我需要仅使用一根手指的 Action 来根据用户的 Action 旋转 UIImageview。为此,我使用旋转手势,然后使用以下代码覆盖 TouchMoved:
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
let touch = touches.first
if touch!.view === rotateImageView {
let position = touch!.locationInView(self.view)
let target = rotateImageView.center
let angle = atan2(target.y-position.y, target.x-position.x)
rotateImageView.transform = CGAffineTransformMakeRotation(angle)
}
}
只要用户停止触摸屏幕并在屏幕的另一部分进行 Action ,此功能就会起作用。在这种情况下,当用户开始移动手指时,UIImageview 会旋转到不需要的位置。我需要保持 UIImageview 的原始旋转位置以避免这种情况,但我不知道该怎么做。
这张 gif 显示了我的项目原型(prototype)的当前行为。正如您所看到的,当我开始在右侧旋转时,火焰图标突然出现在触摸点附近,这就是我想要防止的情况。
2016 年 8 月 23 日更新
我使用了 Matt 和 Dasem 建议的使用 CGAffineTransformRotate,但我仍然看到了跳跃。我采用了 Dasem 代码并适应了我的项目,如下所示(如果适应错误,请告诉我):
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
origin = (touches.first?.locationInView(self.view))!
//save the current transform
tempTransform = rotateImageView.transform
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
let touchPoint = touches.first?.locationInView(self.view)
xOffSet = CGVector(dx:(origin.x)-rotateImageView.center.x, dy:(origin.x) - rotateImageView.center.y)
yOffSet = CGVector(dx:touchPoint!.x - rotateImageView.center.x, dy:touchPoint!.y - rotateImageView.center.y)
let angle = atan2(yOffSet.dy,yOffSet.dx) - atan2(xOffSet.dy,xOffSet.dx)
rotateImageView.transform = CGAffineTransformRotate(tempTransform, angle)
}
当用户触摸触摸屏的不同区域时,此更改会产生类似的效果。在此 gif 中,我更改了图像并删除了图标,以使效果更加明显。
更新解决方案
使用 Jasem 更新重新应用代码并且它有效,以下代码在不使用子类化的情况下解决了问题
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
origin = (touches.first?.locationInView(self.view))!
xOffSet = CGVector(dx:(origin.x)-rotateImageView.center.x, dy:(origin.y) - rotateImageView.center.y)
startingAngle = atan2(xOffSet.dy,xOffSet.dx)
//save the current transform
tempTransform = rotateImageView.transform
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
let touchPoint = touches.first?.locationInView(self.view)
yOffSet = CGVector(dx:touchPoint!.x - rotateImageView.center.x, dy:touchPoint!.y - rotateImageView.center.y)
let angle = atan2(yOffSet.dy,yOffSet.dx)
let deltaAngle = angle - startingAngle!
rotateImageView.transform = CGAffineTransformRotate(tempTransform, deltaAngle)
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
startingAngle = nil
}
//reset in case drag is cancelled
override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {
rotateImageView.transform = tempTransform
startingAngle = nil
}
最佳答案
你可能想将 self.superview 更改为 self.view (我的是子类)
var xOffSet:CGVector = CGVectorMake(0, 0)
var yOffSet:CGVector = CGVectorMake(0, 0)
var origin:CGPoint = CGPointZero
var tempTransform=CGAffineTransform()
var startingAngle:CGFloat?
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
origin = (touches.first?.locationInView(self.superview))!
xOffSet = CGVector(dx:(origin.x)-self.center.x, dy:(origin.y) - self.center.y)
startingAngle = atan2(xOffSet.dy,xOffSet.dx)
//save the current transform
tempTransform = self.transform
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
let touchPoint = touches.first?.locationInView(self.superview)
yOffSet = CGVector(dx:touchPoint!.x - self.center.x, dy:touchPoint!.y - self.center.y)
let angle = atan2(yOffSet.dy,yOffSet.dx)
let deltaAngle = angle - startingAngle!
self.transform = CGAffineTransformRotate(tempTransform, deltaAngle)
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
startingAngle = nil
}
//reset in case drag is cancelled
override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {
self.transform = tempTransform
startingAngle = nil
}
关于swift - 旋转手势产生不需要的旋转,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/39091563/