black_hole_flutter

🛠 A package absorbing all Flutter utility functions, including extension functions and commonly used widgets.

• 📄 Bottom Sheet
• 🏗 BuildContext
• 🎨 Colors
  • 🌈 Material Design colors
• 🧭 Navigation
• 📱 Widgets
  • 🔳 Buttons
  • 🥙 FillOrWrap
  • 🎯 LeftCenterRight
  • 🟢 Circle
• 🖼 RenderObject
• ↕ Size

📄 Bottom Sheet

Show modal bottom sheets using: context.showModalBottomSheet().

Also, this package adds a custom FancyBottomSheet with a drag indicator at the top. You can create one using context.showFancyModalBottomSheet().

🏗 BuildContext

In Flutter, you often see the pattern <Class>.of(context) (e.g., Theme.of(context)). This package adds extension getters on BuildContext for those classes so you can just say:

Extension	Shortcut for
context.colorScheme	ColorScheme.of(context)
context.defaultTextStyle	DefaultTextStyle.of(context)
context.directionality	Directionality.of(context)
context.form	Form.of(context)
context.locale	Localizations.localeOf(context)
context.materialLocalizations	MaterialLocalizations.of(context)
context.mediaQuery	MediaQuery.of(context)
context.overlay	Overlay.of(context)
context.pageStorage	PageStorage.of(context)
context.scaffold	Scaffold.of(context)
context.scaffoldOrNull	Scaffold.of(context, nullOk: true)
context.textTheme	TextTheme.of(context)
context.theme	Theme.of(context)

🎨 Colors

Handy extensions on Brightness:

Extension	Explanation
brightness.isDark	≙ brightness == Brightness.dark
brightness.isLight	≙ brightness == Brightness.light
brightness.opposite	opposite Brightness
brightness.color	Color representing this brightness, i.e.: · Colors.white for Brightness.light · Colors.black for Brightness.dark
brightness.contrastColor	opposite of brightness.color (above)

isDark, isLight, and contrastColor can also be used on ThemeData directly.

Handy extensions on Color:

Extension	Explanation
color.estimatedBrightness	estimated Brightness based on color's luminance
color.isOpaque	if opacity is 1.0
color.alphaBlendOn(Color background)	resulting Color when drawing color on top of background
color.withAdditionalOpacity(double opacity)	applies opacity by multiplying it to the existing opacity
color.withAdditionalAlpha(int alpha)	like above, but with an integer alpha
color.hsl	≙ HSLColor.fromColor(color)
color.hsv	≙ HSVColor.fromColor(color)

And if you can't decide on a color, just use random.nextColor(), random.nextColorHsl() or random.nextColorHsv()!

Convert between alpha and opacity with int.alphaToOpacity and double.opacityToAlpha.

🌈 Material Design colors

Material Design specifies different opacities of white and black colors to use for text of different emphases on colored backgrounds. You can now use the highEmphasisOnColor, mediumEmphasisOnColor and disabledOnColor extension getters on Color to make your text legible! The raw opacity values are also available as MaterialColors.highEmphasisTextAlpha, MaterialColors.mediumEmphasisTextAlpha, and MaterialColors.disabledTextAlpha.

🧭 Navigation

Access your navigation-related information via extension methods:

Extension	Shortcut for
context.navigator	Navigator.of(context)
context.rootNavigator	Navigator.of(this, rootNavigator: true)
context.modalRoute	ModalRoute.of(context)

Push a new route and pop all previous routes (e.g., when signing out the user):

navigator.pushAndRemoveAll(/* new route */);
// Or using a named route:
navigator.pushNamedAndRemoveAll(/* route name */);

Log navigation events to the console:

MaterialApp(
  navigatorObservers: [LoggingNavigatorObserver()],
  // ...
)
// Prints:
// Navigator: didPush /dashboard → /articles/12345
// Navigator: didPop /dashboard ← /articles/12345

Note: This uses the name of routes, so it only works with named routes.

📱 Widgets

🔳 Buttons

Did you ever want to show a progress indicator inside a button? Or were annoyed to conditionally set a Button's onPressed to disable it? Fear no more — black_hole_flutter has got you covered!

^{This screenshot only shows an excerpt of all available button types and variants.}

In FancyFab (a FloatingActionButton), FancyTextButton, FancyOutlinedButton, FancyElevatedButton, FancyFilledButton, and FancyIconButton, we introduce some new parameters:

• isLoading: Setting this to true shows a CircularProgressIndicator and disables this button. You can optionally specify a loadingChild (loadingLabel on FancyFab) to show next to the progress indicator.
• isEnabled: Settings this to false disables this button, even if onPressed is set.

🥙 FillOrWrap

A layout with two different behaviors:

• By default, all children are positioned next to each other with equal widths. This is comparable to a Row with all children wrapped in Expanded.
• If the children are too wide to fit in a single line, or one child would become smaller than its reported minimum width, the children get positioned below each other ("wrapped"). This is similar to a Column with MainAxisSize.min.

🎯 LeftCenterRight

A layout taking optional left, center, and right children. It will try to keep center in the center of itself, even if only one of left and right is set, or they have different widths.

🟢 Circle

A circle with optional diameter, background color, padding, and child.

🖼 RenderObject

When writing a custom layout, you might find this extension on ContainerRenderObjectMixin useful:

Extension	Explanation
containerRenderObjectMixin.children	Returns all children using firstChild and childAfter

↕ Size

Extension	Explanation
size.diagonal	length of the diagonal of a rectangle with this Size
size.squaredDiagonal	≙ size.diagonal * size.diagonal
size.coerceAtLeast(Size minimum)	Ensures size is not smaller than minimum in any axis
size.coerceAtMost(Size maximum)	Ensures size is not larger than minimum in any axis