Target_Action 设计模式

@property (nonatomic, assign)id target;

@property (nonatomic, assign)SEL action;

- (void)viewDidLoad

{

    Button * button =[ [ButtonView  alloc] initWithFrame:CGRectMark(20, 120, 280, 140) ];

    [self.view addSubView: button];

    [button release];

}

button.target = self;

button.action = @select (buttonClicked);