添加 UIImage 忽略并调整 UIImageView 框架的大小 [英] Adding UIImage ignores and resizes UIImageView frame

问题描述

我目前正在尝试将图像添加到一个视图的导航项中.在视图的viewDidLoad()中，调用了一个函数，代码如下，类似于

从 UIImageView 中移除 UIImage 会使视图大小正确，如下所示:

这对我来说似乎很奇怪，尤其是因为我确实将内容模式设置为 .scaleAspectFit.关于将 UIImageView 添加为 navigationItem.titleView，我是否忘记了什么?

解决方案

在 UINavigationBar 上，如果内容很大，标题视图将显示其完整大小.

<块引用>

调整图像大小而不是 UIImageView 如下，传递大小 (122, 26).这将解决您的问题.

func imageResize(sizeChange: CGSize) ->用户界面{让 hasAlpha = truelet scale: CGFloat = 0.0//使用主屏幕的比例因子UIGraphicsBeginImageContextWithOptions(sizeChange, !hasAlpha, scale)self.draw(in: CGRect(origin: CGPoint.zero, size: sizeChange))让 scaledImage = UIGraphicsGetImageFromCurrentImageContext()返回缩放图像！}

I'm currently trying to add an image into the navigation item for one view. In the view's viewDidLoad(), a function is called with the following code, similar to this post:

let logo = UIImage(named: "Menu_Logo")

let imageView = UIImageView(frame: CGRect(x: 0, y: 0, width: 122, height: 26))
imageView.contentMode = .scaleAspectFit
imageView.clipsToBounds = true
imageView.image = logo

self.navigationItem.titleView = imageView

Instead of giving me the expected size however, the view ends up looking like this:

Removing the UIImage from the UIImageView makes the view sized correctly like this:

This seems like strange behaviour to me, especially since I did set the content mode to .scaleAspectFit. Is there something I am forgetting regarding adding an UIImageView as the navigationItem.titleView?

解决方案

On UINavigationBar, title view takes its full size, if content is large.

Resize the image rather than UIImageView as following with passing size (122, 26). This will solve your problem.

func imageResize(sizeChange: CGSize) -> UIImage {
    let hasAlpha = true
    let scale: CGFloat = 0.0 // Use scale factor of main screen

    UIGraphicsBeginImageContextWithOptions(sizeChange, !hasAlpha, scale)
    self.draw(in: CGRect(origin: CGPoint.zero, size: sizeChange))

    let scaledImage = UIGraphicsGetImageFromCurrentImageContext()
    return scaledImage!
}

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