How to resize VBoxContainer to make its height less than the children needed

[shimizuthelotus]

Godot Version

Godot4.4

Question

How to resize VBoxContainer to make its height less than the children needed?

I’m making a new Control called Expandable, it was designed with these features:

• Expand and shrink animation
• Show and hide Children

The structure of the control is

• Expandable (PanelContainer)
  • UIContainer (VBoxContainer)
    • UIHeader (Clickable) (Just like a button)

The children will be added into UIContainer, and when the control shrinks, I expected the control will shrink and only UIHeader will be shown. But after I clicked UIHeader, all the children are still shown, only the height more than the children needed are removed, all the childrens are still shown. How can I force the control to shrink ignoring the height the children needs? (Please don’t resize the children)

Here’s my source code, and I think the problem happens in ToggleExpand(). Thanks!

using Godot;
using System;

public partial class ExpandableLite : Node
{
    [Export]
    public VBoxContainer UIContainer;
    [Export]
    public Clickable UIHeader;

    public bool IsExpand = true;
    public Tween _tween;

    public override void _Ready()
    {
        UIHeader.Clicked += UIHeader_Clicked;
    }

    private void UIHeader_Clicked()
    {
        IsExpand = !IsExpand;
        ToggleExpand();
    }

    public void ToggleExpand()
    {
        if (_tween != null)
        {
            _tween.Kill();
        }
        float targetHeight = UIHeader.Size.Y;
        if (IsExpand)
        {
            targetHeight += GetChildPanelTargetHeight();
        }
        _tween = CreateTween()
            .SetEase(Tween.EaseType.Out)
            .SetTrans(Tween.TransitionType.Circ);

        _tween.TweenProperty(this, "size", new Vector2(UIContainer.Size.X, targetHeight), 0.35);
    }

    private float GetChildPanelTargetHeight()
    {
        float totalHeight = 0f;

        var container = UIContainer as Container;
        var padding = container?.GetThemeConstant("margin_top") ?? 0f
                    + container?.GetThemeConstant("margin_bottom") ?? 0f;

        foreach (Node child in UIContainer.GetChildren())
        {
            if (child is Control control && control.Visible)
            {
                totalHeight += control.Size.Y;

                if (UIContainer is VBoxContainer vbox)
                {
                    totalHeight += vbox.GetThemeConstant("separation");
                }
            }
        }
        return totalHeight + padding;
    }
}

[zdrmlpzdrmlp]

@shimizuthelotus

How can I force the control to shrink ignoring the height the children needs? (Please don’t resize the children)

@shimizuthelotus

Expandable (PanelContainer)

• UIContainer (VBoxContainer)
  • UIHeader (Clickable) (Just like a button)

Try use scroll container as the parent of the UIContainer. The PanelContainer mostly used to contain and follow what the child sizes are.

[shimizuthelotus]

Thanks! It works, but another problem occurred. When Expandable is shrinked, if the mouse wheel scrolls, it will scroll. If I set Vertical scroll mode to Disabled, The panel will not able to keep its size. Is it possible to solve that?

Expand:

Shrink:

Shrink, and scroll:

[shimizuthelotus]

Okay it’s all solved, Thanks!

I added this code on scroll container

using Godot;
using System;

public partial class LockScrollContainer : ScrollContainer
{
    public bool AllowScrolling = false;

    public override void _GuiInput(InputEvent @event)
    {
        if (@event is InputEventMouseButton mouseEvent &&
            (mouseEvent.ButtonIndex == MouseButton.WheelUp ||
             mouseEvent.ButtonIndex == MouseButton.WheelDown))
        {
            if (!AllowScrolling)
            {
                AcceptEvent();
            }
        }

        if (@event is InputEventPanGesture panGesture)
        {
            if (!AllowScrolling)
            {
                AcceptEvent();
            }
        }

        base._GuiInput(@event);
    }
}