使用UIButton实现UIDatePicker和UIPickerView

Question

我正在使用UIPickerView和UIDatePicker作为用户输入设备的iOS应用程序中实现用户表单。 我已经将这些实现为场景中主UIViewController外部的视图，并通过添加和删除约束使用自动autolayout来显示和隐藏它们。

这是我的问题：我维护着单独的约束和隐藏/显示方法，以对这些视图中的每一个进行动画处理。 这是很多重复的代码，我觉得必须有一种更简洁的方法来执行此操作，因为这似乎是iOS应用程序中非常常见的设计模式。 我在这方面还很陌生，所以我觉得我缺少一些东西。

对于UIButtons使用多个输入设备，是否有比这更好的设计模式？

这是我用来维护此代码的示例...

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()
    })       
}

这是我的情节提要的屏幕截图... 情节提要

Answer 1

你们，我想出了一种更好的方法！

我最初所缺少的是，当您从超级视图中删除视图时，所有约束都将被删除。 这使事情变得容易得多。

我为当前显示的视图保留了1个约束类变量，因此该视图可以向下移动动画。

我还添加了“设置”功能以将视图放置在viewdidload() 。 如果没有此视图，则视图始终会在第一次出现时从顶部开始进行动画处理（无法解决此问题）。

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()
        })
    }
}