create flutter_native_splash.yaml and then you can configure it.
You can check this package here.
First, add flutter_native_splash it as a dependency in your pubspec.yaml file.
flutter_native_splash:
# This package generates native code to customize Flutter's default white native splash screen
# with background color and splash image.
# Customize the parameters below, and run the following command in the terminal:
# flutter pub run flutter_native_splash:create
# To restore Flutter's default white splash screen, run the following command in the terminal:
# flutter pub run flutter_native_splash:remove
# color or background_image is the only required parameter. Use color to set the background
# of your splash screen to a solid color. Use background_image to set the background of your
# splash screen to a png image. This is useful for gradients. The image will be stretch to the
# size of the app. Only one parameter can be used, color and background_image cannot both be set.
color: "#42a5f5"
#background_image: "assets/background.png"
# Optional parameters are listed below. To enable a parameter, uncomment the line by removing
# the leading # character.
# The image parameter allows you to specify an image used in the splash screen. It must be a
# png file and should be sized for 4x pixel density.
#image: assets/splash.png
# The branding property allows you to specify an image used as branding in the splash screen.
# It must be a png file. It is supported for Android, iOS and the Web. For Android 12,
# see the Android 12 section below.
#branding: assets/dart.png
# To position the branding image at the bottom of the screen you can use bottom, bottomRight,
# and bottomLeft. The default values is bottom if not specified or specified something else.
#branding_mode: bottom
# The color_dark, background_image_dark, image_dark, branding_dark are parameters that set the background
# and image when the device is in dark mode. If they are not specified, the app will use the
# parameters from above. If the image_dark parameter is specified, color_dark or
# background_image_dark must be specified. color_dark and background_image_dark cannot both be
# set.
#color_dark: "#042a49"
#background_image_dark: "assets/dark-background.png"
#image_dark: assets/splash-invert.png
#branding_dark: assets/dart_dark.png
# Android 12 handles the splash screen differently than previous versions. Please visit
# https://developer.android.com/guide/topics/ui/splash-screen
# Following are Android 12 specific parameter.
android_12:
# The image parameter sets the splash screen icon image. If this parameter is not specified,
# the app's launcher icon will be used instead.
# Please note that the splash screen will be clipped to a circle on the center of the screen.
# App icon with an icon background: This should be 960×960 pixels, and fit within a circle
# 640 pixels in diameter.
# App icon without an icon background: This should be 1152×1152 pixels, and fit within a circle
# 768 pixels in diameter.
#image: assets/android12splash.png
# Splash screen background color.
#color: "#42a5f5"
# App icon background color.
#icon_background_color: "#111111"
# The branding property allows you to specify an image used as branding in the splash screen.
#branding: assets/dart.png
# The image_dark, color_dark, icon_background_color_dark, and branding_dark set values that
# apply when the device is in dark mode. If they are not specified, the app will use the
# parameters from above.
#image_dark: assets/android12splash-invert.png
#color_dark: "#042a49"
#icon_background_color_dark: "#eeeeee"
# The android, ios and web parameters can be used to disable generating a splash screen on a given
# platform.
#android: false
#ios: false
#web: false
# Platform specific images can be specified with the following parameters, which will override
# the respective image parameter. You may specify all, selected, or none of these parameters:
#image_android: assets/splash-android.png
#image_dark_android: assets/splash-invert-android.png
#image_ios: assets/splash-ios.png
#image_dark_ios: assets/splash-invert-ios.png
#image_web: assets/splash-web.png
#image_dark_web: assets/splash-invert-web.png
#background_image_android: "assets/background-android.png"
#background_image_dark_android: "assets/dark-background-android.png"
#background_image_ios: "assets/background-ios.png"
#background_image_dark_ios: "assets/dark-background-ios.png"
#background_image_web: "assets/background-web.png"
#background_image_dark_web: "assets/dark-background-web.png"
#branding_android: assets/brand-android.png
#branding_dark_android: assets/dart_dark-android.png
#branding_ios: assets/brand-ios.png
#branding_dark_ios: assets/dart_dark-ios.png
# The position of the splash image can be set with android_gravity, ios_content_mode, and
# web_image_mode parameters. All default to center.
#
# android_gravity can be one of the following Android Gravity (see
# https://developer.android.com/reference/android/view/Gravity): bottom, center,
# center_horizontal, center_vertical, clip_horizontal, clip_vertical, end, fill, fill_horizontal,
# fill_vertical, left, right, start, or top.
#android_gravity: center
#
# ios_content_mode can be one of the following iOS UIView.ContentMode (see
# https://developer.apple.com/documentation/uikit/uiview/contentmode): scaleToFill,
# scaleAspectFit, scaleAspectFill, center, top, bottom, left, right, topLeft, topRight,
# bottomLeft, or bottomRight.
#ios_content_mode: center
#
# web_image_mode can be one of the following modes: center, contain, stretch, and cover.
#web_image_mode: center
# The screen orientation can be set in Android with the android_screen_orientation parameter.
# Valid parameters can be found here:
# https://developer.android.com/guide/topics/manifest/activity-element#screen
#android_screen_orientation: sensorLandscape
# To hide the notification bar, use the fullscreen parameter. Has no effect in web since web
# has no notification bar. Defaults to false.
# NOTE: Unlike Android, iOS will not automatically show the notification bar when the app loads.
# To show the notification bar, add the following code to your Flutter app:
# WidgetsFlutterBinding.ensureInitialized();
# SystemChrome.setEnabledSystemUIOverlays([SystemUiOverlay.bottom, SystemUiOverlay.top]);
#fullscreen: true
# If you have changed the name(s) of your info.plist file(s), you can specify the filename(s)
# with the info_plist_files parameter. Remove only the # characters in the three lines below,
# do not remove any spaces:
#info_plist_files:
# - 'ios/Runner/Info-Debug.plist'
# - 'ios/Runner/Info-Release.plist'When you have finished the configuration you just need to run this command flutter pub run flutter_native_splash:create.
Someone made a video about it.
Dynamic Color
Dynamic color experiences are built with M3 color schemes. Beginning with Android 12, users can generate individualized schemes through wallpaper selection and other customization settings. With M3 as a foundation, user-generated colors can coexist with app colors, putting a range of customizable visual experiences in the hands of users.
Material You works in dynamic color situations like Android 12 and soon Apple iOS devices by grabbing the dominant color from wallpaper and harmonizing it with brand colors.
You can check the package here.
Android 12’s Overscroll Indicator
Android 12 changed the overscroll indicator from a glow effect to a stretch effect. Therefore, we must update our app to behave appropriately when the default appearance or behaviors change between OS versions.
Flutter 3 introduces Material Design 3 integration which offers a lot of great features to take advantage of going forward, such as dynamic themes. You can use it by setting useMaterial3 to true in ThemeData.
ThemeData(
useMaterial3: true,
…
)However, this can lead to a jarring theme transformation in your app, and will certainly affect your brand theming if you are not updating everything along with it. Plus, this will use Material Design 3 (and the stretch indicator) on all versions of Android, which isn’t really expected.
You can also implement this overscroll with using another way. I have shared the medium article about it in the source part.
A video just so you don’t have to dream about it
I wanted to write about them as I have experienced them so far. There is of course more. Maybe part 2 will come.
Source
