Touch.phase

Description

描述触摸阶段。

触摸 phase 指手指在最近的帧更新时采取的操作。因为设备在整个“生命周期”中对触摸进行跟踪，所以触摸的开始和结束以及之间的移动可以在发生触摸的帧上报告。phase 属性可以用作 switch 语句的基础或用作更复杂的状态处理系统的一部分。

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    public Vector2 startPos;
    public Vector2 direction;
    public bool directionChosen;
    void Update()
    {
        // Track a single touch as a direction control.
        if (Input.touchCount > 0)
        {
            Touch touch = Input.GetTouch(0);

            // Handle finger movements based on touch phase.
            switch (touch.phase)
            {
                // Record initial touch position.
                case TouchPhase.Began:
                    startPos = touch.position;
                    directionChosen = false;
                    break;

                // Determine direction by comparing the current touch position with the initial one.
                case TouchPhase.Moved:
                    direction = touch.position - startPos;
                    break;

                // Report that a direction has been chosen when the finger is lifted.
                case TouchPhase.Ended:
                    directionChosen = true;
                    break;
            }
        }
        if (directionChosen)
        {
            // Something that uses the chosen direction...
        }
    }
}