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;
  (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 {
    Future.value().then((_) {
      headerMode!.value = RefreshStatus.refreshing;
    });
  }
}