UI_Delegate

点击一个继承UIView的MyButton , 来实现点击MyButton后随机更换背景颜色的功能

• MyButton.h文件

#import <UIKit/UIKit.h>
// 1.声明一份协议
@protocol MyButtonDelegate <NSObject>
- (void)changeColor;
end

@interface MyButton : UIView
// 2.设置代理人的属性
@property(nonatomic, assign)id<MyButtonDelegate>delegate;
@end

• MyButton.m文件

#import "MyButton.h"

@implementation MyButton
 (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
// 3.设置代理人执行的方法
    [self.delegate changeColor];
}

@end

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- MainViewController.m 文件

#import "MainViewController.h"
#import "MyButton.h"
@interface MainViewController ()<MyButtonDelegate>  //4.签协议

@end

@implementation MainViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.




    MyButton *button = [[MyButton alloc]initWithFrame:CGRectMake(100, 100, 100, 40)];
    button.backgroundColor = [UIColor yellowColor];
    [self.view addSubview:button];
    [button release];

 // 5.设置代理人
    button.delegate = self;

}

- (void)changeColor{

    self.view.backgroundColor = [UIColor colorWithRed:arc4random() %256 / 255.0 green:arc4random() %256 / 255.0 blue:arc4random() %256 / 255.0 alpha:1];
}

........
@end