Ios UIPickerView高度约束动画跳跃

我正在为UIPickerView的高度约束设置动画。 视图跳到一个小高度，仍然显示1行，然后设置动画，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？

---

谢谢

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，请确保不要设置“顶部”和“底部”约束，因为这将不允许“自动布局”将“高度”设置为0点。

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，请确保不要设置“顶部”和“底部”约束，因为这将不允许“自动布局”将高度设置为0点。

尝试类似的操作

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

---

这对我很有用。

试试这样的东西

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

---

它适合我。

选择器组件行的高度是多少。签入

func pickerView（pickerView:UIPickerView，rowHeightForComponent:Int）

---

当self.pickerIsClosed==true时返回0。

选择器组件行的高度是多少。签入

func pickerView（pickerView:UIPickerView，rowHeightForComponent:Int）

---

当self.pickerIsClosed==true时返回0。

我遇到了相同的问题。看起来UIPickerView的高度并没有很好的动画效果，或者至少没有像我希望的那样动画效果

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，因为否则它的反应将与没有包装器时的反应相同

 // create and add UIPicker to view
    UIPickerView *picker = [[UIPickerView alloc] init];
    picker.translatesAutoresizingMaskIntoConstraints = NO;
    picker.delegate = self;
    picker.dataSource = self;
    picker.alpha = 0.0;
    _myUiPicker = picker; // weak reference property

    // make wrapper view
    UIView *wrapper = [UIView new];
    wrapper.translatesAutoresizingMaskIntoConstraints = NO;
    wrapper.clipsToBounds = YES;
    [wrapper addSubview:picker];
    [self.view addSubview:wrapper];

    // Picker constraints
    [picker.leadingAnchor constraintEqualToAnchor:wrapper.leadingAnchor].active = YES;
    [picker.trailingAnchor constraintEqualToAnchor:wrapper.trailingAnchor].active = YES;

    // ***** Note this height is not determined by wrapper view ***
    [picker.heightAnchor constraintEqualToConstant:130.0].active = YES;
    // ****
    [picker.topAnchor constraintEqualToAnchor:wrapper.topAnchor].active = YES;

    // wrapper constraints
    [wrapper.leadingAnchor constraintEqualToAnchor:self.view.leadingAnchor].active = YES;
    [wrapper.trailingAnchor constraintEqualToAnchor:self.view.trailingAnchor].active = YES;
    // **** this is the constraint you will animate ***
    NSLayoutConstraint *heightConstraint = [wrapper.heightAnchor constraintEqualToConstant:0.0];
    heightConstraint.active = YES;
    // ****
    NSLayoutConstraint *topConstraint = [wrapper.topAnchor constraintEqualToAnchor:self.view.topAnchor constant:8.0];
    topConstraint.active = YES;
    [self.view layoutIfNeeded]; // initial layout

    // animate picker height and reminderBtn position
    [UIView animateWithDuration:JAPPickerAnimationTime animations:^{
        heightConstraint.constant = 130.0; // from 0 to 130
        picker.alpha = 1.0; // make is show
        [self.view layoutIfNeeded];
    }];

---

我也有同样的问题。看起来UIPickerView的高度并没有很好的动画效果，或者至少没有像我希望的那样动画效果

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，因为否则它的反应将与没有包装器时的反应相同

 // create and add UIPicker to view
    UIPickerView *picker = [[UIPickerView alloc] init];
    picker.translatesAutoresizingMaskIntoConstraints = NO;
    picker.delegate = self;
    picker.dataSource = self;
    picker.alpha = 0.0;
    _myUiPicker = picker; // weak reference property

    // make wrapper view
    UIView *wrapper = [UIView new];
    wrapper.translatesAutoresizingMaskIntoConstraints = NO;
    wrapper.clipsToBounds = YES;
    [wrapper addSubview:picker];
    [self.view addSubview:wrapper];

    // Picker constraints
    [picker.leadingAnchor constraintEqualToAnchor:wrapper.leadingAnchor].active = YES;
    [picker.trailingAnchor constraintEqualToAnchor:wrapper.trailingAnchor].active = YES;

    // ***** Note this height is not determined by wrapper view ***
    [picker.heightAnchor constraintEqualToConstant:130.0].active = YES;
    // ****
    [picker.topAnchor constraintEqualToAnchor:wrapper.topAnchor].active = YES;

    // wrapper constraints
    [wrapper.leadingAnchor constraintEqualToAnchor:self.view.leadingAnchor].active = YES;
    [wrapper.trailingAnchor constraintEqualToAnchor:self.view.trailingAnchor].active = YES;
    // **** this is the constraint you will animate ***
    NSLayoutConstraint *heightConstraint = [wrapper.heightAnchor constraintEqualToConstant:0.0];
    heightConstraint.active = YES;
    // ****
    NSLayoutConstraint *topConstraint = [wrapper.topAnchor constraintEqualToAnchor:self.view.topAnchor constant:8.0];
    topConstraint.active = YES;
    [self.view layoutIfNeeded]; // initial layout

    // animate picker height and reminderBtn position
    [UIView animateWithDuration:JAPPickerAnimationTime animations:^{
        heightConstraint.constant = 130.0; // from 0 to 130
        picker.alpha = 1.0; // make is show
        [self.view layoutIfNeeded];
    }];

---

谢谢，但同样的问题。您为PickerView设置了哪些约束？尾随、前导、高度、顶部、底部在这种情况下，将高度更改为0将不起作用，因为自动布局引擎需要打破约束。尝试设置垂直和水平中心约束，设置宽度和高度约束，只需设置高度约束的出口并进行更新。根据需要进行更改。谢谢，但问题相同。您为PickerView设置了哪些约束？尾随、前导、高度、顶部、，在这种情况下，将“高度”更改为0将不起作用，因为自动布局引擎需要打破约束。尝试设置垂直和水平中心约束，并设置宽度和高度约束，只需导出高度约束并进行更新。根据需要进行更改。在动画块完成时也重新加载选择器视图。在动画块完成时也重新加载选择器视图。听起来是一个不错的解决方案-可以显示一些代码吗？我不明白你的最后一句话（即独立约束需求）。你能详细说明一下你是如何做到这一点的吗？@iKK我添加了一个代码示例。关于独立高度，我的意思是，设置UIPickerView高度的约束与充当包装器的UIView的高度无关或不相关。听起来是个不错的解决方案-您能展示一些代码吗？我不明白你的最后一句话（即独立约束需求）。你能详细说明一下你是如何做到这一点的吗？@iKK我添加了一个代码示例。关于独立高度，我的意思是，设置UIPickerView高度的约束与充当包装器的UIView的高度无关或不相关。