RefreshIndicator class Null safety

A widget that supports the Material "swipe to refresh" idiom.

When the child's Scrollable descendant overscrolls, an animated circular progress indicator is faded into view. When the scroll ends, if the indicator has been dragged far enough for it to become completely opaque, the onRefresh callback is called. The callback is expected to update the scrollable's contents and then complete the Future it returns. The refresh indicator disappears after the callback's Future has completed.

The trigger mode is configured by RefreshIndicator.triggerMode.

This example shows how RefreshIndicator can be triggered in different ways.

To create a local project with this code sample, run:
flutter create --sample=material.RefreshIndicator.1 mysample

This example shows how to trigger RefreshIndicator in a nested scroll view using the notificationPredicate property.

To create a local project with this code sample, run:
flutter create --sample=material.RefreshIndicator.2 mysample

Troubleshooting

Refresh indicator does not show up

The RefreshIndicator will appear if its scrollable descendant can be overscrolled, i.e. if the scrollable's content is bigger than its viewport. To ensure that the RefreshIndicator will always appear, even if the scrollable's content fits within its viewport, set the scrollable's Scrollable.physics property to AlwaysScrollableScrollPhysics:

ListView(
  physics: const AlwaysScrollableScrollPhysics(),
  children: ...
)

A RefreshIndicator can only be used with a vertical scroll view.

Constructors

RefreshIndicator({Key? key, required Widget child, double displacement = 40.0, double edgeOffset = 0.0, required RefreshCallback onRefresh, Color? color, Color? backgroundColor, ScrollNotificationPredicate notificationPredicate = defaultScrollNotificationPredicate, String? semanticsLabel, String? semanticsValue, double strokeWidth = RefreshProgressIndicator.defaultStrokeWidth, RefreshIndicatorTriggerMode triggerMode = RefreshIndicatorTriggerMode.onEdge}): Creates a refresh indicator.
const

Properties

backgroundColor → Color?: The progress indicator's background color. The current theme's ThemeData.canvasColor by default.
final
child → Widget: The widget below this widget in the tree.
final
color → Color?: The progress indicator's foreground color. The current theme's ColorScheme.primary by default.
final
displacement → double: The distance from the child's top or bottom edgeOffset where the refresh indicator will settle. During the drag that exposes the refresh indicator, its actual displacement may significantly exceed this value.
final
edgeOffset → double: The offset where RefreshProgressIndicator starts to appear on drag start.
final
hashCode → int: The hash code for this object.
nonVirtual">@nonVirtualread-onlyinherited
key → Key?: Controls how one widget replaces another widget in the tree.
finalinherited
notificationPredicate → ScrollNotificationPredicate: A check that specifies whether a ScrollNotification should be handled by this widget.
final
onRefresh → RefreshCallback: A function that's called when the user has dragged the refresh indicator far enough to demonstrate that they want the app to refresh. The returned Future must complete when the refresh operation is finished.
final
runtimeType → Type: A representation of the runtime type of the object.
read-onlyinherited
semanticsLabel → String?: The SemanticsProperties.label for this progress indicator.
final
semanticsValue → String?: The SemanticsProperties.value for this progress indicator.
final
strokeWidth → double: Defines strokeWidth for RefreshIndicator.
final
triggerMode → RefreshIndicatorTriggerMode: Defines how this RefreshIndicator can be triggered when users overscroll.
final

Methods

createElement() → StatefulElement: Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → RefreshIndicatorState: Creates the mutable state for this widget at a given location in the tree.
override
debugDescribeChildren() → List<DiagnosticsNode>: Returns a list of DiagnosticsNode objects describing this node's children.
protected">@protectedinherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a non-existent method or property is accessed.
inherited
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode: Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
inherited
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String: A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String: Returns a string representation of this node and its descendants.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String: Returns a one-line detailed description of the object.
inherited
toStringShort() → String: A short, textual description of this widget.
inherited

Operators

operator ==(Object other) → bool: The equality operator.
nonVirtual">@nonVirtualinherited

Flutter
material
RefreshIndicator class