Dropdown.onValueChanged

描述

在用户单击了下拉列表中一个选项时调用的 UnityEvent。

可以用来检测用户选择下拉列表中的一个或多个选项的时间。添加一个监听器，当此 UnityEvent 检测到用户进行选择时执行操作。请参阅委托教程了解有关委托的更多信息。

//Create a new Dropdown GameObject by going to the Hierarchy and clicking Create>UI>Dropdown. Attach this script to the Dropdown GameObject.
//Set your own Text in the Inspector window

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;
    }
}