Flutter Custom Refresh Indicator

This package provides CustomRefreshIndicator widget that make it easy to implement your own custom refresh indicator. It listens for scroll events from scroll widget passed to child argument and parsing it to data easy for custom refresh indicator implementation. Indicator data is provided by IndicatorController (third argument of builder method). Long story short... thats it!

If there is something that can be improved, fixed or you just have some great idea feel free to open github issue HERE or open a pull request HERE.

If you implemented your own custom refresh indicator with this library and you want it to be mentioned here or provided as an example to the eample app, just open a pull request HERE.

QUICK START

Code

CustomRefreshIndicator(
  /// Scrollable widget
  child: ListView.separated(
    itemBuilder: (BuildContext context, int index) => const SizedBox(
      height: 100,
    ),
    separatorBuilder: (BuildContext context, int index) =>
        const SizedBox(height: 20),
  ),
  /// Custom indicator builder function
  builder: (
    BuildContext context,
    Widget child,
    IndicatorController controller,
    ) {
      /// TODO: Implement your own refresh indicator
      return Stack(
        children: <Widget>[
          AnimatedBuilder(
            animation: controller,
            builder: (BuildContext context, _) {
              /// This part will be rebuild on every controller change
              return MyIndicator();
            },
          ),
          /// Scrollable widget that was provided as [child] argument
          ///
          /// TIP:
          /// You can also wrap [child] with [Transform] widget to also a animate list transform (see example app)
          child,
        ],
      );
    }
  /// A function that's called when the user has dragged the refresh indicator
  /// far enough to demonstrate that they want the app to refresh.
  /// Should return [Future].
  onRefresh: myAsyncRefreshMethod,
)

How the controller data change

The best way to understand how the "CustomRefreshIndicator" widget changes its controller data is to see the example 😉. An example is available in the example application.

Controller_Data

Examples

Almost all of these examples are available in the example application.

Plane indicator [SOURCE CODE]

plane_indicator

Ice cream indicator [SOURCE CODE]

ice_cream_indicator

Simple indicator made with PositionedIndicatorContainer [SOURCE CODE]

simple_indicator

Envelope indicator

letter_indicator

Emoji indicator [SOURCE CODE]

You can create any indicator you want!

letter_indicator

CustomRefreshIndicator widget

CustomRefreshIndicator widget provides an absolute minimum functionality that allows you to create and set your own custom indicators.

IndicatorState

Enum which describes state of CustomRefreshIndicator. It is provided by IndicatorController.

idle

CustomRefreshIndicator is idle (There is no action)

controller.value == 0.0

dragging

Whether the user is dragging a scrollable widget.
Ending the scroll WILL NOT result in onRefresh function call

controller.value < 1.0

armed

CustomRefreshIndicator is armed ending the scroll WILL result in:

  • onRefresh function call
  • change of indicator status to loading
  • decreasing controller.value to 1.0 in duration specified by armedToLoadingDuration CustomRefreshIndicator widget argument
controller.value >= 1.0

hiding

CustomRefreshIndicator is hiding its indicator. After the future returned from onRefresh function is completed or scroll ended when the state was equal to dragging or the user started scrolling through the list. controller value decreases to 0.0 in duration specified by draggingToIdleDuration CustomRefreshIndicator widget argument.

controller.value <= 1.0

loading

CustomRefreshIndicator widget is awaiting on future returned from onRefresh function. After future completed state will be change into hiding and controller value will decrease from 1.0 to 0.0 in duration specified by loadingToIdleDuration CustomRefreshIndicator widget argument.

controller.value == 1.0

Libraries

custom_refresh_indicator