Unity/UIDropdown

Dropdown追加方法

1. UI/Dropdownを追加
2. Dropdownを選択肢Inspectorのoptionsから選択項目を編集する

Dropdown選択値取得サンプル

using UnityEngine;
using UnityEngine.UI;
public class Example : MonoBehaviour
{
    Dropdown m_Dropdown;
    public Text m_Text;
    void Start()
    {
        //Fetch the Dropdown GameObject
        m_Dropdown = GetComponent<Dropdown>();
        //Add listener for when the value of the Dropdown changes, to take action
        m_Dropdown.onValueChanged.AddListener(delegate {
                DropdownValueChanged(m_Dropdown);
            });
        //Initialise the Text to say the first value of the Dropdown
        m_Text.text = "First Value : " + m_Dropdown.value;
    }
    //Ouput the new value of the Dropdown into Text
    void DropdownValueChanged(Dropdown change)
    {
        m_Text.text =  "New Value : " + change.value;
    }
}

参考：https://docs.unity3d.com/ja/current/ScriptReference/UI.Dropdown-onValueChanged.html

選択項目の高さが狭い場合

1. Dropdown/templates/scaleのyを1から3とかにする

選択項目の幅が狭い場合

1. Dropdown/templates/scaleのxを1から3とかにする
2. Dropdownの横幅が長くなるので、Dropdown/templatesのLeftとRightを200ぐらいにして狭くする

Dropdownの選択項目追加

using UnityEngine;
using UnityEngine.UI;
using System.Collections.Generic;
public class Example : MonoBehaviour
{
    //The list of messages for the Dropdown
    List<Dropdown.OptionData> m_Messages = new List<Dropdown.OptionData>();
    //This is the Dropdown
    Dropdown m_Dropdown;
    string m_MyString;
    int m_Index;
    void Start()
    {
        //Fetch the Dropdown GameObject the script is attached to
        m_Dropdown = GetComponent<Dropdown>();
        //Clear the old options of the Dropdown menu
        m_Dropdown.ClearOptions();

        List<string> names = new List<string> { "Option 1", "Option 2" };
        foreach (string name in names) {
            Dropdown.OptionData m_NewData = new Dropdown.OptionData();
            m_NewData.text = name;
            m_Messages.Add(m_NewData);
        }

        //Take each entry in the message List
        foreach (Dropdown.OptionData message in m_Messages)
        {
            //Add each entry to the Dropdown
            m_Dropdown.options.Add(message);
            //Make the index equal to the total number of entries
            m_Index = m_Messages.Count - 1;
        }
    }
}

参考：https://docs.unity3d.com/ja/current/ScriptReference/UI.Dropdown-options.html

ListデータをDropdownへ反映

List<string> cars = new List<string>();
string car = "police";
Dropdown carDropdown;
void Start()
{
    carDropdown = GameObject.Find("/Canvas/CarDropdown").GetComponent<Dropdown>();
    carDropdown.onValueChanged.AddListener(delegate {
       CarDropdownValueChanged(carDropdown);
    });
}
void InitDropdown()
{
    cars.Add("taxi");
    cars.Add("police");
    List<Dropdown.OptionData> optionMessages = new List<Dropdown.OptionData>();
    Dropdown optionDropdown = GameObject.Find("CarDropdown").GetComponent<Dropdown>();
    optionDropdown.ClearOptions();
    foreach (string car in cars)
    {
        Dropdown.OptionData optionData;
        optionData = new Dropdown.OptionData();
        optionData.text = car;
        optionMessages.Add(optionData);
    }
    foreach (Dropdown.OptionData message in optionMessages)
    {
        optionDropdown.options.Add(message);
    }
    optionDropdown.value = cars.IndexOf(car);
    GameObject.Find("CarDropdown/Label").GetComponent<Text>().text = cars[optionDropdown.value].ToString();
}

void CarDropdownValueChanged(Dropdown change)
{
   car = cars[change.value];
   GameObject.Find("CarDropdown/Label").GetComponent<Text>().text = cars[optionDropdown.value].ToString();
}

前回のドロップダウンの開いたときのスクロール位置を記憶

TMP_Dropdown optionDropdown = GameObject.Find("/Canvas/Dropdown").GetComponent<TMP_Dropdown>();
optionDropdown.onValueChanged.AddListener(delegate {
    Transform listTransform = optionDropdown.transform.Find("Dropdown List/Viewport/Content");
    if (listTransform != null)
    {
        RectTransform list = listTransform.GetComponent<RectTransform>();
        RectTransform template = optionDropdown.transform.Find("Template/Viewport/Content").GetComponent<RectTransform>();
        template.anchoredPosition = list.anchoredPosition;
        template.anchoredPosition3D = list.anchoredPosition3D;
    }
});

参考：https://www.create-forever.games/dropdown-pulldown-position-restore/

Dropdownをcsで開く

TMP_Dropdown dropdown;
dropdown.show();