我在 Swift故事板中全屏使用’Aspect Fit’模式imageview.实际图像很好地保持比例.问题是我无法在运行时获得实际的图像宽度/高度.

当我使用imageview.frame.size.width时,它会按预期返回整个屏幕宽度.当我使用image.size.width时,它返回固定的图像宽度(实际图像宽度).但我的目的是获取UI中显示的运行时图像宽度.

如何从源头找到它.

编辑1

当前的肖像画面,中间有标签

当前景观屏幕中间有标签.标签宽度与imageview相同,但不是当前显示的图像宽度.

请尝试以下代码.它完全符合您对iPhone 6S设备的要求.当设备屏幕方向更改为横向模式时,我正在计算标签框架的x位置和宽度.对于5S和4S等其他设备,您需要根据设备高度宽度比计算x位置和宽度.例如,我使用了一些常量值,如9和18.如果要为不同的设备使用代码,则需要使用比率因子.希望这有帮助！

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var theImageView: UIImageView!
@IBOutlet weak var theLabel: UILabel!

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view,typically from a nib.
    theLabel.frame.size.width = (theImageView.image?.size.width)!

    NSNotificationCenter.defaultCenter().addobserver(self,selector: "rotated",name: UIDeviceOrientationDidChangeNotification,object: nil)
}

override func viewDidAppear(animated: Bool) {

    if(UIDeviceOrientationIsLandscape(UIDevice.currentDevice().orientation))
    {
        if (theImageView.image?.size.height)! > (theImageView.image?.size.width)! {
            theLabel.frame.origin.x = (view.frame.size.width - (theImageView.image?.size.height)!)/2
            theLabel.frame.size.width = (theImageView.image?.size.height)!
        }
        else {
            theLabel.frame.origin.x = ((theImageView.image?.size.height)!/2) - 9
            theLabel.frame.size.width = rint(view.frame.size.width) - (theImageView.image?.size.height)! + 18
        }
    }

    if(UIDeviceOrientationIsPortrait(UIDevice.currentDevice().orientation))
    {
        theLabel.frame.size.width = theImageView.frame.size.width
    }
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // dispose of any resources that can be recreated.
}

override func viewWillTransitionToSize(size: CGSize,withTransitionCoordinator coordinator: UIViewControllerTransitionCoordinator) {
    //theImageView.frame.size.width = (theImageView.image?.size.width)!
    //theImageView.frame.size.height = (theImageView.image?.size.height)!
}

func rotated()
{
    if(UIDeviceOrientationIsLandscape(UIDevice.currentDevice().orientation))
    {
        if (theImageView.image?.size.height)! > (theImageView.image?.size.width)! {
            theLabel.frame.origin.x = (view.frame.size.width - (theImageView.image?.size.height)!)/2
            theLabel.frame.size.width = (theImageView.image?.size.height)!
        }
        else {
            theLabel.frame.origin.x = ((theImageView.image?.size.height)!/2) - 9
            theLabel.frame.size.width = rint(view.frame.size.width) - (theImageView.image?.size.height)! + 18
        }
    }

    if(UIDeviceOrientationIsPortrait(UIDevice.currentDevice().orientation))
    {
        theLabel.frame.size.width = theImageView.frame.size.width
    }


}

我有一个这样的元组数组：

var answers: [(number: Int,good: Bool)]

我想从它得到一个数字的成员数组.就像我做了一样的事情：

answers["number"] // -> Should give [Int] of all values named "number"

我没有找到任何类似的东西,也许这是不可能的,但这将是悲伤:(

很简单：

answers.map { $0.number }

在String,Int等类型的数组中找到一个元素非常简单.

var States = ["CA","FL","MI"]
var filteredStates = States.filter {$0 == "FL"} // returns false,true,false

现在,我创建了一个结构体

struct Candy{
    let name:String
}

然后初始化它

var candies =  [Candy(name: "Chocolate"),Candy(name: "Lollipop"),Candy(name: "Caramel")]

任何人都可以建议在包含结构元素的数组中找到“巧克力”的正确方法？我无法实现查找或过滤方法.

使用以下代码,您将收到数组中的所有糖果结构,它们与“巧克力”匹配.

var candiesFiltered = candies.filter{$0.name == "Chocolate"}

如果您只想要一个布尔值(如果已经找到),您可以使用以下代码：

var found = candies.filter{$0.name == "Chocolate"}.count > 0