Debugging Urho GUI

Hi, all!

As I told a lot lately I have showstopper kind of trouble with UI elements which generate popup window.
These are Menu and DropDownList. Both do display original widget but fail to display popup menu.
Today I was able to display Menu popup for some time but after some minimal change it stopped working again
and then I was not able to repeat the result. Struggling for 20+ hours for nothing again, I decided to
debug the thing properly, so to find out why it is so brittle. Could somebody point me out somewhere in Urho code
so I look for the culprits?
Please don’t point me to editor, I know everything works there, but it is not possible to repeat.
Probably there are some not obvious magic happens.
I found that popup window defaultStyle needs to be set to style XML otherwise it will display
white (root window style do not apply), but that happened before. Now I see nothing at all,
like nothing is drawn and the click is ignored. I tried to display popup window manually and it works fine,
so it is something with menu itself which is wrong. I will probably replace it with separate button and menu
if debugging will take too long, but I’d prefer to finally make such widgets work and solve this puzzle…

Can’t offer advice on debugging the GUI, but here’s the code I use to make a dropdown list for a simple in-game editor I have (if you need any more of the code let me know, I tried to just pull out whatever was needed for the DropDownList):

SharedPtr<UIElement> me_;
	static SharedPtr<XMLFile> Style;

void EditorGroup::SetPosition(UIElement* child)
	if (!child)
	IntVector2 size = child->GetMinSize();
	if (useColumns_)
		position_.y_ += size.y_;
		breakOffset_ = Max(size.x_, breakOffset_);
		me_->SetMinSize(position_.x_ + breakOffset_, position_.y_);
		position_.x_ += size.x_;
		breakOffset_ = Max(size.y_, breakOffset_);
		me_->SetMinSize(position_.x_, position_.y_ + breakOffset_);

EditorGroup* EditorGroup::CreateDropdown(String label, Vector<Variant> values, int val)

	DropDownList* l = me_->CreateChild<DropDownList>(label);
	int height = 0; int width = 0;
	for (int i = 0; i < values.Size(); ++i)
		width = Max(width, 8*values[i].GetString().Length());
		height = Max(height, 16);
	EditorGroup* c = new EditorGroup(l);
	l->SetMinSize(width, height);

	for (int i = 0; i < values.Size(); ++i)
		Text* item = new Text(l->GetContext());

	c->type_ = DROPDOWN;
	c->defaultValue_ = val;
	c->extendedValue_ = values;
	c->SubscribeToEvent(l, E_ITEMSELECTED, HANDLER(EditorGroup, HandleEvent));
	return c;

Well, debugging the GUI I found that in both cases I have zero-sized window.
While I set window min sizes, it looks like it was resized to zero so not displaying.
Need to check this some meore…

I’m unable to reproduce Your problems. Can You show problematic parts of Your code or at least describe layout setup (parent-child structure, aligment etc.)?

You can also check this functions (ie copy and run in hello gui sample), both are working:

void CreateDropDown()
    DropDownList@ dropDown = ui.root.CreateChild("DropDownList", "List");
    dropDown.SetSize(128, 64);
    dropDown.SetPosition((graphics.width / 6), (graphics.height / 2));
    dropDown.resizePopup = true;
    for(int i = 0; i < 5; i++)
        Text@ item = Text();
        item.text = "Item" + String(i);

void CreatePopupMenu()
    Menu@ menu = ui.root.CreateChild("Menu", "menu");
    menu.SetPosition((graphics.width * 0.7), (graphics.height /2));
    Window@ popup = Window();
    popup.SetStyle("Window", cache.GetResource("XMLFile", "UI/DefaultStyle.xml"));
    menu.popup = popup;
    Text@ label = popup.CreateChild("Text", "label");
    label.text = "Popup Menu";
    label.textAlignment = HA_CENTER;
    label.enableAnchor = true;
    label.SetMinAnchor(0, 0);
    label.SetMaxAnchor(1, 0.15);
    label.SetPivot(0.0, 0.0);
    UIElement@ btnHolder = popup.CreateChild("UIElement", "btnHolder");
    btnHolder.enableAnchor = true;
    btnHolder.SetMinAnchor(0, 0.15);
    btnHolder.SetMaxAnchor(1, 1);
    btnHolder.SetLayout(LM_VERTICAL, 0, IntRect(0, 0, 0, 0));
    for(int i = 0; i < 3; i++)
        Button@ btn = btnHolder.CreateChild("Button", "btn");

I’m still in process of debugging. Somehow popup window size is set to 0, I currently debug why this happens.

I don’t want to repeat some magic passes, I want to understand what is really needed.

OK I now found the solution to my problem.

  1. Thou shalt set default style (defaultStyle) for all popup windows.
  2. Thou shalt SetLayout(LM_VERTICAL/LM_HRIZONTAL) on popup window.
    if LM_FREE is wanted add additional UIElement.
  3. ThouShalt SetMinSize after SetLayout.

I’m not sure about 3. but that fixed my problem. Then I removed it and there is no problem.
To be safe I set it back. It looks like it depends on what widgets are in the window.
I have Window->ScrollView->UIElement->{Lots of UIElement->{Checkbox, Text}}
When I did not have ScrollView it worked with 1 + 2, but as I added ScrollView it broke.
While fixing this I also did lots of reordering of operations, so the fix might be reordering + SetMinSize.
I don’t know but it works now. I will leave debugging code in there just in case it will break again.

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