void _handleTap()
{
RenderBox itemBox = (RenderBox)this.context.findRenderObject();
Rect itemRect = itemBox.localToGlobal(Offset.zero) & itemBox.size;
EdgeInsets menuMargin = ButtonTheme.of(this.context).alignedDropdown
? DropdownConstants._kAlignedMenuMargin
: DropdownConstants._kUnalignedMenuMargin;
D.assert(this._dropdownRoute == null);
this._dropdownRoute = new _DropdownRoute <T>(
items: this.widget.items,
buttonRect: menuMargin.inflateRect(itemRect),
padding: DropdownConstants._kMenuItemPadding,
selectedIndex: this._selectedIndex ?? 0,
elevation: this.widget.elevation,
theme: Theme.of(this.context, shadowThemeOnly: true),
style: this._textStyle,
barrierLabel: MaterialLocalizations.of(this.context).modalBarrierDismissLabel
);
Navigator.push(this.context, this._dropdownRoute).Then(newValue => {
_DropdownRouteResult <T> value = newValue as _DropdownRouteResult <T>;
this._dropdownRoute = null;
if (!this.mounted || newValue == null)
{
return;
}
if (this.widget.onChanged != null)
{
this.widget.onChanged(value.result);
}
});
}