v3.19 後已移除棄用 API

// TextTheme
// Base constructor
TextTheme(
  headline1: headline1Style,
  headline2: headline2Style,
  headline3: headline3Style,
  headline4: headline4Style,
  headline5: headline5Style,
  headline6: headline6Style,
  subtitle1: subtitle1Style,
  subtitle2: subtitle2Style,
  bodyText1: bodyText1Style,
  bodyText2: bodyText2Style,
  caption: captionStyle,
  button: buttonStyle,
  overline: overlineStyle,
);

// copyWith
TextTheme.copyWith(
  headline1: headline1Style,
  headline2: headline2Style,
  headline3: headline3Style,
  headline4: headline4Style,
  headline5: headline5Style,
  headline6: headline6Style,
  subtitle1: subtitle1Style,
  subtitle2: subtitle2Style,
  bodyText1: bodyText1Style,
  bodyText2: bodyText2Style,
  caption: captionStyle,
  button: buttonStyle,
  overline: overlineStyle,
);

// Getters
TextStyle style;
style = textTheme.headline1,
style = textTheme.headline2,
style = textTheme.headline3,
style = textTheme.headline4,
style = textTheme.headline5,
style = textTheme.headline6,
style = textTheme.subtitle1,
style = textTheme.subtitle2,
style = textTheme.bodyText1,
style = textTheme.bodyText2,
style = textTheme.caption,
style = textTheme.button,
style = textTheme.overline,

// TextTheme
// Base constructor
TextTheme(
  displayLarge: headline1Style,
  displayMedium: headline2Style,
  displaySmall: headline3Style,
  headlineMedium: headline4Style,
  headlineSmall: headline5Style,
  titleLarge: headline6Style,
  titleMedium: subtitle1Style,
  titleSmall: subtitle2Style,
  bodyLarge: bodyText1Style,
  bodyMedium: bodyText2Style,
  bodySmall: captionStyle,
  labelLarge: buttonStyle,
  labelSmall: overlineStyle,
);

TextTheme.copyWith(
  displayLarge: headline1Style,
  displayMedium: headline2Style,
  displaySmall: headline3Style,
  headlineMedium: headline4Style,
  headlineSmall: headline5Style,
  titleLarge: headline6Style,
  titleMedium: subtitle1Style,
  titleSmall: subtitle2Style,
  bodyLarge: bodyText1Style,
  bodyMedium: bodyText2Style,
  bodySmall: captionStyle,
  labelLarge: buttonStyle,
  labelSmall: overlineStyle,
);

TextStyle style;
style = textTheme.displayLarge;
style = textTheme.displayMedium;
style = textTheme.displaySmall;
style = textTheme.headlineMedium;
style = textTheme.headlineSmall;
style = textTheme.titleLarge;
style = textTheme.titleMedium;
style = textTheme.titleSmall;
style = textTheme.bodyLarge;
style = textTheme.bodyMedium;
style = textTheme.bodySmall;
style = textTheme.labelLarge;
style = textTheme.labelSmall;

var myTheme = ThemeData(
  //...
  errorColor: Colors.red,
  backgroundColor: Colors.blue,
  bottomAppBarColor: Colors.purple,
  toggleableActiveColor: Colors.orange,
  //...
);
var errorColor = myTheme.errorColor;
var backgroundColor = myTheme.backgroundColor;
var bottomAppBarColor = myTheme.bottomAppBarColor;
var toggleableActiveColor = myTheme.toggleableActiveColor;

var myTheme = ThemeData(
  //...
  colorScheme: ColorScheme(
    /// ...
    error: Colors.red,
    background: Colors.blue,
  ),
  bottomAppBarTheme: BottomAppBarTheme(
    color: Colors.purple,
  ),
  //...
);
var errorColor = myTheme.colorScheme.error;
var backgroundColor = myTheme.colorScheme.background;
var bottomAppBarColor = myTheme.bottomAppBarTheme.color;
var toggleableActiveColor = Colors.orange;

CupertinoContextMenu(
  previewBuilder: (BuildContext context, Animation<double> animation, Widget child) {
    return FittedBox(
      fit: BoxFit.cover,
      child: ClipRRect(
        borderRadius: BorderRadius.circular(64.0 * animation.value),
        child: Image.asset('assets/photo.jpg'),
      ),
    );
  },
  actions: <Widget>[
    CupertinoContextMenuAction(
      child: const Text('Action one'),
      onPressed: () {},
    ),
  ],
  child: FittedBox(
    fit: BoxFit.cover,
    child: Image.asset('assets/photo.jpg'),
  ),
);

CupertinoContextMenu(
  actions: <Widget>[
    CupertinoContextMenuAction(
      child: const Text('Action one'),
      onPressed: () {},
    ),
  ],
  builder: (BuildContext context, Animation<double> animation) {
    final Animation<BorderRadius?> borderRadiusAnimation = BorderRadiusTween(
      begin: BorderRadius.circular(0.0),
      end: BorderRadius.circular(CupertinoContextMenu.kOpenBorderRadius),
    ).animate(
      CurvedAnimation(
        parent: animation,
        curve: Interval(
          CupertinoContextMenu.animationOpensAt,
          1.0,
        ),
      ),
    );

    final Animation<Decoration> boxDecorationAnimation = DecorationTween(
      begin: const BoxDecoration(
        color: Color(0xFFFFFFFF),
        boxShadow: <BoxShadow>[],
      ),
      end: BoxDecoration(
        color: Color(0xFFFFFFFF),
        boxShadow: CupertinoContextMenu.kEndBoxShadow,
      ),
    ).animate(
      CurvedAnimation(
        parent: animation,
        curve: Interval(
          0.0,
          CupertinoContextMenu.animationOpensAt,
        )
      )
    );

    return Container(
      decoration: animation.value < CupertinoContextMenu.animationOpensAt
        ? boxDecorationAnimation.value
        : null,
      child: FittedBox(
        fit: BoxFit.cover,
        child: ClipRRect(
          borderRadius: borderRadiusAnimation.value ?? BorderRadius.circular(0.0),
          child: SizedBox(
            height: 150,
            width: 150,
            child: Image.asset('assets/photo.jpg'),
          ),
        ),
      )
    );
   }
 )

Scrollbar(
  showTrackOnHover: true,
  child: //...
);
ScrollbarThemeData(
  showTrackOnHover: true,
);

Scrollbar(
  child: //...
);
ScrollbarThemeData(
  // This will always show the track for any state.
  trackVisibility: MaterialStateProperty<bool>.all(true),
);
// Or
ScrollbarThemeData(
  // Only show on hover.
  trackVisibility: (Set<MaterialState> states) => states.contains(MaterialState.hovered),
);

KeepAliveHandle handle = KeepAliveHandle();
handle.release();
handle.dispose();

KeepAliveHandle handle = KeepAliveHandle();
handle.dispose();

InteractiveViewer(
  alignPanAxis: true,
);

InteractiveViewer(
  panAxis: PanAxis.aligned,
);

MediaQuery.boldTextOverride(context);

MediaQuery.boldTextOf(context)

FlutterDriver driver = FlutterDriver.connectedTo(
  // ...
);
driver.enableAccessibility();

FlutterDriver driver = FlutterDriver.connectedTo(
  // ...
);
driver.setSemantics(true);

TimelineSummary summary = TimelineSummary.summarize(
  myTimeline,
);
summary.writeSummaryToFile(
  traceName,
  pretty: true,
);

TimelineSummary summary = TimelineSummary.summarize(
  myTimeline,
);
summary.writeTimelineToFile(
  traceName,
  pretty: true,
);