试试这个:

首先把它写在你的。h文件的viewcontroller

UIButton *btn;

现在把这个写在viewcontrollers viewDidLoad的。m文件中。

btn=[[UIButton alloc]initWithFrame:CGRectMake(50, 20, 30, 30)];
[btn setBackgroundColor:[UIColor orangeColor]];
[btn setTitle: @"My Button" forState:UIControlStateNormal];
[btn setTitleColor: [UIColor blueVolor] forState:UIControlStateNormal];
[btn.layer setBorderWidth:1.0f];
[btn.layer setBorderColor:[UIColor BlueVolor].CGColor];
//adding action programatically
[btn addTarget:self action:@selector(btnClicked:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:btn];

在视图控制器的。m文件中写入viewDidLoad方法的外部

- (IBAction)btnClicked:(id)sender
{
  //Write a code you want to execute on buttons click event
}

-(void)addStuffToView
{
    UIButton *aButton = [[UIButton alloc] initWithFrame:CGRectMake(20, 20, 20, 20)]; //(x, y, width, height of button on screen
    [aButton setTitle:@"Button" forState:UIControlStateNormal];//puts the text on the button
    aButton.titleLabel.font = somefont;//sets the font if one is already stated
    aButton.titleLabel.font = [UIFont fontWithName:@"Arial-MT" size:12];//sets the font type and size
    [aButton addTarget:self action:@selector(back) forControlEvents:UIControlEventTouchUpInside];//see back method below
    [aButton setBackgroundImage:[UIImage imageNamed:@"someImage.png"] forState:UIControlStateNormal];//sets the image of the button
    [self.view addSubview:back];
}

-(void)back
{
    UIAlertView *alert = [[UIAlertView alloc]initWithTitle.....]
}

-(void)viewDidLoad
{
    [super viewDidLoad];
    [self addStuffToView];//adds all items built in this method to the view
}

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)

UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[button addTarget:self 
           action:@selector(aMethod:)
 forControlEvents:UIControlEventTouchUpInside];
[button setTitle:@"Show View" forState:UIControlStateNormal];
button.frame = CGRectMake(10.0, 100.0, 300.0, 20.0);
[self.view addSubview:button];

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
    }
}

objective - c

// Create the Button with RoundedRect type
UIButton *mybutton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
// instend of "Click Me" you can write your own message/Label
[mybutton setTitle:@"Click Me" forState:UIControlStateNormal];
// create the Rectangle Frame with specified size
mybutton.frame = CGRectMake(10, 10, 300, 140); // x,y,width,height    [self.view addSubview:mybutton];// add button to your view.

斯威夫特

let button   = UIButton(type: UIButtonType.System) as UIButton
button.frame = CGRectMake(100, 100, 100, 50)
button.backgroundColor = UIColor.greenColor()
button.setTitle("Test Button", forState: UIControlState.Normal)
self.view.addSubview(button)