在Unity中实现Android上的滑动手势

Question

我想让Unity识别我正在从左向右滑动，我已经解决了这个问题，但是我的问题是在我没有抬起手指之前它不会理解我的操作。

我的问题是如何使它知道我先向右滑动，然后向左滑动，再向右滑动，而不需要抬起手指。

以下是我目前的代码：

using UnityEngine;
using System.Collections;

public class Gestures : MonoBehaviour {

private Vector2 fingerStart;
private Vector2 fingerEnd;

public int leftRight = 0;
public int upDown = 0;

void Update () {
    foreach(Touch touch in Input.touches)
    {
        if (touch.phase == TouchPhase.Began)
        {
            fingerStart = touch.position;
            fingerEnd  = touch.position;
        }
        if (touch.phase == TouchPhase.Moved )
        {
            fingerEnd = touch.position;

        }
        if(touch.phase == TouchPhase.Ended)
        {
            if((fingerStart.x - fingerEnd.x) > 80 || (fingerStart.x - fingerEnd.x) < -80) // Side to side Swipe
            {
                leftRight ++;
            }
            else if((fingerStart.y - fingerEnd.y) < -80 || (fingerStart.y - fingerEnd.y) > 80) // top to bottom swipe
            {
                upDown ++;

            }
            if(leftRight >= 3){

                leftRight = 0;
            }
            if(upDown >= 4){

                upDown = 0;
            }
        }
    }
}
}

- Graeme MacDonald

Answer 1

您面临的问题是因为您在TouchPhase.Ended中进行了检查。您想要做的是在TouchPhase.Moved中执行检查，并使用较小的值更改（如果代码不起作用，则使用80在Ended中，尝试使用10等）。

Unity关于TouchPhase的文档 http://docs.unity3d.com/ScriptReference/TouchPhase.html

    foreach(Touch touch in Input.touches)
    {

        if (touch.phase == TouchPhase.Began)
        {
            fingerStart = touch.position;
            fingerEnd  = touch.position;
        }
        if (touch.phase == TouchPhase.Moved )
        {
            fingerEnd = touch.position;

            if((fingerStart.x - fingerEnd.x) > 80 || 
               (fingerStart.x - fingerEnd.x) < -80) // Side to side Swipe
            {
                leftRight ++;
            }
            else if((fingerStart.y - fingerEnd.y) < -80 || 
                    (fingerStart.y - fingerEnd.y) > 80) // top to bottom swipe
            {
                upDown ++;

            }
            if(leftRight >= 3){

                leftRight = 0;
            }
            if(upDown >= 4){

                upDown = 0;
            }

            //After the checks are performed, set the fingerStart & fingerEnd to be the same
            fingerStart = touch.position;   

        }
        if(touch.phase == TouchPhase.Ended)
        {
            leftRight = 0;
            upDown = 0;
            fingerStart = Vector2.zero;
            fingerEnd = Vector2.zero;
        }

如果您想明确地检查模式（即从左到右，然后从右到左），而不仅仅是像您现有的代码那样检查它是否是一些横向/纵向移动，请尝试以下代码。只需记住包括System.Collections.Generic和System.Linq命名空间。

private Vector2 fingerStart;
private Vector2 fingerEnd;

public enum Movement
{
    Left,
    Right, 
    Up,
    Down
};

public List<Movement> movements = new List<Movement>();


void Update () {
    foreach(Touch touch in Input.touches)
    {

        if (touch.phase == TouchPhase.Began) {
            fingerStart = touch.position;
            fingerEnd  = touch.position;
        }

        if(touch.phase == TouchPhase.Moved) {
            fingerEnd = touch.position;

            //There is more movement on the X axis than the Y axis
            if(Mathf.Abs(fingerStart.x - fingerEnd.x) > Mathf.Abs(fingerStart.y - fingerEnd.y)) {

                //Right Swipe
                if((fingerEnd.x - fingerStart.x) > 0)
                    movements.Add(Movement.Right);
                //Left Swipe
                else
                    movements.Add(Movement.Left);

            }

            //More movement along the Y axis than the X axis
            else {
                //Upward Swipe
                if((fingerEnd.y - fingerStart.y) > 0)
                    movements.Add(Movement.Up);
                //Downward Swipe
                else
                    movements.Add(Movement.Down);
            }
            //After the checks are performed, set the fingerStart & fingerEnd to be the same
            fingerStart = touch.position;   

            //Now let's check if the Movement pattern is what we want
            //In this example, I'm checking whether the pattern is Left, then Right, then Left again
            Debug.Log (CheckForPatternMove(0, 3, new List<Movement>() { Movement.Left, Movement.Right, Movement.Left } ));
        }


        if(touch.phase == TouchPhase.Ended)
        {
            fingerStart = Vector2.zero;
            fingerEnd = Vector2.zero;
            movements.Clear();
        }
    }
}


private bool CheckForPatternMove (int startIndex, int lengthOfPattern, List<Movement> movementToCheck) {

    //If the currently stored movements are fewer than the length of the pattern to be detected
    //it can never match the pattern. So, let's get out
    if(lengthOfPattern > movements.Count)
        return false;

    //In case the start index for the check plus the length of the pattern
    //exceeds the movement list's count, it'll throw an exception, so lets get out
    if(startIndex + lengthOfPattern > movements.Count)
        return false;

    //Populate a temporary list with the respective elements
    //from the movement list
    List<Movement> tMovements = new List<Movement>();
    for(int i = startIndex; i < startIndex + lengthOfPattern; i++)
        tMovements.Add(movements[i]);

    //Now check whether the sequence of movements is the same as the pattern you want to check for
    //The SequenceEqual method is in the System.Linq namespace
    return tMovements.SequenceEqual(movementToCheck);
}

编辑 添加了更多代码作为示例

    //The idea of a pattern match is to check for the exact same set of swipe gesture.
    //This requires the following conditions to be met
    // (a) The List of movements that need to be checked must be at least as long as the List of movements to check against.
    // (b) The correct indices should be used for the startIndex. In this case I'm just using 0 as the startIndex.
    // (c) Remember to clear the List right after you get a true return from the method, otherwise the next return will most likely be a false. 

    //Example - Training set is Left -> Right -> Left (This is what we want to check)
    // Step 1 - User swipes LEFT, method returns false because there are too few Movements to check
    // Step 2 - User swipes RIGHT, method returns false (same reason as above)

    // Step 3a - User swipes RIGHT (L, R, R now) - false, incorrect pattern (L, R, R instead of L, R, L)
    // Step 3b - User swipes LEFT (L, R, L now) - TRUE, Correct pattern!

    //Immediately clear if Step 3b happens otherwise Step 4 will occur

    // Step 4 - User swipes L or R (direction is immaterial right now), and method will return FALSE
    // if you use the last three indexes!



    //Pre-populating the movements List with L, R, L
    movements = new List<Movement>()
    {
        Movement.Left,
        Movement.Right,
        Movement.Left
    };

    //Checking a match against an L, R, L training set
    //This prints true to the console
    Debug.Log (CheckForPatternMove(0, 3, new List<Movement>() { Movement.Left, Movement.Right, Movement.Left }  ));

这是我的更新函数的样子。请注意在Input.touch上使用GetMouseButton的用法。

void Update () {

    //Example usage in Update. Note how I use Input.GetMouseButton instead of Input.touch

    //GetMouseButtonDown(0) instead of TouchPhase.Began
    if (Input.GetMouseButtonDown(0)) {
        fingerStart = Input.mousePosition;
        fingerEnd  = Input.mousePosition;
    }

    //GetMouseButton instead of TouchPhase.Moved
    //This returns true if the LMB is held down in standalone OR
    //there is a single finger touch on a mobile device
    if(Input.GetMouseButton(0)) {
        fingerEnd = Input.mousePosition;

        //There was some movement! The tolerance variable is to detect some useful movement
        //i.e. an actual swipe rather than some jitter. This is the same as the value of 80
        //you used in your original code.
        if(Mathf.Abs(fingerEnd.x - fingerStart.x) > tolerance || 
           Mathf.Abs(fingerEnd.y - fingerStart.y) > tolerance) {

            //There is more movement on the X axis than the Y axis
            if(Mathf.Abs(fingerStart.x - fingerEnd.x) > Mathf.Abs(fingerStart.y - fingerEnd.y)) {
                //Right Swipe
                if((fingerEnd.x - fingerStart.x) > 0)
                    movements.Add(Movement.Right);
                //Left Swipe
                else
                    movements.Add(Movement.Left);
            }

            //More movement along the Y axis than the X axis
            else {
                //Upward Swipe
                if((fingerEnd.y - fingerStart.y) > 0)
                    movements.Add(Movement.Up);
                //Downward Swipe
                else
                    movements.Add(Movement.Down);
            }

            //After the checks are performed, set the fingerStart & fingerEnd to be the same
            fingerStart = fingerEnd;

            //Now let's check if the Movement pattern is what we want
            //In this example, I'm checking whether the pattern is Left, then Right, then Left again
            Debug.Log (CheckForPatternMove(0, 3, new List<Movement>() { Movement.Left, Movement.Right, Movement.Left } ));
        }
    }

    //GetMouseButtonUp(0) instead of TouchPhase.Ended
    if(Input.GetMouseButtonUp(0)) {
        fingerStart = Vector2.zero;
        fingerEnd = Vector2.zero;
        movements.Clear();
    }


}

- Venkat at Axiom Studios

---

如果这个答案对您有帮助，请将其标记为正确答案 :) - Venkat at Axiom Studios

快速问题，我正在尝试您发布的第二段代码，但Unity在CheckForPatternMove()函数的前两个返回语句上抛出错误，说“需要可转换为`bool'类型的对象才能使用return语句”。我已经尝试将两者都设置为false和true，但是当我尝试测试它是否检测到（LRL）模式时，它总是返回false。我只是将第二段代码复制粘贴到一个新脚本中，并添加了上述命名空间，我做错了什么？ - Graeme MacDonald

啊，第一个是我的错误。在前两个检查中，你需要返回false。对于你的第二个问题，可能是以下原因之一：（a）使用了不正确的索引进行检查，（b）由于低容差而添加了一些额外的点，（c）Input.touch每次返回相当多的点，这些点都被累加了。我已经编辑了我的帖子以详细说明我如何使用该方法。希望这能有所帮助。请注意，我通常使用Input.GetMouseButton而不是Input.Touch。鼠标输入在移动设备上也可用，并返回一���单独的点。 - Venkat at Axiom Studios

我使用80作为容差，但是我会出现抖动，当我在游戏对象上滑动时，事件仍然会触发，而且事件甚至会在具有此脚本的游戏对象之外触发。如果您能告诉我如何解决这些问题，那将非常好。@VenkatatAxiomStudios - Junaid Qadir Shekhanzai

@JeyKeu 这些脚本没有检查您当前是否正在点击/触摸任何游戏对象。您可以在Update函数中包含一个Raycast，如果Raycast击中您想要移动的游戏对象，则计算滑动方向等。 - Venkat at Axiom Studios