ios 在 CGRectMake、Swift、UIkit 中使用变量
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Using variables in CGRectMake, Swift, UIkit
提问by Mats
For an App I'm making i need to use variables to change the size and position of objects (Labels). I've tried var example = CGRectMake(0, 0, 0, 100), hoping it would ignore the zeros (Not really thinking it would though). I then tried:
对于我正在制作的应用程序，我需要使用变量来更改对象（标签）的大小和位置。我试过var example = CGRectMake(0, 0, 0, 100)，希望它会忽略零（不是真的想它会虽然）。然后我尝试：
var example = 100
Label1.frame = CGRectMake(20, 20, 50, example)
I changed the syntax a bit, adding "" and replacing the CGRectMakewith CGRectetc, but nothing worked... I don't get what I'm doing wrong here... Help!
我改变了语法了一下，加上“”和更换CGRectMake用CGRect等，但是毫无效果......我不明白我在做什么错在这里...帮助！
采纳答案by Aaron Rasmussen
CGRectMaketakes CGFloats for all of its arguments. Your sample code should work fine if you specify that exampleis supposed to be a CGFloat, using a type identifier:
CGRectMake将CGFloats 作为其所有参数。如果您使用类型标识符指定example应该是 a CGFloat，您的示例代码应该可以正常工作：
// v~~~~ add this...
var example: CGFloat = 100
Label1.frame = CGRectMake(20, 20, 50, example)
Otherwise, swift infers the type of exampleto be Int, and the call to CGRectMakefails, cuz it can't take an Intas a parameter...
否则，swift 会推断出exampleto的类型Int，并且调用CGRectMake失败，因为它不能将 anInt作为参数......
回答by quemeful
Swift 3 update
斯威夫特 3 更新
let rect = CGRect(x: 0, y: 0, width: 100, height: 100)
回答by Chris
So, there is many ways to skin the cat. It all depends what your needs and requirements are (maybe you could elaborate a bit on what you are trying to achieve?). But one way to do it could be to set a variable when something happens, and then update the frame of the label. If you added a tap gesture recognizer to your view, and updated your label like so:
所以，有很多方法可以给猫剥皮。这完全取决于您的需求和要求是什么（也许您可以详细说明您要实现的目标？）。但一种方法是在发生某些事情时设置一个变量，然后更新标签的框架。如果你在你的视图中添加了一个点击手势识别器，并像这样更新你的标签：
let myLabel = UILabel()
override func viewDidLoad() {
super.viewDidLoad()
let tapGestRecog = UITapGestureRecognizer(target: self, action: "handleTap:")
self.view.addGestureRecognizer(tapGestRecog)
}
func handleTap(sender:UIGestureRecognizer) {
let newXposition = sender.locationInView(self.view).x
let newYposition = sender.locationInView(self.view).y
myLabel.frame = CGRectMake(newXposition, newYposition, 200, 200)
}
This is just an example, and a very crude way of doing it. There are many other ways of doing it, but it hopefully gives you an idea of how to achieve it.
这只是一个例子，而且是一种非常粗略的做法。有很多其他方法可以做到这一点，但希望它能让您了解如何实现它。
回答by Duncan C
Swift allows syntax that Objective-C does not:
Swift 允许使用 Objective-C 不允许的语法：
var example = 100
label.frame.size.height = example
In objective-C you would have to do it differently:
在 Objective-C 中，您必须以不同的方式执行此操作：
CGRect frame = label.frame; //Create a temporary rect to hold the frame value
frame.size.height = example;
label.frame = frame;
