DebugWindow.cs

#if IS_DEBUG
using System;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

/// <summary>
/// uGUIを使ってウィンドウを表示するやつ
/// </summary>
public class DebugWindow : MonoBehaviour, IDisposable, IBeginDragHandler, IDragHandler
{
  Canvas _canvas;
  Sprite _whiteSprite;
  Font _font;
  RectTransform _rectTransform;

  Text _title;
  RectTransform _container;

  Vector2 _dragStartPosition;

  ScrollRect _scrollRect;
  VerticalLayoutGroup _scrollRectLayoutGroup;
  LayoutElement _scrollRectLayoutElement;
  RectTransform _viewportTransform;
  Mask _viewportMask;
  Image _viewportImage;
  VerticalLayoutGroup _viewportLayoutGroup;
  ContentSizeFitter _scrollRectSizeFitter;
  ContentSizeFitter _viewportSizeFitter;

  float? _fixedHeight;

  public string title { get => _title.text; set => gameObject.name = _title.text = value; }
  public float width { get => _rectTransform.sizeDelta.x; set => _rectTransform.sizeDelta = new Vector2(value, 0); }
  public Action onDestroy;

  /// <summary>
  /// <c>null</c>なら自動で調整して、<c>null</c>じゃない場合は指定した高さに固定する
  /// </summary>
  public float? fixedHeight {
    get => _fixedHeight;
    set {
      if ((_fixedHeight = value) is float v) {
        _scrollRect.enabled = true;
        _scrollRectLayoutGroup.enabled = false;
        _scrollRectSizeFitter.enabled = false;
        _scrollRectLayoutElement.enabled = true;
        _viewportMask.enabled = true;
        _viewportImage.enabled = true;
        _viewportLayoutGroup.enabled = false;
        _viewportSizeFitter.enabled = false;

        _viewportTransform.anchorMin = Vector2.zero;
        _viewportTransform.anchorMax = Vector2.one;
        _viewportTransform.offsetMin = _viewportTransform.offsetMax = Vector2.zero;
        _scrollRectLayoutElement.minHeight = v;
      }
      else {
        _scrollRect.enabled = false;
                  _scrollRectLayoutGroup.enabled = true;
        _scrollRectSizeFitter.enabled = true;
        _scrollRectLayoutElement.enabled = false;
        _viewportMask.enabled = false;
        _viewportImage.enabled = false;
                  _viewportLayoutGroup.enabled = true;
        _viewportSizeFitter.enabled = true;
      }
    }
  }

  public static DebugWindow Create(Canvas canvas, Sprite white, Font font, string title = null)
  {
    var gameObject = new GameObject(title ?? "DebugWindow");
    var c = gameObject.AddComponent<DebugWindow>();
    c.Setup(canvas, white, font);
    return c;
  }

  void Setup(Canvas canvas, Sprite white, Font font)
  {
    _canvas = canvas;
    _whiteSprite = white;
    _font = font;

    _rectTransform = gameObject.AddComponent<RectTransform>();
    _rectTransform.SetParent(canvas.transform, false);
    _rectTransform.pivot = _rectTransform.anchorMin = _rectTransform.anchorMax = Vector2.up;
    _rectTransform.anchoredPosition = Vector2.zero;
    // 高さは子の高さに勝手に合う
    _rectTransform.sizeDelta = new Vector2(300, 0);

    var background = gameObject.AddComponent<Image>();
    background.raycastTarget = true;
    background.sprite = _whiteSprite;
    background.color = new Color(1, 1, 1, 0.27f);

    var verticalLayout = gameObject.AddComponent<VerticalLayoutGroup>();
    verticalLayout.padding = new RectOffset(2, 2, 2, 2);
    verticalLayout.spacing = 2;
    verticalLayout.childControlWidth = true;
    verticalLayout.childControlHeight = true;
    verticalLayout.childScaleWidth = verticalLayout.childScaleHeight = false;
    verticalLayout.childForceExpandWidth = true;
    verticalLayout.childForceExpandHeight = false;

    var headerGameObject = new GameObject("Header");
    headerGameObject.transform.SetParent(verticalLayout.transform, false);
    var header = headerGameObject.AddComponent<HorizontalLayoutGroup>();
    // 幅は親に勝手に合う
    header.GetRectTransform().sizeDelta = new Vector2(0, 36);
    header.padding = new RectOffset(2, 2, 2, 2);
    header.spacing = 2;
    header.childControlWidth = header.childControlHeight = true;
    header.childScaleWidth = header.childScaleHeight = false;
    header.childForceExpandWidth = false;
    header.childForceExpandHeight = true;
    var headerImage = headerGameObject.AddComponent<Image>();
    headerImage.sprite = _whiteSprite;
    headerImage.color = new Color(0, 0, 0, 0.5f);
    headerGameObject.AddComponent<LayoutElement>().minHeight = 36;

    _title = CreateText("Title", gameObject.name);
    _title.gameObject.AddComponent<LayoutElement>().flexibleWidth = 1;
    _title.transform.SetParent(header.transform, false);

    var collapseButton = CreateButton("CollapseButton", "_");
    var collapseButtonLayoutElement = collapseButton.gameObject.AddComponent<LayoutElement>();
    collapseButtonLayoutElement.preferredWidth = collapseButtonLayoutElement.minWidth = 32;
    collapseButtonLayoutElement.flexibleWidth = 0;
    collapseButton.GetRectTransform().sizeDelta = new Vector2(32, 32);
    collapseButton.transform.SetParent(header.transform, false);

    var closeButton = Instantiate(collapseButton, header.transform);
    closeButton.gameObject.name = "CloseButton";
    closeButton.transform.GetChild(0).GetComponent<Text>().text = "×";

    var sizeFitter = gameObject.AddComponent<ContentSizeFitter>();
    sizeFitter.horizontalFit = ContentSizeFitter.FitMode.Unconstrained;
    sizeFitter.verticalFit = ContentSizeFitter.FitMode.PreferredSize;

    var scrollRect = new GameObject("ScrollRect");
    var scrollRectTransform = scrollRect.AddComponent<RectTransform>();
    scrollRectTransform.SetParent(_rectTransform);
    _scrollRect = scrollRect.AddComponent<ScrollRect>();
    _scrollRect.horizontal = false;
    _scrollRectLayoutGroup = scrollRect.AddComponent<VerticalLayoutGroup>();
    _scrollRectSizeFitter = scrollRect.AddComponent<ContentSizeFitter>();
    _scrollRectSizeFitter.verticalFit = ContentSizeFitter.FitMode.PreferredSize;
    _scrollRectLayoutElement = scrollRect.AddComponent<LayoutElement>();

    var viewport = new GameObject("Viewport");
    _viewportTransform = viewport.AddComponent<RectTransform>();
    _viewportTransform.SetParent(scrollRectTransform);
    _viewportLayoutGroup = viewport.AddComponent<VerticalLayoutGroup>();
    _viewportLayoutGroup.childControlHeight = false;
    _viewportSizeFitter = viewport.AddComponent<ContentSizeFitter>();
    _viewportSizeFitter.verticalFit = ContentSizeFitter.FitMode.PreferredSize;
    _viewportMask = viewport.AddComponent<Mask>();
    _viewportMask.showMaskGraphic = false;
    _viewportImage = viewport.AddComponent<Image>();
    _viewportImage.sprite = _whiteSprite;

    var container = new GameObject("Container");
    _container = container.AddComponent<RectTransform>();
    _container.SetParent(_viewportTransform, false);
    _container.pivot = Vector2.one;
    var containerVerticalLayout = container.AddComponent<VerticalLayoutGroup>();
    containerVerticalLayout.padding = new RectOffset(2, 2, 2, 2);
    containerVerticalLayout.spacing = 0;
    containerVerticalLayout.childControlWidth = true;
    containerVerticalLayout.childControlHeight = false;
    containerVerticalLayout.childScaleWidth = containerVerticalLayout.childScaleHeight = false;
    containerVerticalLayout.childForceExpandWidth = true;
    containerVerticalLayout.childForceExpandHeight = false;
    var containerSizeFitter = container.AddComponent<ContentSizeFitter>();
    containerSizeFitter.horizontalFit = ContentSizeFitter.FitMode.Unconstrained;
    containerSizeFitter.verticalFit = ContentSizeFitter.FitMode.PreferredSize;
    var containerImage = container.AddComponent<Image>();
    containerImage.sprite = _whiteSprite;
    containerImage.color = new Color(0, 0, 0, 0.5f);

    _scrollRect.content = _container;
    _scrollRect.viewport = _viewportTransform;

    collapseButton.onClick.AddListener(() => scrollRect.SetActive(!scrollRect.activeSelf));
    closeButton.onClick.AddListener(Destroy);

    fixedHeight = null;
  }

  public void Dispose()
  {
    _canvas = null;
    _whiteSprite = null;
    _font = null;
    _rectTransform = null;

    _title = null;
    _container = null;

    _scrollRect = null;
    _scrollRectLayoutGroup = null;
    _scrollRectSizeFitter = null;
    _scrollRectLayoutElement = null;
    _viewportTransform = null;
    _viewportMask = null;
    _viewportImage = null;
    _viewportLayoutGroup = null;
    _viewportSizeFitter = null;
  }

  public void OnBeginDrag(PointerEventData eventData)
  {
    _dragStartPosition = _rectTransform.anchoredPosition;
  }

  public void OnDrag(PointerEventData eventData)
  {
    _rectTransform.anchoredPosition = _dragStartPosition + (eventData.position - eventData.pressPosition) / _canvas.scaleFactor;
  }

  public void Destroy()
  {
    Destroy(gameObject);
  }

  void OnDestroy()
  {
    onDestroy?.Invoke();
    Dispose();
  }

  public void Clear()
  {
    foreach (Transform element in _container) {
      Destroy(element.gameObject);
    }
    Canvas.ForceUpdateCanvases();
  }

  public void Remove(GameObject element)
  {
    Destroy(element);
    Canvas.ForceUpdateCanvases();
  }

  public void AddSpacer(float height)
  {
    var gameObject = new GameObject("Spacer");
    gameObject.GetRectTransform().sizeDelta = new Vector2(0, height);
    gameObject.transform.SetParent(_container, false);
  }

  public Button AddButton(string text, Action onClick = null)
  {
    var button = CreateButton("Button", text);
    button.transform.SetParent(_container, false);
    if (onClick != null) {
      button.onClick.AddListener(() => onClick());
    }
    Canvas.ForceUpdateCanvases();
    return button;
  }

  public Text AddText(string value)
  {
    var text = CreateText("Text", value);
    var rectTransform = text.rectTransform;
    rectTransform.SetParent(_container, false);
    rectTransform.sizeDelta = new Vector2(0, 32);
    Canvas.ForceUpdateCanvases();
    return text;
  }

  public Slider AddSlider(int min, int max, Action<int> onChange = null)
  {
    var slider = CreateSlider();
    slider.wholeNumbers = true;
    slider.minValue = min;
    slider.maxValue = max;
    slider.transform.SetParent(_container, false);
    if (onChange != null) {
      slider.onValueChanged.AddListener(v => onChange((int)v));
    }
    Canvas.ForceUpdateCanvases();
    return slider;
  }

  public Slider AddSlider(float min, float max, Action<float> onChange = null)
  {
    var slider = CreateSlider();
    slider.minValue = min;
    slider.maxValue = max;
    slider.transform.SetParent(_container, false);
    if (onChange != null) {
      slider.onValueChanged.AddListener(v => onChange(v));
    }
    Canvas.ForceUpdateCanvases();
    return slider;
  }

  public Toggle AddToggle(string label, Action<bool> onChange = null)
  {
    var toggle = CreateToggle(label);
    toggle.transform.SetParent(_container, false);
    if (onChange != null) {
      toggle.onValueChanged.AddListener(v => onChange(v));
    }
    Canvas.ForceUpdateCanvases();
    return toggle;
  }

  public InputField AddInputField(string value = null, string placeholder = null, Action<string> onEndEdit = null)
  {
    var inputField = CreateInputField(placeholder);
    inputField.transform.SetParent(_container, false);
    if (!string.IsNullOrEmpty(value)) {
      inputField.text = value;
    }
    if (onEndEdit != null) {
      inputField.onEndEdit.AddListener(v => onEndEdit(v));
    }
    Canvas.ForceUpdateCanvases();
    return inputField;
  }

  public Dropdown AddDropdown(Action<string> onChange = null)
  {
    var dropdown = CreateDropdown();
    dropdown.transform.SetParent(_container, false);
    if (onChange != null) {
      dropdown.onValueChanged.AddListener(i => {
        onChange(dropdown.options[i].text);
      });
    }
    Canvas.ForceUpdateCanvases();
    return dropdown;
  }

  Text CreateText(string name, string value)
  {
    var textGameObject = new GameObject(name);
    var text = textGameObject.AddComponent<Text>();
    text.text = value;
    text.font = _font;
    text.fontSize = 24;
    text.lineSpacing = 0.5f;
    text.alignment = TextAnchor.MiddleLeft;
    text.color = Color.white;
    text.resizeTextMaxSize = 24;
    text.resizeTextForBestFit = true;
    textGameObject.AddComponent<LayoutElement>();
    return text;
  }

  Button CreateButton(string name, string label)
  {
    var buttonGameObject = new GameObject(name);
    var image = buttonGameObject.AddComponent<Image>();
    image.sprite = _whiteSprite;
    var button = buttonGameObject.AddComponent<Button>();
    buttonGameObject.GetRectTransform().sizeDelta = new Vector2(0, 32);
    var text = CreateText("Text", label);
    text.color = Color.black;
    text.alignment = TextAnchor.MiddleCenter;
    var textTransform = text.rectTransform;
    textTransform.SetParent(buttonGameObject.transform, false);
    textTransform.offsetMin = textTransform.offsetMax = Vector2.zero;
    textTransform.pivot = textTransform.anchorMin = Vector2.zero;
    textTransform.anchorMax = Vector2.one;
    buttonGameObject.AddComponent<LayoutElement>();
    return button;
  }

  Slider CreateSlider()
  {
    var sliderRoot = new GameObject("Slider");
    var slider = sliderRoot.AddComponent<Slider>();
    var sliderTransform = sliderRoot.GetRectTransform();
    sliderRoot.AddComponent<LayoutElement>();
    sliderTransform.sizeDelta = new Vector2(0, 20);

    var background = new GameObject("Background");
    var backgroundTransform = background.GetRectTransform();
    backgroundTransform.anchorMin = new Vector2(0, 0.25f);
    backgroundTransform.anchorMax = new Vector2(1, 0.75f);
    background.transform.SetParent(sliderTransform, false);
    var backgroundImage = background.AddComponent<Image>();
    backgroundImage.sprite = _whiteSprite;
    backgroundImage.type = Image.Type.Sliced;
    backgroundTransform.offsetMin = backgroundTransform.offsetMax = Vector2.zero;

    var fillArea = new GameObject("FillArea");
    var fillAreaTransform = fillArea.GetRectTransform();
    fillAreaTransform.SetParent(sliderTransform, false);
    fillAreaTransform.anchorMin = new Vector2(0, 0.25f);
    fillAreaTransform.anchorMax = new Vector2(1, 0.75f);
    fillAreaTransform.offsetMin = new Vector2(5, 0);
    fillAreaTransform.offsetMax = new Vector2(-15, 0);

    var fill = new GameObject("Fill");
    var fillTransform = fill.GetRectTransform();
    fillTransform.SetParent(fillAreaTransform, false);
    fillTransform.offsetMin = new Vector2(-5, 0);
    fillTransform.offsetMax = new Vector2(15, 0);
    var fillImage = fill.AddComponent<Image>();
    fillImage.sprite = _whiteSprite;
    fillImage.type = Image.Type.Sliced;

    var slideArea = new GameObject("Handle Slide Area");
    var slideAreaTransform = slideArea.GetRectTransform();
    slideAreaTransform.SetParent(sliderTransform, false);
    slideAreaTransform.anchorMin = Vector2.zero;
    slideAreaTransform.anchorMax = Vector2.one;
    slideAreaTransform.offsetMin = new Vector2(10, 0);
    slideAreaTransform.offsetMax = new Vector2(-10, 0);

    var handle = new GameObject("Handle");
    var handleTransform = handle.GetRectTransform();
    handleTransform.SetParent(slideAreaTransform, false);
    handleTransform.offsetMin = handleTransform.offsetMax = Vector2.zero;
    handleTransform.sizeDelta = new Vector2(20, 0);
    var handleImage = handle.AddComponent<Image>();
    handleImage.sprite = _whiteSprite;

    slider.targetGraphic = handleImage;
    slider.fillRect = fillTransform;
    slider.handleRect = handleTransform;

    return slider;
  }

  Toggle CreateToggle(string label)
  {
    var toggleRoot = new GameObject("Toggle");
    var toggle = toggleRoot.AddComponent<Toggle>();
    var toggleTransform = toggle.GetRectTransform();
    toggleTransform.sizeDelta = new Vector2(0, 32);

    var background = new GameObject("Background");
    var backgroundImage = background.AddComponent<Image>();
    backgroundImage.sprite = _whiteSprite;
    var backgroundTransform = backgroundImage.rectTransform;
    backgroundTransform.SetParent(toggleTransform, false);
    backgroundTransform.anchorMin = backgroundTransform.anchorMax = Vector2.up;
    backgroundTransform.sizeDelta = new Vector2(24, 24);
    backgroundTransform.anchoredPosition = new Vector2(12, -16);

    var checkmark = CreateText("Checkmark", "✓");
    checkmark.fontSize = 18;
    checkmark.alignment = TextAnchor.MiddleCenter;
    checkmark.color = Color.black;
    checkmark.resizeTextForBestFit = false;
    var checkmarkTransform = checkmark.rectTransform;
    checkmarkTransform.SetParent(backgroundTransform, false);
    checkmarkTransform.anchorMin = Vector2.zero;
    checkmarkTransform.anchorMax = Vector2.one;
    checkmarkTransform.offsetMin = Vector2.zero;
    checkmarkTransform.offsetMax = Vector2.zero;

    var text = CreateText("Text", label);
    var textTransform = text.rectTransform;
    textTransform.SetParent(toggleTransform, false);
    textTransform.anchorMin = Vector2.zero;
    textTransform.anchorMax = Vector2.one;
    textTransform.offsetMin = new Vector2(25, 0);
    textTransform.offsetMax = Vector2.zero;

    toggle.targetGraphic = backgroundImage;
    toggle.graphic = checkmark;

    return toggle;
  }

  InputField CreateInputField(string placeholderText)
  {
    var root = new GameObject("InputField");
    var rootImage = root.AddComponent<Image>();
    rootImage.sprite = _whiteSprite;
    rootImage.rectTransform.sizeDelta = new Vector2(0, 40);
    var inputField = root.AddComponent<InputField>();
    inputField.targetGraphic = rootImage;
    var rootTransform = root.transform;

    var placeholder = CreateText("Placeholder", "");
    placeholder.fontSize = 24;
    placeholder.color = Color.gray;
    placeholder.text = placeholderText;
    placeholder.horizontalOverflow = HorizontalWrapMode.Wrap;
    var placeholderTransform = placeholder.rectTransform;
    placeholderTransform.SetParent(rootTransform, false);
    placeholderTransform.anchorMin = Vector2.zero;
    placeholderTransform.anchorMax = Vector2.one;
    placeholderTransform.offsetMin = new Vector2(5, 0);
    placeholderTransform.offsetMax = new Vector2(-5, 0);
    inputField.placeholder = placeholder;

    var text = CreateText("Text", "");
    text.fontSize = 24;
    text.color = Color.black;
    var textTransform = text.rectTransform;
    textTransform.SetParent(rootTransform, false);
    textTransform.anchorMin = Vector2.zero;
    textTransform.anchorMax = Vector2.one;
    textTransform.offsetMin = new Vector2(5, 0);
    textTransform.offsetMax = new Vector2(-5, 0);
    inputField.textComponent = text;
    text.horizontalOverflow = HorizontalWrapMode.Wrap;
    return inputField;
  }

  Dropdown CreateDropdown()
  {
    var templateGameObject = new GameObject("Template");
    var template = templateGameObject.AddComponent<RectTransform>();
    var scrollRect = templateGameObject.AddComponent<ScrollRect>();
    templateGameObject.AddComponent<Canvas>();
    templateGameObject.AddComponent<GraphicRaycaster>();
    templateGameObject.AddComponent<CanvasGroup>();
    template.anchorMin = Vector2.zero;
    template.anchorMax = Vector2.right;
    template.pivot = new Vector2(0.5f, 1);
    template.Translate(0, -50, 0);

    var viewport = new GameObject("Viewport");
    var viewportTransform = viewport.AddComponent<RectTransform>();
    var viewportImage = viewport.AddComponent<Image>();
    viewportImage.sprite = _whiteSprite;
    viewportImage.color = new Color(0.93f, 0.93f, 0.93f);
    viewport.AddComponent<Mask>();
    viewportTransform.anchorMin = Vector2.zero;
    viewportTransform.anchorMax = Vector2.one;
    viewportTransform.pivot = Vector2.up;
    viewportTransform.offsetMax = new Vector2(0, 0);
    viewportTransform.SetParent(template, false);

    scrollRect.viewport = viewportTransform;

    var content = new GameObject("Content");
    var contentTransform = content.AddComponent<RectTransform>();
    contentTransform.sizeDelta = new Vector2(0, 28);
    contentTransform.anchorMin = Vector2.up;
    contentTransform.anchorMax = Vector2.one;
    contentTransform.pivot = new Vector2(0.5f, 1);
    contentTransform.SetParent(viewportTransform, false);

    scrollRect.content = contentTransform;

    var itemGameObject = new GameObject("Item");
    var itemTransform = itemGameObject.AddComponent<RectTransform>();
    var itemToggle = itemGameObject.AddComponent<Toggle>();
    itemTransform.sizeDelta = new Vector2(0, 35);
    itemTransform.anchorMin = new Vector2(0, 0.5f);
    itemTransform.anchorMax = new Vector2(1, 0.5f);
    itemTransform.pivot = new Vector2(0.5f, 0.5f);
    itemTransform.SetParent(contentTransform, false);
    var itemToggleColors = itemToggle.colors;
    itemToggleColors.normalColor = new Color(0.93f, 0.93f, 0.93f);
    itemToggle.colors = itemToggleColors;

    var itemBackgroundGameObject = new GameObject("ItemBackground");
    var itemBackgroundTransform = itemBackgroundGameObject.AddComponent<RectTransform>();
    var itemBackground = itemBackgroundGameObject.AddComponent<Image>();
    itemBackgroundTransform.anchorMin = Vector2.zero;
    itemBackgroundTransform.anchorMax = Vector2.one;
    itemBackgroundTransform.offsetMin = Vector2.zero;
    itemBackgroundTransform.offsetMax = Vector2.zero;
    itemBackgroundTransform.SetParent(itemTransform, false);
    itemBackground.sprite = _whiteSprite;
    itemToggle.targetGraphic = itemBackground;

    var itemCheckmark = new GameObject("ItemCheckmark");
    var itemCheckmarkTransform = itemCheckmark.AddComponent<RectTransform>();
    itemCheckmarkTransform.sizeDelta = new Vector2(25, 25);
    itemCheckmarkTransform.anchorMin = new Vector2(0, 0.5f);
    itemCheckmarkTransform.anchorMax = new Vector2(0, 0.5f);
    itemCheckmarkTransform.pivot = new Vector2(0.5f, 0.5f);
    itemCheckmarkTransform.anchoredPosition = new Vector2(15, 0);
    itemCheckmarkTransform.SetParent(itemTransform, false);
    var itemCheckmarkText = itemCheckmark.AddComponent<Text>();
    itemCheckmarkText.alignment = TextAnchor.MiddleCenter;
    itemCheckmarkText.font = _font;
    itemCheckmarkText.fontSize = 24;
    itemCheckmarkText.color = Color.black;
    itemCheckmarkText.text = "✓";
    itemToggle.graphic = itemCheckmarkText;

    var itemLabel = new GameObject("ItemLabel");
    var itemLabelTransform = itemLabel.AddComponent<RectTransform>();
    itemLabelTransform.anchorMin = Vector2.zero;
    itemLabelTransform.anchorMax = Vector2.one;
    itemLabelTransform.pivot = new Vector2(0.5f, 0.5f);
    itemLabelTransform.offsetMin = new Vector2(35, 2);
    itemLabelTransform.offsetMax = new Vector2(-10, -1);
    itemLabelTransform.SetParent(itemTransform, false);
    var itemLabelText = itemLabel.AddComponent<Text>();
    itemLabelText.alignment = TextAnchor.MiddleLeft;
    itemLabelText.font = _font;
    itemLabelText.fontSize = 24;
    itemLabelText.color = Color.black;

    var root = new GameObject("Dropdown");
    var dropdown = root.AddComponent<Dropdown>();
    var image = root.AddComponent<Image>();
    image.sprite = _whiteSprite;

    var text = CreateText("Text", "");
    text.fontSize = 24;
    text.color = Color.black;
    text.alignment = TextAnchor.MiddleLeft;
    var textTransform = text.rectTransform;
    textTransform.anchorMin = Vector2.zero;
    textTransform.anchorMax = Vector2.one;
    textTransform.offsetMin = Vector2.zero;
    textTransform.offsetMax = Vector2.zero;
    textTransform.SetParent(dropdown.transform, false);

    var arrow = CreateText("Arrow", "▾");
    arrow.fontSize = 24;
    arrow.color = Color.black;
    arrow.alignment = TextAnchor.MiddleCenter;
    var arrowTransform = arrow.rectTransform;
    arrowTransform.anchorMin = new Vector2(1, 0.5f);
    arrowTransform.anchorMax = new Vector2(1, 0.5f);
    arrowTransform.pivot = new Vector2(1f, 0.5f);
    arrowTransform.anchoredPosition = Vector2.zero;
    arrowTransform.sizeDelta = new Vector2(24, 24);
    arrowTransform.SetParent(dropdown.transform, false);

    template.SetParent(dropdown.transform);
    template.gameObject.SetActive(false);

    dropdown.GetRectTransform().sizeDelta = new Vector2(0, 30);
    dropdown.targetGraphic = image;
    dropdown.itemText = itemLabelText;
    dropdown.template = template;
    dropdown.captionText = text;

    return dropdown;
  }
}
#endif