Spritekit Animation Not Changing

问题

I have a virtual control pad in my game. If I tap and hold on one of the direction buttons, the player moves in the correct direction and shows the proper images and animation. However, if I slide my finger from one control to another one (say right to down), the player moves down but the image and animation don't change until I lift my finger. Below is my code for handling the touches:

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in (touches as! Set<UITouch>) {
        let location = touch.location(in: cameraNode)

        if upRect.contains(location) {
            moveXDirection = 0
            moveYDirection = 1
            isIdle = false
            playerSprite.walkUpPlayer()
        } else if rightRect.contains(location) {
            moveXDirection = 1
            moveYDirection = 0
            isIdle = false
            playerSprite.walkLRPlayer()
        } else if downRect.contains(location) {
            moveXDirection = 0
            moveYDirection = -1
            isIdle = false
            playerSprite.walkDownPlayer()
        } else if leftRect.contains(location) {
            moveXDirection = -1
            moveYDirection = 0
            isIdle = false
             playerSprite.walkLRPlayer()
        }
        if !isIdle && moveXDirection != 0 {
            playerSprite.xScale = moveXDirection
        }
    }
}

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in (touches as! Set<UITouch>) {
        let location = touch.location(in: cameraNode)

        if upRect.contains(location) {
            moveXDirection = 0
            moveYDirection = 1
            isIdle = false
        } else if rightRect.contains(location) {
            moveXDirection = 1
            moveYDirection = 0
            isIdle = false
        } else if downRect.contains(location) {
            moveXDirection = 0
            moveYDirection = -1
            isIdle = false
        } else if leftRect.contains(location) {
            moveXDirection = -1
            moveYDirection = 0
            isIdle = false
        }
        if !isIdle && moveXDirection != 0 {
            playerSprite.xScale = moveXDirection
        }

    }
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    idlePlayer()
}

My code for changing the player animation is:

func idlePlayer() {
    removeAllActions()
}

func walkLRPlayer() {
    removeAllActions()
    run(SKAction.repeatForever(walkLRAnimation!))
}

func walkUpPlayer() {
    removeAllActions()
    run(SKAction.repeatForever(walkUpAnimation!))
}

func walkDownPlayer() {
    removeAllActions()
    run(SKAction.repeatForever(walkDownAnimation!))
}

Any suggestions would be greatly appreciated.

回答1:

Your player starts with a direction in touchesBegan and stops it on touchesEnded. The problem is that you don't handle the direction changes on touchesMoves.

Lets create a global variable that will tell us if we changed the direction.

var previous_direction : Int = -1 // idle state

On the touches functions, add the previous_direction behaviour.

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in (touches as! Set<UITouch>) {

        // we start with previous_direction being the start direction

        if upRect.contains(location) {
            previous_direction = 0  // up
        } else if rightRect.contains(location) {
            previous_direction = 1  // right
        } else if downRect.contains(location) {
            previous_direction = 2  // down
        } else if leftRect.contains(location) {
            previous_direction = 3  // left
        }
    }
}

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in (touches as! Set<UITouch>) {

        // we create a current_direction also
        var current_direction : Int = -1

        // get current_direction 
        if upRect.contains(location) {
            current_direction = 0 // up
        } else if rightRect.contains(location) {
            current_direction = 1 // right
        } else if downRect.contains(location) {
            current_direction = 2 // down
        } else if leftRect.contains(location) {
            current_direction = 0 // left
        }

        // now we compare if the current_direction is different from previous_direction
        if current_direction != previous_direction
        {
             player.removeAllActions()

             // attribute new direction
             if current_direction == 0 {
                   playerSprite.walkUpPlayer()
             } else if current_direction == 1 {
                   walkLRPlayer.walkLRPlayer()
             } else if current_direction == 2 {
                   walkLRPlayer.walkDownPlayer()
             } else if current_direction == 3 {
                   walkLRPlayer.walkLRPlayer() } 

             // we prepare previous_direction for the next time he enters this function
             previous_direction = current_direction  
        }
    }
 }

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    // reset previous_direction
    previous_direction = - 1 // idle state
}

来源：https://stackoverflow.com/questions/54227703/spritekit-animation-not-changing