GUI pull-down menu of unity3d evil door implementation dropdown design has no duplicate items

** Unity3D The evil door implementation series provides some requirements for bloggers in the actual development process , Because the personal level can not be realized in a serious way, it is adopted “ evil ways ” Achieve the same effect .**
This series is only for sharing ideas , If there is an error or “ carry coals to newcastle ” The place of , Please correct me a lot .

【 summary 】

Using the combination of buttons and pull-down menus , Click the button to display the drop-down menu , Realize menu control without duplicate items .

【 Specific process 】

U3D Use dropdown Make menu effect , There will be the problem of duplicate menu titles and items . Even if you change label, It will also change to the default first option at run time .

Bloggers have checked many articles , The main thing is to play tricks on the menu style , There is no mention of this repeated problem . Therefore, it is decided to adopt the form of cooperation with the button control , Separate menu titles from options , Just a few easy steps , You can change the method “ eliminate ” Duplicate item .

1. Create... In the project canvas canvas , stay canvas Create empty menu objects in for easy management , Then select Create in the menu object UI–button and UI–dropdown, Write on demand dropdown Of options. hide dropdown Of label and arrow.

2. take dropdown Control to button Upper and button coincidence , modify button The text of the control is “ menu ”. If menu design has color , Notice that the color of the button changes to transparent , Integrate with the environment . stay button Add a mouse click event to the properties , take dropdwon Select as the control object ,Runtime only The next choice dropdown–show(). Click the button to display the menu items .

3. Next, you can use the normal binding script to dropdown Options for event listening and response . Create a Script Folders are used to manage scripts , And create... In the folder menu Script . And in menu Edit the following code in the script （case The following can be replaced by the corresponding reaction event ）：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class Menu : MonoBehaviour
{
    // Implement multiple menu monitoring 
    public List<Dropdown> DropdownList;

    public void EventListening()
    {
        switch (DropdownList[0].value)
        {
            case 0:
                Debug.Log(" The kung pao chicken is ready ");
                break;
            case 1:
                Debug.Log(" Mapo Tofu is ready ");
                break;
            case 2:
                Debug.Log(" Fish flavored shredded pork is ready ");
                break;
            case 3:
                Debug.Log(" Boiled meat slices are ready ");
                break;
            default:
                break;
        }
    }
}

4. Click on the menu object , Create an empty object , Name it MenuControl, And drag the script you just created into the object .

The variables defined in the script will be displayed after dragging the script ,List Is the number of menus , Free to set . I'm going to set it to 1, And put the elements 0 Set to the menu just created _dropdown. This step is mainly used to expand menu management in the future .

5. Select menu _dropdown, Click on the bottom when the value changes + Number , take MenuControl Select as the control object （ Or drag it directly ）,Runtime Only Side selection Menu–Eventlistening, The response event of the drop-down menu option can be realized .（ Multiple menus are in Menu Create the corresponding... In the script listening function ）

【 Realization effect 】

【 Source code Demo】

Unity Editor version ：2019.4.35
https://download.csdn.net/download/mudapao/85651230