RefreshIndicatorModifier class

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.

{@tool dartpad} This example shows how RefreshIndicator can be triggered in different ways.

** See code in examples/api/lib/material/refresh_indicator/refresh_indicator.0.dart ** {@end-tool}

{@tool dartpad} This example shows how to trigger RefreshIndicator in a nested scroll view using the notificationPredicate property.

** See code in examples/api/lib/material/refresh_indicator/refresh_indicator.1.dart ** {@end-tool}

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.

See also:

• material.io/design/platform-guidance/android-swipe-to-refresh.html
• RefreshIndicatorState, can be used to programmatically show the refresh indicator.
• RefreshProgressIndicator, widget used by RefreshIndicator to show the inner circular progress spinner during refreshes.
• CupertinoSliverRefreshControl, an iOS equivalent of the pull-to-refresh pattern. Must be used as a sliver inside a CustomScrollView instead of wrapping around a ScrollView because it's a part of the scrollable instead of being overlaid on top of it.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• SingleChildStatelessModifier
• RefreshIndicatorModifier

Available extensions

• ModifierTransformer

Constructors

RefreshIndicatorModifier({Key? key, Widget? child, Key? modifierKey, 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

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.

no setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

modifierKey → Key?

The actual key of the widget, which Modifier wrapped

final, inherited

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.

no setter, inherited

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

build(BuildContext context) → Widget

Describes the part of the user interface represented by this widget.

inherited

buildWithChild(BuildContext context, Widget? child) → Widget

A build method that receives an extra child parameter.

override

createElement() → SingleChildStatelessElement

Create a SingleChildStatelessElement

inherited

debugDescribeChildren() → List<DiagnosticsNode>

Returns a list of DiagnosticsNode objects describing this node's children.

inherited

debugFillProperties(DiagnosticPropertiesBuilder properties) → void

Add additional properties associated with the node.

inherited

modified() → Modifier

Available on Widget, provided by the ModifierTransformer extension

Transform normal widget to Modifier

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent 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, int wrapWidth = 65}) → 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.

inherited