ios - 使用 UIButton 实现 UIDatePicker 和 UIPickerView

Question

我正在 iOS 应用程序中实现一个用户表单，该应用程序使用 UIPickerView 和 UIDatePicker 作为用户的输入设备。我已将其中每个 View 实现为场景中主 UIViewController 的外部 View ，并通过添加和删除约束来使用 autolayout 显示和隐藏它们。

这是我的问题:我正在维护单独的约束和隐藏/显示方法，以对每个 View 进行动画输入和输出。这是很多重复代码，我觉得必须有一种更简洁的方法来做到这一点，因为它似乎是 iOS 应用程序中非常常见的设计模式。我对此还很陌生，所以我觉得我错过了一些东西。

对于 UIButtons 使用多个输入设备，是否有比这更好的设计模式？

这是我用来维护这个的代码示例...

var datePickerViewBottomConstraint: NSLayoutConstraint!
var datePickerViewTopConstraint: NSLayoutConstraint!
var storagePickerViewBottomConstraint: NSLayoutConstraint!
var storagePickerViewTopConstraint: NSLayoutConstraint!

@IBAction func storageButtonClicked(sender: UITextField) {

    storagePickerView.translatesAutoresizingMaskIntoConstraints = false
    storagePickerViewBottomConstraint = storagePickerView.bottomAnchor.constraintEqualToAnchor(view.bottomAnchor)

    UIView.animateWithDuration(0.4, animations: {
        self.storagePickerViewTopConstraint.active = false
        self.storagePickerViewBottomConstraint.active = true
    self.view.layoutIfNeeded()
    })
}

@IBAction func datePumpedClicked(sender: UIButton) {

    datePickerView.translatesAutoresizingMaskIntoConstraints = false
    datePickerViewBottomConstraint = datePickerView.bottomAnchor.constraintEqualToAnchor(view.bottomAnchor)

    UIView.animateWithDuration(0.4, animations: {
        self.datePickerViewTopConstraint.active = false
        self.datePickerViewBottomConstraint.active = true
        self.view.layoutIfNeeded()
    })
}

@IBAction func datePickerDismiss(sender: AnyObject) {
    datePumpedLabel.setTitle(Global.dateFormatter.stringFromDate(datePicker.date), forState: UIControlState.Normal)

    datePickerView.translatesAutoresizingMaskIntoConstraints = false
    datePickerViewTopConstraint = datePickerView.topAnchor.constraintEqualToAnchor(view.bottomAnchor)

    UIView.animateWithDuration(0.4, animations: {
        self.datePickerViewBottomConstraint.active = false
        self.datePickerViewTopConstraint.active = true
        self.view.layoutIfNeeded()
    })  
}

@IBAction func storagePickerDismiss(sender: AnyObject) {

    storagePickerView.translatesAutoresizingMaskIntoConstraints = false
    storagePickerViewTopConstraint = storagePickerView.topAnchor.constraintEqualToAnchor(view.bottomAnchor)

    UIView.animateWithDuration(0.4, animations: {
        self.storagePickerViewBottomConstraint.active = false
        self.storagePickerViewTopConstraint.active = true
        self.view.layoutIfNeeded()
    })       
}

这是我的 Storyboard的屏幕截图...... Storyboard

Answer 1

你们，我找到了更好的方法!

我最初遗漏的是，当您从 super View 中删除 View 时，所有约束都会被删除。这使事情变得容易得多。

我为当前显示的 View 保留了 1 个约束类变量，因此 View 可以向下动画移动。

我还添加了一个“setup”函数来在 viewdidload() 上获取 View 。如果没有这个， View 在第一次出现时总是会从顶部开始动画(无法找到解决这个问题的方法)。

这是我使用的:

var secondaryMenuBottomConstraint: NSLayoutConstraint!

func setupSecondaryMenu(secondaryMenu: UIView){

    secondaryMenu.translatesAutoresizingMaskIntoConstraints = false

    let topConstraint = secondaryMenu.topAnchor.constraintEqualToAnchor(view.bottomAnchor)
    let leftConstraint = secondaryMenu.leftAnchor.constraintEqualToAnchor(view.leftAnchor)
    let rightConstraint = secondaryMenu.rightAnchor.constraintEqualToAnchor(view.rightAnchor)

    view.addSubview(secondaryMenu)
    NSLayoutConstraint.activateConstraints([topConstraint, leftConstraint, rightConstraint])
    self.view.layoutIfNeeded()
    secondaryMenu.removeFromSuperview()

}

func showSecondaryMenu(secondaryMenu: UIView){
    //Close any open keyboards
    amountTextField.resignFirstResponder()
    notesTextField.resignFirstResponder()

    //Add the view and then add constraints to show the submenu below the current view
    secondaryMenu.translatesAutoresizingMaskIntoConstraints = false
    let topConstraint = secondaryMenu.topAnchor.constraintEqualToAnchor(view.bottomAnchor)
    let leftConstraint = secondaryMenu.leftAnchor.constraintEqualToAnchor(view.leftAnchor)
    let rightConstraint = secondaryMenu.rightAnchor.constraintEqualToAnchor(view.rightAnchor)

    view.addSubview(secondaryMenu)
    NSLayoutConstraint.activateConstraints([topConstraint, leftConstraint, rightConstraint])

    secondaryMenuBottomConstraint = secondaryMenu.bottomAnchor.constraintEqualToAnchor(view.bottomAnchor)

    //animate the view up into place
    UIView.animateWithDuration(0.4, animations: {
        topConstraint.active = false
        self.secondaryMenuBottomConstraint.active = true
        self.view.layoutIfNeeded()
    })
}

func dismissSecondaryMenu(secondaryMenu: UIView){
    if secondaryMenu.superview != nil {
        secondaryMenu.translatesAutoresizingMaskIntoConstraints = false
        let secondaryMenuTopConstraint = secondaryMenu.topAnchor.constraintEqualToAnchor(view.bottomAnchor)
        self.secondaryMenuBottomConstraint.active = false

        UIView.animateWithDuration(0.4, animations: {
            secondaryMenuTopConstraint.active = true

            self.view.layoutIfNeeded()
        }, completion: {(finished:Bool) in
                secondaryMenu.removeFromSuperview()
        })
    }
}