如何在Xcode 6中使用Swift以编程方式创建UILabel？
我已经开始在Xcode 6中使用新的“单视图应用程序”，并为此项目选择了Swift。我有我的文件AppDelegate.swift和ViewController.swift，我不知道该怎么做。
答案 0 :(得分：227)
override func viewDidLoad()
{
super.viewDidLoad()
var label = UILabel(frame: CGRectMake(0, 0, 200, 21))
label.center = CGPointMake(160, 284)
label.textAlignment = NSTextAlignment.Center
label.text = "I'm a test label"
self.view.addSubview(label)
}
Swift 3.0+更新：
let label = UILabel(frame: CGRect(x: 0, y: 0, width: 200, height: 21))
label.center = CGPoint(x: 160, y: 285)
label.textAlignment = .center
label.text = "I'm a test label"
self.view.addSubview(label)
答案 1 :(得分：25)
以下是Swift 3的正确代码，其中包含用于教学目的的注释：
override func viewDidLoad()
{
super.viewDidLoad()
// CGRectMake has been deprecated - and should be let, not var
let label = UILabel(frame: CGRect(x: 0, y: 0, width: 200, height: 21))
// you will probably want to set the font (remember to use Dynamic Type!)
label.font = UIFont.preferredFont(forTextStyle: .footnote)
// and set the text color too - remember good contrast
label.textColor = .black
// may not be necessary (e.g., if the width & height match the superview)
// if you do need to center, CGPointMake has been deprecated, so use this
label.center = CGPoint(x: 160, y: 284)
// this changed in Swift 3 (much better, no?)
label.textAlignment = .center
label.text = "I am a test label"
self.view.addSubview(label)
}
答案 2 :(得分：9)
只是添加已经很好的答案，你可能想在你的项目中添加多个标签，这样做所有这些（设置大小，样式等）将是一件痛苦的事。要解决此问题，您可以创建一个单独的UILabel类。
import UIKit
class MyLabel: UILabel {
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
initializeLabel()
}
override init(frame: CGRect) {
super.init(frame: frame)
initializeLabel()
}
func initializeLabel() {
self.textAlignment = .left
self.font = UIFont(name: "Halvetica", size: 17)
self.textColor = UIColor.white
}
}
要使用它，请执行以下操作
import UIKit
class ViewController: UIViewController {
var myLabel: MyLabel()
override func viewDidLoad() {
super.viewDidLoad()
myLabel = MyLabel(frame: CGRect(x: self.view.frame.size.width / 2, y: self.view.frame.size.height / 2, width: 100, height: 20))
self.view.addSubView(myLabel)
}
}
答案 3 :(得分：9)
Swift 4.X和Xcode 10
let lbl = UILabel(frame: CGRect(x: 10, y: 50, width: 230, height: 21))
lbl.textAlignment = .center //For center alignment
lbl.text = "This is my label fdsjhfg sjdg dfgdfgdfjgdjfhg jdfjgdfgdf end..."
lbl.textColor = .white
lbl.backgroundColor = .lightGray//If required
lbl.font = UIFont.systemFont(ofSize: 17)
//To display multiple lines in label
lbl.numberOfLines = 0 //If you want to display only 2 lines replace 0(Zero) with 2.
lbl.lineBreakMode = .byWordWrapping //Word Wrap
// OR
lbl.lineBreakMode = .byCharWrapping //Charactor Wrap
lbl.sizeToFit()//If required
yourView.addSubview(lbl)
如果您的班级中有多个标签，请使用扩展程序添加属性。
//Label 1
let lbl1 = UILabel(frame: CGRect(x: 10, y: 50, width: 230, height: 21))
lbl1.text = "This is my label fdsjhfg sjdg dfgdfgdfjgdjfhg jdfjgdfgdf end..."
lbl1.myLabel()//Call this function from extension to all your labels
view.addSubview(lbl1)
//Label 2
let lbl2 = UILabel(frame: CGRect(x: 10, y: 150, width: 230, height: 21))
lbl2.text = "This is my label fdsjhfg sjdg dfgdfgdfjgdjfhg jdfjgdfgdf end..."
lbl2.myLabel()//Call this function from extension to all your labels
view.addSubview(lbl2)
extension UILabel {
func myLabel() {
textAlignment = .center
textColor = .white
backgroundColor = .lightGray
font = UIFont.systemFont(ofSize: 17)
numberOfLines = 0
lineBreakMode = .byCharWrapping
sizeToFit()
}
}
答案 4 :(得分：7)
您可以使用以下代码创建标签。
var yourLabel: UILabel = UILabel()
yourLabel.frame = CGRectMake(50, 150, 200, 21)
yourLabel.backgroundColor = UIColor.orangeColor()
yourLabel.textColor = UIColor.blackColor()
yourLabel.textAlignment = NSTextAlignment.Center
yourLabel.text = "test label"
self.view.addSubview(yourLabel)
答案 5 :(得分：4)
使用闭包来使用Swift 4将代码分离成更整洁的东西的替代方法：
class theViewController: UIViewController {
/** Create the UILabel */
var theLabel: UILabel = {
let label = UILabel()
label.lineBreakMode = .byWordWrapping
label.textColor = UIColor.white
label.textAlignment = .left
label.numberOfLines = 3
label.font = UIFont(name: "Helvetica-Bold", size: 22)
return label
}()
override func viewDidLoad() {
/** Add theLabel to the ViewControllers view */
view.addSubview(theLabel)
}
override func viewDidLayoutSubviews() {
/* Set the frame when the layout is changed */
theLabel.frame = CGRect(x: 0,
y: 0,
width: view.frame.width - 30,
height: 24)
}
}
注意，只要在VC中使用函数，theLabel的属性仍然可以更改。您只需在闭包内设置各种默认值，并最大限度地减少viewDidLoad()
答案 6 :(得分：3)
另一个代码swift3
let myLabel = UILabel()
myLabel.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
myLabel.center = CGPoint(x: 0, y: 0)
myLabel.textAlignment = .center
myLabel.text = "myLabel!!!!!"
self.view.addSubview(myLabel)
答案 7 :(得分：3)
在UILabel类之外创建viewDidLoad视图，然后使用viewDidLoad方法将该视图添加到您的主视图中。
lazy var myLabel: UILabel = {
let label = UILabel()
label.translatesAutoresizingMaskIntoConstraints = false
label.text = "This is label view."
label.font = UIFont.systemFont(ofSize: 12)
return label
}()
然后将view添加到viewDidLoad()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(myLabel)
// Set its constraint to display it on screen
myLabel.widthAnchor.constraint(equalToConstant: 200).isActive = true
myLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
myLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
}
答案 8 :(得分：2)
快速创建标签
let label = UILabel(frame: CGRect(x: self.view.frame.origin.x, y: self.view.frame.origin.y, width: self.view.frame.size.width, height: 50))
label.textAlignment = .center
label.text = "Hello this my label"
//To set the color
label.backgroundColor = UIColor.white
label.textColor = UIColor.black
//To set the font Dynamic
label.font = UIFont(name: "Helvetica-Regular", size: 20.0)
//To set the system font
label.font = UIFont.systemFont(ofSize: 20.0)
//To display multiple lines
label.numberOfLines = 0
label.lineBreakMode = .byWordWrapping //Wrap the word of label
label.lineBreakMode = .byCharWrapping //Wrap the charactor of label
label.sizeToFit()
self.view.addSubview(label)
答案 9 :(得分：1)
Swift 4.2和Xcode10。在ViewController中的某个位置：
private lazy var debugInfoLabel: UILabel = {
let label = UILabel()
label.textColor = .white
label.translatesAutoresizingMaskIntoConstraints = false
yourView.addSubview(label)
NSLayoutConstraint.activate([
label.centerXAnchor.constraint(equalTo: suggestionView.centerXAnchor),
label.centerYAnchor.constraint(equalTo: suggestionView.centerYAnchor, constant: -100),
label.widthAnchor.constraint(equalToConstant: 120),
label.heightAnchor.constraint(equalToConstant: 50)])
return label
}()
...
使用：
debugInfoLabel.text = debugInfo
答案 10 :(得分：0)
Swift 4.2和Xcode 10 在viewDidLoad之前初始化标签。
x在viewDidLoad中向视图添加标签并应用约束。
lazy var topLeftLabel: UILabel = {
let label = UILabel()
label.translatesAutoresizingMaskIntoConstraints = false
label.text = "TopLeft"
return label
}()
答案 11 :(得分：0)
快速3/4/5的代码
var noDataLbl: UILabel?
noDataLbl = UILabel(frame: CGRect(x: 0, y: self.view.center.y, width: 290, height: 70))
noDataLbl?.textAlignment = .center
noDataLbl?.font = UIFont(name: "Halvetica", size: 18.0)
noDataLbl?.numberOfLines = 0
noDataLbl?.text = "Replace this with your text."
noDataLbl?.lineBreakMode = .byTruncatingTail
view.addSubview(noDataLbl!)
noDataLbl?.isHidden = false
noDataLbl?.center = self.view.center
答案 12 :(得分：-1)
let label = UILabel(frame: CGRect(x: 0, y: 0, width: 200, height: 21))
label.center = CGPoint(x: 160, y: 285)
label.textAlignment = .center
label.text = "My label"
self.view.addSubview(label)
在ViewDidLoad中尝试以上代码