约束动画不起作用Swift

Question

我正在尝试为UIImageView制作动画，基本上在整个视图在屏幕上的原始位置。只要我按下一个按钮，视图就会向左滑动，只能看到它的一部分。 constraint.constant的值为：

1. 屏幕位置= 0（这是起始位置
2. 关闭屏幕位置= -200（应该是到达点）

这是代码。

func constraintAnimation (duration: Double, animatedConstraint: NSLayoutConstraint, finalConstantValue: CGFloat) {

    self.view.layoutIfNeeded()
    UIImageView.animateWithDuration(duration, animations: {
    animatedConstraint.constant = finalConstantValue

    })
    self.view.layoutIfNeeded()
    println("")

}

Answer 1

将您的代码更改为此并尝试

func constraintAnimation (duration: Double, animatedConstraint: NSLayoutConstraint, finalConstantValue: CGFloat) {
     animatedConstraint.constant = finalConstantValue
    UIImageView.animateWithDuration(duration, animations: {
     self.view.layoutIfNeeded()
     })
     println("")
}

Answer 2

尝试以这种方式书写，下面是在目标-C

中设置按钮动画的简单示例

[UIButton animateWithDuration:0.5 animations:^{
    self.horizontalConstraint.constant+=150;
    [self.checkbut layoutIfNeeded];
} completion:^(BOOL finished) {

}];

您的代码

func constraintAnimation (duration: Double, animatedConstraint: NSLayoutConstraint, finalConstantValue: CGFloat) {

UIImageView.animateWithDuration(duration, animations: {
animatedConstraint.constant = finalConstantValue//Set the constant relative to initial positon like i have didi in above example
 self.view.layoutIfNeeded()
 })
 println("")

}