RefreshIndicator({Key key, GlobalKey<ScrollableState> scrollableKey, Widget child, double displacement: 40.0, RefreshCallback refresh, RefreshIndicatorLocation location: RefreshIndicatorLocation.top, Color color, Color backgroundColor })

Creates a refresh indicator.

The refresh and child arguments must be non-null. The default displacement is 40.0 logical pixels.

Source 

RefreshIndicator({
  Key key,
  this.scrollableKey,
  this.child,
  this.displacement: 40.0,
  this.refresh,
  this.location: RefreshIndicatorLocation.top,
  this.color,
  this.backgroundColor
}) : super(key: key) {
  assert(child != null);
  assert(refresh != null);
  assert(location != null);
}