我如何以编程方式创建图形元素(如UIButton)在Swift?我试图创建和添加按钮到一个视图,但不能。
当前回答
如何使用Swift 3.0来做到这一点。
func createButton() {
let button = UIButton(type: .system)
button.frame = CGRect(x: 100.0, y: 100.0, width: 100.0, height: 100.0)
button.setTitle(NSLocalizedString("Button", comment: "Button"), for: .normal)
button.backgroundColor = .green
button.addTarget(self, action: #selector(buttonAction(sender:)), for: .touchUpInside)
view.addSubview(button)
}
@objc func buttonAction(sender: UIButton) {
print("Button pushed")
}
其他回答
var sampleButton:UIButton?
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(animated: Bool) {
sampleButton = UIButton(type: .RoundedRect)
//sampleButton.frame = CGRect(x:50, y:500, width:70, height:50)
sampleButton!.setTitle("Sample \n UI Button", forState: .Normal)
sampleButton!.titleLabel?.lineBreakMode = .ByWordWrapping
sampleButton!.titleLabel?.textAlignment = .Center
sampleButton!.setTitleColor(UIColor.whiteColor(), forState: .Normal)
sampleButton!.layer.cornerRadius = 6
sampleButton!.backgroundColor = UIColor.redColor().colorWithAlphaComponent(0.6)
sampleButton?.tintColor = UIColor.brownColor()
//Add padding around text
sampleButton!.titleEdgeInsets = UIEdgeInsetsMake(-10,-10,-10,-10)
sampleButton!.contentEdgeInsets = UIEdgeInsetsMake(5,5,5,5)
//Action set up
sampleButton!.addTarget(self, action: "sampleButtonClicked", forControlEvents: .TouchUpInside)
self.view.addSubview(sampleButton!)
//Button Constraints:
sampleButton!.translatesAutoresizingMaskIntoConstraints = false
//To anchor above the tab bar on the bottom of the screen:
let bottomButtonConstraint = sampleButton!.bottomAnchor.constraintEqualToAnchor(bottomLayoutGuide.topAnchor, constant: -20)
//edge of the screen in InterfaceBuilder:
let margins = view.layoutMarginsGuide
let leadingButtonConstraint = sampleButton!.leadingAnchor.constraintEqualToAnchor(margins.leadingAnchor)
bottomButtonConstraint.active = true
leadingButtonConstraint.active = true
}
func sampleButtonClicked(){
print("sample Button Clicked")
}
API没有改变——只有语法改变了。你可以创建一个UIButton并像这样添加它:
var button = UIButton(frame: CGRectMake(0, 0, 50, 50))
self.view.addSubview(button) // assuming you're in a view controller
下面是一个完整的解决方案,以编程方式添加一个UIButton与targetAction。 斯威夫特2.2
override func viewDidLoad() {
super.viewDidLoad()
let button = UIButton(frame: CGRect(x: 100, y: 100, width: 100, height: 50))
button.backgroundColor = .greenColor()
button.setTitle("Test Button", forState: .Normal)
button.addTarget(self, action: #selector(buttonAction), forControlEvents: .TouchUpInside)
self.view.addSubview(button)
}
func buttonAction(sender: UIButton!) {
print("Button tapped")
}
使用NSLayoutConstraint而不是frame来正确地为每个iPhone屏幕放置按钮可能更好。
Swift 3.1的更新代码:
override func viewDidLoad() {
super.viewDidLoad()
let button = UIButton(frame: CGRect(x: 100, y: 100, width: 100, height: 50))
button.backgroundColor = .green
button.setTitle("Test Button", for: .normal)
button.addTarget(self, action: #selector(buttonAction), for: .touchUpInside)
self.view.addSubview(button)
}
func buttonAction(sender: UIButton!) {
print("Button tapped")
}
Swift 4.2的更新代码:
override func viewDidLoad() {
super.viewDidLoad()
let button = UIButton(frame: CGRect(x: 100, y: 100, width: 100, height: 50))
button.backgroundColor = .green
button.setTitle("Test Button", for: .normal)
button.addTarget(self, action: #selector(buttonAction), for: .touchUpInside)
self.view.addSubview(button)
}
@objc func buttonAction(sender: UIButton!) {
print("Button tapped")
}
如果func buttonAction声明为private或internal,上述方法仍然有效。
func viewDidLoad(){
saveActionButton = UIButton(frame: CGRect(x: self.view.frame.size.width - 60, y: 0, width: 50, height: 50))
self.saveActionButton.backgroundColor = UIColor(red: 76/255, green: 217/255, blue: 100/255, alpha: 0.7)
saveActionButton.addTarget(self, action: #selector(doneAction), for: .touchUpInside)
self.saveActionButton.setTitle("Done", for: .normal)
self.saveActionButton.layer.cornerRadius = self.saveActionButton.frame.size.width / 2
self.saveActionButton.layer.borderColor = UIColor.darkGray.cgColor
self.saveActionButton.layer.borderWidth = 1
self.saveActionButton.center.y = self.view.frame.size.height - 80
self.view.addSubview(saveActionButton)
}
func doneAction(){
print("Write your own logic")
}
这是可能的。除了使用swift语法之外,您几乎可以以相同的方式完成所有操作。例如,你可以用这样的代码创建一个UIButton:
var button: UIButton = UIButton(frame: CGRectMake(0, 0, 100, 100))
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