以编程方式创建一个在横向和纵向工作的 UIPickerView

Question

我想创建一个最小的 UIPickerView，它在纵向和横向格式中看起来都不错，而且它工作......有点。 我按下按钮后添加了pickerView，完成后将其隐藏。 pickerView 工作正常：

• 当我以纵向或横向启动应用程序并按下按钮而不改变方向时
• 当我在屏幕上显示 pickerView 时，更改方向可以正常工作，pickerView 会更改大小

但是在一个方向启动并在单击按钮以显示pickerView之前更改方向时效果不佳，然后会显示以下内容： in portait orientation in paysage orientation

这是代码（单视图应用程序，情节提要中只有一个按钮：myButton，带有触摸动作 touchMyButton）

class myViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {

@IBOutlet weak var myButton: UIButton!
var myPickerView: UIPickerView! = UIPickerView(frame:CGRectMake(0.0, 0.0, UIScreen.mainScreen().bounds.width, 162))
var activePickerView: Int = 0

override func viewDidLoad() {
    super.viewDidLoad()
    myPickerView.tag = 1
    myPickerView.delegate = self
    myPickerView.autoresizingMask = [.FlexibleWidth]
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}


@IBAction func touchMyButton(sender: AnyObject) {
    if (activePickerView == 0)
    {
        activePickerView = myPickerView.tag
        myPickerView.selectRow(5, inComponent:0, animated:false)
        myPickerView.backgroundColor = UIColor.init(white:0.80, alpha:0.80)
        myPickerView.frame = CGRectMake(0.0, 100.0, UIScreen.mainScreen().bounds.width, 0.0)
        self.view.layoutIfNeeded()
        self.view.addSubview(myPickerView)
        myPickerView.setNeedsDisplay()

        UIView.animateWithDuration(0.5, delay:0.0, options:UIViewAnimationOptions.CurveEaseInOut, animations:{
            self.view.layoutIfNeeded()
            self.myPickerView.frame = CGRectMake(0.0, 100.0, self.myPickerView.frame.width, 162)
            }, completion: { _ in
        })
    }
    else
    {
        self.selectPickerView()
    }
}

func selectPickerView(){
    if (activePickerView == myPickerView.tag)
    {
        let _ = myPickerView.selectedRowInComponent(0)
        let framePV = self.myPickerView.frame

        UIView.animateWithDuration(0.5, delay:0.0, options:UIViewAnimationOptions.CurveEaseInOut, animations:{
            self.view.layoutIfNeeded()
            self.myPickerView.frame = CGRectMake(0.0, framePV.origin.y, framePV.width, 0.0 )
            }, completion:{ _ in
                self.myPickerView.removeFromSuperview()
        })
    }
    activePickerView = 0
}

// MARK: UIPickerViewDataSource methods
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int
{   return 1    }

func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int
{   return 10   }

func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String?
{   return "Row \(row)" }

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    activePickerView = pickerView.tag
    selectPickerView()
}


override func didRotateFromInterfaceOrientation(fromInterfaceOrientation: UIInterfaceOrientation)
{   self.view.layoutIfNeeded()  }
}

我迷路了，我看不出我可以改变什么来让它工作

Answer 1

谢谢，我是在约束下做到的（这不是很简单），就像那样

import UIKit

class myViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {

@IBOutlet weak var myButton: UIButton!
var myPickerView: UIPickerView! = UIPickerView()
var activePickerView: Int = 0

override func viewDidLoad() {
    super.viewDidLoad()
    myPickerView.tag = 1
    myPickerView.delegate = self
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

@IBAction func touchMyButton(sender: AnyObject) {
    if (activePickerView == 0){
        activePickerView = myPickerView.tag
        myPickerView.selectRow(5, inComponent:0, animated:false)
        myPickerView.backgroundColor = UIColor.init(white:0.80, alpha:0.80)
        myPickerView.translatesAutoresizingMaskIntoConstraints = false

        self.view.addSubview(myPickerView)
        let margins = self.view.layoutMarginsGuide

        let topC = myPickerView.topAnchor.constraintEqualToAnchor(topLayoutGuide.topAnchor, constant: 100.0)
        let leadingC = myPickerView.leadingAnchor.constraintEqualToAnchor(margins.leadingAnchor)
        let trailingC = myPickerView.trailingAnchor.constraintEqualToAnchor(margins.trailingAnchor)
        let heightC = myPickerView.heightAnchor.constraintEqualToConstant(0.0)
        heightC.identifier = "height"
        NSLayoutConstraint.activateConstraints([topC, leadingC, trailingC, heightC])

        self.view.layoutIfNeeded()
        myPickerView.setNeedsLayout()
        heightC.constant = 162.0

        UIView.animateWithDuration(0.5, delay:0.0, options:UIViewAnimationOptions.CurveEaseInOut, animations:{
            self.view.layoutIfNeeded()
            }, completion: { _ in
        })
    }
    else {
        self.selectPickerView()
    }
}

func selectPickerView(){
    if (activePickerView == myPickerView.tag)
    {
        let _ = myPickerView.selectedRowInComponent(0)

        for constraint in myPickerView.constraints
        {
            if constraint.identifier == "height"
            {   constraint.constant = 0.0   }
        }
        myPickerView.setNeedsLayout()

        UIView.animateWithDuration(0.5, delay:0.0, options:UIViewAnimationOptions.CurveEaseInOut, animations:{
            self.view.layoutIfNeeded()
            }, completion:{ _ in
                self.myPickerView.removeConstraints(self.myPickerView.constraints)
                self.myPickerView.removeFromSuperview()
        })
    }
    activePickerView = 0
}

// MARK: UIPickerViewDataSource methods
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int
{   return 1    }

func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int
{   return 10   }

func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String?
{   return "Row \(row)" }

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    activePickerView = pickerView.tag
    selectPickerView()
}

}

我不喜欢丢弃 pickerView 的动画（我不知道为什么它与显示它的动画不完全相反），但它确实有效。将来我可能会使用不透明视图更改它以覆盖pickerView。