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
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")
}
其他回答
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))
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")
}
在Swift 4.2中编写下面的示例代码,用于以编程方式添加按钮。
override func viewDidLoad() {
super.viewDidLoad()
let myButton = UIButton(frame: CGRect(x: 100, y: 100, width: 100, height: 50))
myButton.backgroundColor = .green
myButton.setTitle("Hello UIButton", for: .normal)
myButton.addTarget(self, action: #selector(myButtonAction), for: .touchUpInside)
self.view.addSubview(myButton)
}
@objc func myButtonAction(sender: UIButton!) {
print("My Button tapped")
}
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
斯威夫特3
let btn = UIButton(type: .custom) as UIButton
btn.backgroundColor = .blue
btn.setTitle("Button", for: .normal)
btn.frame = CGRect(x: 100, y: 100, width: 200, height: 100)
btn.addTarget(self, action: #selector(clickMe), for: .touchUpInside)
self.view.addSubview(btn)
func clickMe(sender:UIButton!) {
print("Button Clicked")
}
输出
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