Switch constructor Null safety
- {Key? key,
- required bool value,
- required ValueChanged<
bool> ? onChanged, - Color? activeColor,
- Color? activeTrackColor,
- Color? inactiveThumbColor,
- Color? inactiveTrackColor,
- ImageProvider<
Object> ? activeThumbImage, - ImageErrorListener? onActiveThumbImageError,
- ImageProvider<
Object> ? inactiveThumbImage, - ImageErrorListener? onInactiveThumbImageError,
- MaterialStateProperty<
Color?> ? thumbColor, - MaterialStateProperty<
Color?> ? trackColor, - MaterialTapTargetSize? materialTapTargetSize,
- DragStartBehavior dragStartBehavior = DragStartBehavior.start,
- MouseCursor? mouseCursor,
- Color? focusColor,
- Color? hoverColor,
- MaterialStateProperty<
Color?> ? overlayColor, - double? splashRadius,
- FocusNode? focusNode,
- bool autofocus = false}
Creates a Material Design switch.
The switch itself does not maintain any state. Instead, when the state of
the switch changes, the widget calls the onChanged callback. Most widgets
that use a switch will listen for the onChanged callback and rebuild the
switch with a new value
to update the visual appearance of the switch.
The following arguments are required:
value
determines whether this switch is on or off.- onChanged is called when the user toggles the switch on or off.
Implementation
const Switch({
super.key,
required this.value,
required this.onChanged,
this.activeColor,
this.activeTrackColor,
this.inactiveThumbColor,
this.inactiveTrackColor,
this.activeThumbImage,
this.onActiveThumbImageError,
this.inactiveThumbImage,
this.onInactiveThumbImageError,
this.thumbColor,
this.trackColor,
this.materialTapTargetSize,
this.dragStartBehavior = DragStartBehavior.start,
this.mouseCursor,
this.focusColor,
this.hoverColor,
this.overlayColor,
this.splashRadius,
this.focusNode,
this.autofocus = false,
}) : _switchType = _SwitchType.material,
assert(dragStartBehavior != null),
assert(activeThumbImage != null || onActiveThumbImageError == null),
assert(inactiveThumbImage != null || onInactiveThumbImageError == null);