Swift - 这个UILongPressGestureRecognizer-Code出了什么问题？

Question

我正试图在两侧长按时向左和向右移动节点。因此，如果左侧有长按，节点向左移动，长按在右侧，节点向右移动。我将此代码放在didMoveToView中，但它对我不起作用。我究竟做错了什么？

func beginTouchRecognizer(){
    let longPress = UILongPressGestureRecognizer(target: self, action: Selector("longPressTouch:"))
    longPress.minimumPressDuration = 1.0
    longPress.numberOfTapsRequired = 0
    longPress.numberOfTouchesRequired = 1

   self.view?.addGestureRecognizer(longPress)
}

let WidthOfTapArea: CGFloat = 100

func longPressTouch(recognizer: UILongPressGestureRecognizer) {
    let location = recognizer.locationInView(self.view)
    if location.x < CGRectGetMidX(self.frame) {
        hero.position.x -= WidthOfTapArea
    } else {
        hero.position.x += WidthOfTapArea
    }
}