public override Widget build(BuildContext context)
{
D.assert(WidgetsD.debugCheckHasDirectionality(context));
if (route.scrollController == null)
{
_MenuLimits menuLimits = route.getMenuLimits(buttonRect, constraints.maxHeight, selectedIndex ?? 0);
route.scrollController = new ScrollController(initialScrollOffset: menuLimits.scrollOffset ?? 0);
}
TextDirection textDirection = Directionality.of(context);
Widget menu = new _DropdownMenu <T>(
route: route,
padding: padding.resolve(textDirection),
buttonRect: buttonRect,
constraints: constraints,
dropdownColor: dropdownColor
);
if (theme != null)
{
menu = new Theme(data: theme, child: menu);
}
return(MediaQuery.removePadding(
context: context,
removeTop: true,
removeBottom: true,
removeLeft: true,
removeRight: true,
child: new Builder(
builder: (BuildContext _context) => {
return new CustomSingleChildLayout(
layoutDelegate: new _DropdownMenuRouteLayout <T>(
buttonRect: buttonRect,
route: route,
textDirection: textDirection
),
child: menu
);
}
)
));
}
public override Widget buildPage(BuildContext context, Animation <float> animation,
Animation <float> secondaryAnimation)
{
D.assert(WidgetsD.debugCheckHasDirectionality(context));
float screenHeight = MediaQuery.of(context).size.height;
float maxMenuHeight = screenHeight - 2.0f * DropdownConstants._kMenuItemHeight;
float buttonTop = this.buttonRect.top;
float buttonBottom = this.buttonRect.bottom;
float topLimit = Mathf.Min(DropdownConstants._kMenuItemHeight, buttonTop);
float bottomLimit = Mathf.Max(screenHeight - DropdownConstants._kMenuItemHeight, buttonBottom);
float?selectedItemOffset = this.selectedIndex * DropdownConstants._kMenuItemHeight +
Constants.kMaterialListPadding.top;
float?menuTop = (buttonTop - selectedItemOffset) -
(DropdownConstants._kMenuItemHeight - this.buttonRect.height) / 2.0f;
float preferredMenuHeight = (this.items.Count * DropdownConstants._kMenuItemHeight) +
Constants.kMaterialListPadding.vertical;
float menuHeight = Mathf.Min(maxMenuHeight, preferredMenuHeight);
float?menuBottom = menuTop + menuHeight;
if (menuTop < topLimit)
{
menuTop = Mathf.Min(buttonTop, topLimit);
}
if (menuBottom > bottomLimit)
{
menuBottom = Mathf.Max(buttonBottom, bottomLimit);
menuTop = menuBottom - menuHeight;
}
if (this.scrollController == null)
{
float scrollOffset = preferredMenuHeight > maxMenuHeight
? Mathf.Max(0.0f, selectedItemOffset ?? 0.0f - (buttonTop - (menuTop ?? 0.0f)))
: 0.0f;
this.scrollController = new ScrollController(initialScrollOffset: scrollOffset);
}
Widget menu = new _DropdownMenu <T>(
route: this,
padding: this.padding
);
if (this.theme != null)
{
menu = new Theme(data: this.theme, child: menu);
}
return(MediaQuery.removePadding(
context: context,
removeTop: true,
removeBottom: true,
removeLeft: true,
removeRight: true,
child: new Builder(
builder: (BuildContext _context) => {
return new CustomSingleChildLayout(
layoutDelegate: new _DropdownMenuRouteLayout <T>(
buttonRect: this.buttonRect,
menuTop: menuTop ?? 0.0f,
menuHeight: menuHeight
),
child: menu
);
}
)
));
}
