iOS 之 代理五步骤

在需要传值的页面的.h文件中先声明协议和代理方法(代理方法不唯一，可以多个)、设定一个代理人

#import <UIKit/UIKit.h>

#warning第一步声明协议及代理方法

@protocol ChangeColorDelegate <NSObject>

- (void)changeColor;

@end

@interface AView : UIView

#warning第二步设置代理人

@property (nonatomic, assign)id<ChangeColorDelegate>colorDelegate;

@end

在需要传值的页面的.m文件中

#warning第三步执行代理方法  一定要写在触发方法里面  如果是按钮就写在点击按钮后触发的方法里

//对需要传值的页面的.m文件进行初始化，并且建立一个button，点击button进行代理传值

- (instancetype)initWithFrame:(CGRect)frame

{

    self = [super initWithFrame:frame];

    if (self) {

        

        UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];

        button.frame = CGRectMake(40, 100, 40, 40);

        [button addTarget:self action:@selector(buttonAction:) forControlEvents:UIControlEventTouchUpInside];

        button.backgroundColor = [UIColor yellowColor];

        [self addSubview:button];

    }

    return self;

}

- (void)buttonAction:(UIButton *)button

{

//代理人执行代理方法必须写到所触发的方法里

    [self.colorDelegate changeColor];

}

@end

在被传值的页面的.h文件中先引入需要传值的页面的头文件，签订协议

#import <UIKit/UIKit.h>

#import "AView.h"

#warning 第四步 签订协议

@interface RootViewController : UIViewController <ChangeColorDelegate>

@property (nonatomic, retain) AView *aView;

@end

在被传值的页面的.m文件中指定代理人以及实现代理方法，内存问题不要忘记

#import "RootViewController.h"

@interface RootViewController ()

@end

@implementation RootViewController

- (void)dealloc

{

    [_aView release];

    [super dealloc];

}

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view.

    self.view.backgroundColor = [UIColor lightGrayColor];

    self.aView = [[AView alloc]initWithFrame:CGRectMake(40, 40, 300, 300)];

    self.aView.backgroundColor = [UIColor redColor];

    [self.view addSubview:self.aView];

    [self.aView release];

#warning第五步指定代理人

    self.aView.colorDelegate = self;

}

#warning第六步实现代理方法

- (void)changeColor

{

    NSLog(@"有人点我了, 我要改你里面的东西");

    self.view.backgroundColor = [UIColor colorWithRed:arc4random()%256/255.0 green:arc4random()%256/255.0  blue:arc4random()%256/255.0  alpha:1.0];

    

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

/*

#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {

    // Get the new view controller using [segue destinationViewController].

    // Pass the selected object to the new view controller.

}

*/

@end