Unity 代码检测单击,双击,拖放

using UnityEngine;
using System.Collections;

public class Test2 : MonoBehaviour {

    public float oneTime;           //检测双击的有效时间
    private int downCount;          //判断是单击还是双击
    private bool currentCheck;      //当前正在检测
    private bool isTuoDong;         //是否拖动
    private bool startTuoDong;      //开始拖动
    void Update () {


        if(Input.GetKeyDown(KeyCode.A))
        {
            downCount++;
            isTuoDong = true;
            if (currentCheck == false) 
            {
                StartCoroutine(CheckDown());
            }
        }

        if (Input.GetKeyUp(KeyCode.A)) 
        {
            isTuoDong = false;
            startTuoDong = false;
        }

        if (startTuoDong) 
        {
            Debug.Log("正在拖动");   
        }
    }

    IEnumerator CheckDown() 
    {
        currentCheck = true;
        yield return new WaitForSeconds(oneTime);

        if (isTuoDong) 
        {
            Debug.Log("拖动");
            startTuoDong = true;

        }else if (downCount >= 2)         //说明是双击
        {
            Debug.Log("双击");
        }
        else if (downCount == 1)    //单击
        {
            Debug.Log("单击");
        }

        downCount = 0;
        currentCheck = false;

    }

}