Tooltip({Key key, String message, double height: 32.0, EdgeInsets padding: const EdgeInsets.symmetric(horizontal: 16.0), double verticalOffset: 24.0, bool preferBelow: true, Widget child })

Creates a tooltip.

By default, tooltips prefer to appear below the child widget when the user long presses on the widget.

The message argument cannot be null.

Source 

Tooltip({
  Key key,
  this.message,
  this.height: 32.0,
  this.padding: const EdgeInsets.symmetric(horizontal: 16.0),
  this.verticalOffset: 24.0,
  this.preferBelow: true,
  this.child
}) : super(key: key) {
  assert(message != null);
  assert(height != null);
  assert(padding != null);
  assert(verticalOffset != null);
  assert(preferBelow != null);
  assert(child != null);
}