'action:@selector(aMethod:)'这样写方法:

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

这对我很管用。谢谢。KS。

对于Swift 3(更短的代码)

let button = UIButton(type: UIButtonType.custom)
button.frame = CGRect(x: 0, y: 0, width: 200.0, height: 40.0)
button.addTarget(nil, action: #selector(tapButton(_:)), for: UIControlEvents.touchUpInside)
button.tintColor = UIColor.white
button.backgroundColor = UIColor.red
button.setBackgroundImage(UIImage(named: "ImageName"), for: UIControlState.normal)
button.setTitle("MyTitle", for: UIControlState.normal)
button.isEnabled = true

func tapButton(sender: UIButton) {

}

UIButton *buttonName = [UIButton
buttonWithType:UIButtonTypeRoundedRect];
[buttonName addTarget:self 
    action:@selector(aMethod:)forControlEvents:UIControlEventTouchDown];
[buttonName setTitle:@"Show View" forState:UIControlStateNormal];
.frame = CGRectMake(80.0, 210.0, 160.0, 40.0); [view
addSubview:buttonName];

UIButton *custombutton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[custombutton addTarget:self
                 action:@selector(aMethod:)
       forControlEvents:UIControlEventTouchUpInside];
[custombutton setTitle:@"Click" forState:UIControlStateNormal];
custombutton.frame = CGRectMake(80.0, 110.0, 160.0, 40.0);
custombutton.titleLabel.textColor = [UIColor colorWithRed: 2.0f/255.0f green: 155.0f/255.0f blue: 213.0f/255.0f  alpha:1];
 [custombutton setImage:[UIImage imageNamed:@"hh.png"] forState:UIControlStateNormal];
 [view addSubview:custombutton];

Swift 3版本应该是:

let myButton:UIButton = {
    let myButton = UIButton() // If you want to set the type use like
                              // UIButton(type: .RoundedRect) or
                              // UIButton(type: .Custom)
    myButton.setTitle("Hai Touch Me", for: .normal)
    myButton.setTitleColor(UIColor.blue, for: .normal)
    myButton.frame = CGRect(x: 20, y: 20, width: 100, height: 40)

    myButton.addTarget(self, action: #selector(ViewController.pressedAction(_:)), for: .touchUpInside)
    self.view.addSubview(myButton)

    return myButton
}()

UIButton *addProject = [UIButton buttonWithType: UIButtonTypeRoundedRect];
addProject.frame = CGRectMake(210, 285, 100, 18);
[addProject setTitle:@"Show View" forState:UIControlStateNormal];
[addProject addTarget:self action:@selector(addProjectPressed:) forControlEvents:UIControlEventTouchUpInside];
[_scrollView addSubview:addProject];