override func touchesMoved(_ touches:Set<UITouch>, with event:UIEvent?) { //需要先判断是否触屏区域是否在图像内,省略 if!isTouchInImageView{ return; } let touch = touches.first let touchPoint = touch?.location(in:self.view) let touchPrePoint = touch?.previousLocation(in:self.view) let disX = (touchPoint?.x)!- (touchPrePoint?.x)! let disY = (touchPoint?.y)!- (touchPrePoint?.y)! var centerPoint = self.imageView.center centerPoint.x += disX centerPoint.y += disY self.imageView.center = centerPoint }