flutter native splash が便利だった

作成日: 2024-02-01 /

概要

新しいアプリを作成するときのスプラッシュ画像の設定のやり方を書く。flutter_native_splash を採用した結果、非常に便利だったので、使ってみた感想をまとめる。

flutter_native_splash | Flutter package

flutter_native_splash | Flutter package

https://pub.dev

flutter_native_splash | Flutter package

モチベーション

Android 12 以降の OS で新しく SplashScreen API が導入された。早速変更を追従しようとしたが、OS のバージョンの変更に全て毎回追従していくよりも、変更するコストを下げられることを期待し、使用することに決めた。今回の SplashScreen API に対しても互換性があるので、より採用する。

https://developer.android.com/develop/ui/views/launch/splash-screen?hl=ja

https://developer.android.com

1 つのスプラッシュ画像からコマンド 1 つで、様々なサイズの画像を出力してくれるのが非常に便利。適切な大きさの画像を適切な場所に配置するコストもなくなるので、手作業がなくなる。

スプラッシュ画像の表示と非表示にする API も用意されているので、任意のタイミングで実行できるカスタマイズ性もあり。今回は使用することがなかったので、これは割愛。flavor 対応もできるみたいだが、開発、ステージング、本番環境によって特にスプラッシュ画像を変更する必要はないので、flavor 対応は行わない。

事前準備

  • Flutter: 3.19.6
  • flutter_native_splash: 2.4.0
  • スプラッシュ用の画像
    • 今回 Splash Screen API に合わせた方がいいことから、大枠で 1152 x 1152 の画像を用意し、その中で直径 768px の画像を用意する。(参照)

設定

デフォルトの flutter_native_splash の設定ファイルがこちらになる。

flutter_native_splash.yml
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:
  # dart run flutter_native_splash:create
  # To restore Flutter's default white splash screen, run the following command in the terminal:
  # dart run flutter_native_splash:remove

  # IMPORTANT NOTE: These parameter do not affect the configuration of Android 12 and later, which
  # handle splash screens differently that prior versions of Android.  Android 12 and later must be
  # configured specifically in the android_12 section below.

  # 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: "#ffffff"
  #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/image.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

  # Set the branding padding from the bottom of the screen.  The default value is 0
  # branding_bottom_padding: 24

  # 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

  # From Android 12 onwards, the splash screen is handled differently than in previous versions.
  # Please visit https://developer.android.com/guide/topics/ui/splash-screen
  # Following are specific parameters for Android 12+.
  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/splash/image.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: true
  ios: true
  #web: false

  # Platform specific images can be specified with the following parameters, which will override
  # the respective parameter.  You may specify all, selected, or none of these parameters:
  #color_android: "#42a5f5"
  #color_dark_android: "#042a49"
  #color_ios: "#42a5f5"
  #color_dark_ios: "#042a49"
  #color_web: "#42a5f5"
  #color_dark_web: "#042a49"
  #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.gif
  #image_dark_web: assets/splash-invert-web.gif
  #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_bottom_padding_android: 24
  #branding_dark_android: assets/dart_dark-android.png
  #branding_ios: assets/brand-ios.png
  #branding_bottom_padding_ios: 24
  #branding_dark_ios: assets/dart_dark-ios.png
  #branding_web: assets/brand-web.gif
  #branding_dark_web: assets/dart_dark-web.gif

  # 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.setEnabledSystemUIMode(SystemUiMode.manual, overlays: [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'

実行

アプリディレクトリ下で下記のコマンドを実行する。 設定ファイルを更新するたびに、下のコマンドを実行するのをお忘れないように。

$ fvm flutter pub get
$ fvm flutter pub run flutter_native_splash:create

自動で iOS / Android の assets ディレクトリに画像が設定される。Android で既存の非 Splash Screen API 用と Splash Screen API 用、それぞれの画像が出力されたことを確認。どこに出力されるなどを見ると、スプラッシュ画像の知見が増えそう。

  $ fvm flutter pub run flutter_native_splash:create
[Android] Creating default splash images
[Android] Creating default android12splash images
[Android] Creating dark mode android12splash images
[Android] Updating launch background(s) with splash image path...
[Android]  - android/app/src/main/res/drawable/launch_background.xml
[Android]  - android/app/src/main/res/drawable-v21/launch_background.xml
[Android] Updating styles...
[Android]  - android/app/src/main/res/values-v31/styles.xml
[Android]  - android/app/src/main/res/values-night-v31/styles.xml
[Android]  - android/app/src/main/res/values/styles.xml
[Android]  - android/app/src/main/res/values-night/styles.xml
[iOS] Creating  images
[iOS] Updating ios/Runner/Info.plist for status bar hidden/visible
Web folder not found, skipping web splash update...

 Native splash complete.
Now go finish building something awesome! 💪 You rock! 🤘🤩
Like the package? Please give it a 👍 here: https://pub.dev/packages/flutter_native_splash

まとめ

採用する価値を非常に感じたライブラリでした。手作業をなくす、新しい API キャッチアップのコストを下げられるなどペインを一気になくせたのが魅力的でした。使わなかった機能が多いので、使う機会があったら更新していく。