在Unity中无需抬起手指即可检测滑动[重复]

Question

我正在实现特定类型的触摸控制器。 玩家需要将手指放在屏幕上才能移动。 在不抬起手指的情况下，玩家可以在移动的同时向不同方向滑动以改变方向。 一旦手指抬起，播放器就会停止移动。

很难隔离特定的滑动（即在屏幕上绘制的线条）而忽略任何其他不打算绘制线条的动作。 例如，当玩家的手指“静止”时，手指的轻微移动会破坏我的算法。

我考虑了不同的方法，例如存储最后几次触摸并评估它们以确定是否有滑动，但无法正确实施。

这是我迄今为止尝试过的。大多数情况下它运行良好，但玩家经常做不稳定的运动并且完全与我的预期相反。

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

public class TouchInputHandler : AbstractInputHandler {

    private const int SWIPE_MIN_DISTANCE = 35;

    private Vector2 touchStartPoint;

    private Vector2 touchMovePoint;

    void Update () {
        Touch[] touches = Input.touches;
        if (touches.Length == 1) {
            Touch firstTouch = touches [0];
            if (firstTouch.phase == TouchPhase.Began) {
                this.touchStartPoint = firstTouch.position;
                fireNextDirectionChanged (currentDirection);
            } else if (firstTouch.phase == TouchPhase.Moved) {
                this.touchMovePoint = firstTouch.position;
                if (Vector2.Distance(touchStartPoint, touchMovePoint) > SWIPE_MIN_DISTANCE) {
                    detectSwipeDirection ();
                }
            } else if (firstTouch.phase == TouchPhase.Stationary) {
                touchStartPoint.x = touchMovePoint.x;
                touchStartPoint.y = touchMovePoint.y;
            } else if (firstTouch.phase == TouchPhase.Ended) {
                fireNextDirectionChanged (Constants.Direction.NONE);
            }
        }
    }

    private void detectSwipeDirection() {
        float xDiff = touchMovePoint.x - touchStartPoint.x;
        float yDiff = touchMovePoint.y - touchStartPoint.y;
        Constants.Direction nextDirection;
        bool yGreater = Mathf.Abs(yDiff) >= Mathf.Abs(xDiff);
        if (yGreater) {
            // direction is up or down
            nextDirection = yDiff < 0 ? Constants.Direction.DOWN : Constants.Direction.UP;
        } else {
            // direction is left or right
            nextDirection = xDiff < 0 ? Constants.Direction.LEFT : Constants.Direction.RIGHT;
        }

        if (nextDirection != this.currentDirection)
        {
            fireNextDirectionChanged (nextDirection);
            this.currentDirection = nextDirection;
        }
    }
}

Answer 1

我认为您只是忘记了将TouchPhase.Moved 块中的前一个触摸位置设置为当前位置的行。只需添加touchStartPoint = this.touchMovePoint;，它应该可以工作（仅使用鼠标输入进行测试，但逻辑保持不变）。

我还评论了TouchPhase.Stationary 块：我觉得它就像我之前建议的那样，但只有当手指完全不动时。最终代码如下所示：

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

public class TouchInputHandler : AbstractInputHandler
{

    private const int SWIPE_MIN_DISTANCE = 35;

    private Vector2 touchStartPoint;

    private Vector2 touchMovePoint;

    void Update()
    {
        Touch[] touches = Input.touches;
        if(touches.Length == 1)
        {
            Touch firstTouch = touches[0];
            if(firstTouch.phase == TouchPhase.Began)
            {
                this.touchStartPoint = firstTouch.position;
                this.currentDirection = Constants.Direction.NONE;
                fireNextDirectionChanged(currentDirection);
            }
            else if(firstTouch.phase == TouchPhase.Moved)
            {
                this.touchMovePoint = firstTouch.position;
                if(Vector2.Distance(touchStartPoint, touchMovePoint) > SWIPE_MIN_DISTANCE)
                {
                    detectSwipeDirection();
                }
                touchStartPoint = this.touchMovePoint; // <= NEW !
            }
            //else if(firstTouch.phase == TouchPhase.Stationary)
            //{
            //    touchStartPoint.x = touchMovePoint.x;
            //    touchStartPoint.y = touchMovePoint.y;
            //}
            else if(firstTouch.phase == TouchPhase.Ended)
            {
                this.currentDirection = Constants.Direction.NONE;
                fireNextDirectionChanged(Constants.Direction.NONE);
            }
        }
    }

    private void detectSwipeDirection()
    {
        float xDiff = touchMovePoint.x - touchStartPoint.x;
        float yDiff = touchMovePoint.y - touchStartPoint.y;
        Constants.Direction nextDirection;
        bool yGreater = Mathf.Abs(yDiff) >= Mathf.Abs(xDiff);
        if(yGreater)
        {
            // direction is up or down
            nextDirection = yDiff < 0 ? Constants.Direction.DOWN : Constants.Direction.UP;
        }
        else
        {
            // direction is left or right
            nextDirection = xDiff < 0 ? Constants.Direction.LEFT : Constants.Direction.RIGHT;
        }

        if(nextDirection != this.currentDirection)
        {
            fireNextDirectionChanged(nextDirection);
            this.currentDirection = nextDirection;
        }
    }
}

此外，当使用基于游戏距离的距离来检测滑动时，如果您想将项目移植到多分辨率设备，我建议在某处添加Screen.width/height 比率（在Start() 上执行类似SWIPE_MIN_DISTANCE *= Screen.width / BASE_SCREEN_WIDTH 的操作private const int BASE_SCREEN_WIDTH = 1024;)。

希望对你有帮助，