requestRefresh method

Future<void>? requestRefresh({ bool needMove = true, bool needCallback = true, Duration duration = const Duration(milliseconds: 500), Curve curve = Curves.linear, })

make the header enter refreshing state,and callback onRefresh

Implementation

Future<void>? requestRefresh(
    {bool needMove = true,
    bool needCallback = true,
    Duration duration = const Duration(milliseconds: 500),
    Curve curve = Curves.linear}) {
  assert(position != null,
      'Try not to call requestRefresh() before build,please call after the ui was rendered');
  if (isRefresh) return Future.value();
  StatefulElement? indicatorElement =
      _findIndicator(position!.context.storageContext, RefreshIndicator);

  if (indicatorElement == null || _refresherState == null) {
    return null;
  } else {
    (indicatorElement.state as RefreshIndicatorState).floating = true;

    if (needMove && _refresherState!.mounted) {
      _refresherState!.setCanDrag(false);
    }
    if (needMove) {
      return Future.delayed(const Duration(milliseconds: 50)).then((_) async {
        // - 0.0001 is for NestedScrollView.
        await position
            ?.animateTo(position!.minScrollExtent - 0.0001,
                duration: duration, curve: curve)
            .then((_) {
          if (_refresherState != null && _refresherState!.mounted) {
            _refresherState!.setCanDrag(true);
            if (needCallback) {
              headerMode!.value = RefreshStatus.refreshing;
            } else {
              headerMode!.setValueWithNoNotify(RefreshStatus.refreshing);
              if (indicatorElement.state.mounted) {
                (indicatorElement.state as RefreshIndicatorState)
                    .setState(() {});
              }
            }
          }
        });
      });
    } else {
      return Future.value().then((_) {
        headerMode!.value = RefreshStatus.refreshing;
      });
    }
  }
}