问题描述
我试图将 UIImageView
水平放置在屏幕的上中心,这是在 viewDidLoad( )
中编码的.而且我有两个预先计划,这意味着我不知道指定的函数或 API.
I am trying to put an UIImageView
on the upper center of screen horizontally which is coding in the viewDidLoad( )
. And I have two pre-plans, which means I do not know the specify functions or APIs.
1).我想设置一个等于屏幕宽度一半的变量.而且我知道它会与边界"或框架"有关.可悲的是,我不知道那些指定函数或参数.
1). I want to set a variable which equal to the half of screen's width. And I know it gonna work with something about 'bounds' or 'frame'. Pathetically, I do not know those specify function or parameters.
2).为了确定分辨率,我想找出currentDevice
.之后,我可以使用 CGRectMake((resolution.x)/2, y, length, width)
设置 UIImageView
.有没有什么函数可以确认currentDevice
?
2). In order to make sure the resolution, I want to figure out the currentDevice
. After that, I can set UIImageView
with CGRectMake((resolution.x)/2, y, length, width)
. Is there any function can confirm the currentDevice
?
而且我认为第一个比第二个更有效率.
And I think the first one is more efficient than the second one.
非常感谢您的帮助和指导.
A big appreciate for your help and guidance.
伊桑·乔
推荐答案
我建议使用自动布局:
var imageView = UIImageView()
imageView.setTranslatesAutoresizingMaskIntoConstraints(false)
view.addSubview(imageView)
// Create the constraints and add them to a Array
var constraints = [AnyObject]()
// This constraint centers the imageView Horizontally in the screen
constraints.append(NSLayoutConstraint(item: imageView, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.CenterX, multiplier: 1.0, constant: 0.0))
// Now we need to put the imageView at the top margin of the view
constraints.append(NSLayoutConstraint(item: imageView, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.TopMargin, multiplier: 1.0, constant: 0.0))
// You should also set some constraint about the height of the imageView
// or attach it to some item placed right under it in the view such as the
// BottomMargin of the parent view or another object's Top attribute.
// As example, I set the height to 500.
constraints.append(NSLayoutConstraint(item: imageView, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1.0, constant: 500.0))
// The next line is to activate the constraints saved in the array
NSLayoutConstraint.activateConstraints(constraints)
此代码将每个设备中的 imageView 水平居中.我建议你研究一下 AutoLayout,这是一个不错的功能.
This code horizontally centers the imageView in every device. I suggest you investigating AutoLayout, it's a nice feature.
这是一个很好的链接,您可以从这里开始:学习喜欢自动布局......以编程方式
Here's a nice link where you can start with it:Learning to love Auto Layout... Programmatically
这篇关于如何使用 Swift 在屏幕中心水平或垂直设置 UIImageView,但不再有 StoryBoard的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!