在Swift 5和Xcode 10.2中

基本上我们有两种类型的按钮。

1)系统类型按钮

2)自定义类型按钮(在自定义类型按钮中，我们可以为按钮设置背景图像)

而且这两种类型的按钮控制状态很少https://developer.apple.com/documentation/uikit/uicontrol/state

重要的州有

1)正常状态

2)选定状态

3)高亮状态

4)禁用状态……

//For system type button
let button = UIButton(type: .system)
button.frame = CGRect(x: 100, y: 250, width: 100, height: 50)
//  button.backgroundColor = .blue
button.setTitle("Button", for: .normal)
button.setTitleColor(.white, for: .normal)
button.titleLabel?.font = UIFont.boldSystemFont(ofSize: 13.0)
button.titleLabel?.textAlignment = .center//Text alighment center
button.titleLabel?.numberOfLines = 0//To display multiple lines in UIButton
button.titleLabel?.lineBreakMode = .byWordWrapping//By word wrapping
button.tag = 1//To assign tag value
button.btnProperties()//Call UIButton properties from extension function
button.addTarget(self, action:#selector(self.buttonClicked), for: .touchUpInside)
self.view.addSubview(button)

//For custom type button (add image to your button)
let button2 = UIButton(type: .custom)
button2.frame = CGRect(x: 100, y: 400, width: 100, height: 50)
//        button2.backgroundColor = .blue
button2.setImage(UIImage.init(named: "img.png"), for: .normal)
button2.tag = 2
button2.btnProperties()//Call UIButton properties from extension function
button2.addTarget(self, action:#selector(self.buttonClicked), for: .touchUpInside)
self.view.addSubview(button2)

@objc func buttonClicked(sender:UIButton) {
    print("Button \(sender.tag) clicked")
}

//You can add UIButton properties using extension
extension UIButton {
    func btnProperties() {
        layer.cornerRadius = 10//Set button corner radious
        clipsToBounds = true
        backgroundColor = .blue//Set background colour
        //titleLabel?.textAlignment = .center//add properties like this
    }
}

在这里你可以动态创建一个UIButton:

//For button image
UIImage *closebtnimg = [UIImage imageNamed:@"close_btn.png"];
//Custom type button
btnclose = [[UIButton buttonWithType:UIButtonTypeCustom]retain];
//Set frame of button means position
btnclose.frame = CGRectMake(103, 257, 94, 32);
//Button with 0 border so it's shape like image shape
[btnclose.layer setBorderWidth:0];
//Set title of button
[btnclose setTitle:@"CLOSE" forState:UIControlStateNormal];
[btnclose addTarget:self action:@selector(methodname:) forControlEvents:UIControlEventTouchUpInside];
//Font size of title
btnclose.titleLabel.font = [UIFont boldSystemFontOfSize:14];
//Set image of button
[btnclose setBackgroundImage:closebtnimg forState:UIControlStateNormal];

从Swift 3开始，语法有了一些变化。

以下是如何创建Swift 3的基本按钮:

    let button = UIButton(type: UIButtonType.system) as UIButton
    button.frame = CGRect(x: 100, y: 100, width: 100, height: 50)
    button.backgroundColor = UIColor.green
    button.setTitle("Example Button", for: UIControlState.normal)
    self.view.addSubview(button)

以下是Swift自以前版本以来所做的更改:

let button = UIButton(type: UIButtonType.System) as UIButton

// system no longer capitalised

button.frame = CGRectMake(100, 100, 100, 50)

// CGRectMake has been removed as of Swift 3

button.backgroundColor = UIColor.greenColor()

// greenColor replaced with green

button.setTitle("Example Button", forState: UIControlState.Normal)

// normal is no longer capitalised

self.view.addSubview(button)

拜托，都2014年了!为什么代码块评估分配还没有被使用，因为趋势表明这是未来的趋势!

UIButton* button = ({
    //initialize button with frame
    UIButton* button = [[UIButton alloc] initWithFrame:({
        CGRect frame = CGRectMake(10.0, 10.0, 200.0, 75.0);
        frame;
    })];
    //set button background color
    [button setBackgroundColor:({
        UIColor* color = [UIColor colorWithRed:1.0 green:1.0 blue:0.0 alpha:1.0];
        color;
    })];
    //set button title for state
    [button setTitle:({
        NSString* string = [NSString stringWithFormat:@"title words"];
        string;
    }) forState:({
        UIControlState state = UIControlStateNormal;
        state;
    })];
    //set selector
    [button addTarget:self action:({
        SEL select = @selector(method:);
        select;
    }) forControlEvents:({
        UIControlEvents event = UIControlEventTouchUpInside;
        event;
    })];
    //return button
    button;
});
[self.view addSubview:button];

哇!

或者确切的结果可以这样完成:

UIButton* button = [[UIButton alloc] initWithFrame:CGRectMake(10.0, 10.0, 200.0, 75.0)];
[button setBackgroundColor:[UIColor colorWithRed:1.0 green:1.0 blue:0.0 alpha:1.0]];
[button setTitle:@"title words" forState:UIControlStateNormal];
[button addTarget:self action:@selector(method:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:button];

'action:@selector(aMethod:)'这样写方法:

- (void)aMethod:(UIButton*)button
   {
         NSLog(@"Button  clicked.");
  }

这对我很管用。谢谢。KS。

你可以通过这段代码创建按钮。

 UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
 [btn addTarget:self action:@selector(btnAction) forControlEvents:UIControlEventTouchDragInside];
 [btn setTitle:@"click button" forState:UIControlStateNormal];
  btn.frame = CGRectMake(50, 100, 80, 40);
  [self.view addSubview:btn];

下面是按钮动作方法

 -(void)btnAction
 {
   NSLog(@"button clicked");
 }