Question

我正在制作UIPickerView的高度限制。视图跳转到一个小高度，仍然显示1行，然后动画直到高度为0.

UIView.animate(withDuration: 0.5, animations: {
        self.timePickerHeightConstraint.constant =    self.pickerIsClosed ? 216 : 0
        self.view.layoutIfNeeded()
    }) { compilation in
        self.pickerIsClosed = !self.pickerIsClosed
    }

有什么建议吗？唐卡

Answer 1

您应该在动画块之外更改约束常量值

self.timePickerHeightConstraint.constant =    self.pickerIsClosed ? 216 : 0

UIView.animate(withDuration: 0.5, animations: {
    self.view.layoutIfNeeded()
}) { compilation in
    self.pickerIsClosed = !self.pickerIsClosed
}

另外，请确保不设置“上限”和“下限”约束，因为不允许自动布局将高度设置为0磅。

Answer 2

尝试这样的事情，

func showPickerView(_ animated: Bool) {
    weak var weakSelf = self
    UIView.animate(withDuration: (animated ? kPickerView_AppearanceAnimationDuration : 0.0), delay: (animated ? kPickerView_AppearanceAnimationDelay : 0.0), options: (animations as! UIViewAnimationOptionCurveEaseInOut), {() -> Void in
        weakSelf!.pickerViewContainerView.transform = CGAffineTransform(translationX: 0, y: 0)
    }, completion: {(finished: Bool) -> Void in
        weakSelf!.view.layoutIfNeeded()
    })
}

func hidePickerView(_ animated: Bool) {
    weak var weakSelf = self
    UIView.animate(withDuration: (animated ? kPickerView_DisappearanceAnimationDuration : 0.0), delay: (animated ? kPickerView_DisappearanceAnimationDelay : 0.0), options: (animations as! UIViewAnimationOptionCurveEaseInOut), {() -> Void in
        weakSelf!.pickerViewContainerView.transform = CGAffineTransform(translationX: 0, y: kPickerView_Height)
    }, completion: {(finished: Bool) -> Void in

它对我有用。

Answer 3

拾取器组件行的高度是多少。签入

func pickerView（pickerView：UIPickerView，rowHeightForComponent组件：Int）

当self.pickerIsClosed == true时返回0。

Answer 4

我遇到了同样的问题。看起来UIPickerView的高度并没有真正有效，或者至少以我希望的方式生成。

我找到的解决方法是将UIPickerView包装在UIView中，将UIView的clipsToBounds设置为true，然后在UIView包装器的高度约束上执行动画，而不是直接使用UIPickerView。需要注意的一点是，要使其工作，UIPicker视图的高度必须独立于包装器视图的高度进行约束，否则它将以与没有包装器相同的方式作出反应。

UIPickerView高度约束动画跳转

4 个答案: