每次遇到IOS委托总是说的模棱两可，今天有时间所幸整理下，也借鉴网上的文章来说明：
委托Delegate是协议的一种，通过一种@protocol的方式实现，顾名思义，就是委托他人帮自己去做什么事。也就是当自己做什么事情不方便的时候，就可以建立一个委托，这样就可以委托他人帮自己去实现什么方法。
委托注意事项：
1.委托中需要定义协议@protocol,这个协议可以单独定义成一个文件，但是我们习惯把委托对象放在头文件当中。
2.委托目的两个传值和事件（传值传事件个人认为没什么大区别，传值只不过是传事件方法后面加各参数罢了）
3.委托中定义协议的实例对象，注意属性一般设置为assign而非retain（一般命名为delegate，但假如类中原本有这个属性，换一个名字）
4.被委托类中需要在自身interface中声明协议：<XXXXDelegate>,表示该类要实现XXXDelegate协议中方法（有时不声明页不会出现问题，但是被委托对象委托方法按住option按键跳转无法跳转到协议声明方法当中）
5.委托对象的delegate设置为被委托类对象，两种方法一是被委托对象，一是self本身，写的程序很多都是self。
一、委托传值
Customer.h文件
#import <Foundation/Foundation.h>
@protocol MyDelegate<NSObject>
-(void)buyIphone:(NSString *)iphoneType;
@end
@interface Customer：NSObject
@property(nonatomic,assign)id<MyDelegate>delegate;
-(void)willBuy;
@end
Customer.m文件
#import "Customer.h"
@implementation Customer
@synthesize delegate;
-(void)willBuy{
[delegate buyIphone:@"Iphone5"];
}
@end
Businessman.h
#import <Foundation/Foundation.h>
#import "Customer.h"
@interface Businessman :NSObject<MyDelegate>
@end
Businessman.m文件
#import "Businessman.h"
@implementation Businessman
-(void)buyIphone:(NSString*)iphone{
NSLog(@"There is an iphone store,we have %@",iphoneTyoe);
}
@end
main.m
#import <Foundation/Foundation.h>
#import "Customer.h"
#import "Businessman.h"
int main(int argc,const char *argv[])
{
@autoreleasepool{
Customer *customer = [[Customer alloc]init];
Businessman *businessman = [[Businessman alloc]init];
customer.delegate = businessman;
[customer willBuy];
return 0;
}
}
二、通过委托传事件
下面也是简单说一下这个例子：
委托类：Boss
他要处理起草文件和接电话的任务，但是他本身并不实现这些事件响应的方法，而是通过委托让他的被委托类来实现这些响应方法。
被委托类：Secretary
他受Boss的委托实现起草文件和接电话任务的方法。
下面贴代码：
Boss.h
#import <Foundation/Foundation.h>
@protocol MissionDelegate <NSObject>
-(void)draftDocuments;
-(void)tellPhone;
@end
@interface Boss : NSObject
@property(nonatomic, assign)id<MissionDelegate> delegate;
-(void)manage;
@end
Boss.m
[cpp]
#import "Boss.h"
@implementation Boss
@synthesize delegate = _delegate;
-(void)manage {
[_delegate draftDocuments];
[_delegate tellPhone];
}
@end
Secretary.h
[cpp]
#import <Foundation/Foundation.h>
#import "Boss.h"
@interface Secretary : NSObject <MissionDelegate>
@end
#import <Foundation/Foundation.h>
#import "Boss.h"
@interface Secretary : NSObject <MissionDelegate>
@end
Secretary.m
[cpp]
#import "Secretary.h"
@implementation Secretary
-(void)draftDocuments {
NSLog(@"Secretary draft documents");
}
-(void)tellPhone {
NSLog(@"Secretary tell phone");
}
@end
main.m
[cpp]
#import <Foundation/Foundation.h>
#import "Secretary.h"
#import "Boss.h"
int main(int argc, const char * argv[])
{
@autoreleasepool {
// insert code here...
Boss *boss = [[Boss alloc] init];
Secretary *secretary = [[Secretary alloc] init];
boss.delegate = secretary;
[boss manage];
}
return 0;
}
三、这个例子两个view视图之间传递参数
定义一个MyView类，在这个视图中添加了一个button，button的事件响应他本身不处理，而让被委托类去处理，所以它就是委托类。
在主视图中，添加一个MyView类的实例对象，设置该实例对象的代理为self，所以它就是委托类了。
下面还是贴代码，应该都是很容易看懂的。
MyView.h
[cpp]
#import <UIKit/UIKit.h>
@protocol MyDelegate <NSObject>
-(void)print:(NSString*)viewName;
@end
@interface MyView : UIView
@property(nonatomic,assign)id<MyDelegate> mydelegate;
@end
MyView.m
[cpp]
#import "MyView.h"
@implementation MyView
@synthesize mydelegate = _mydelegate;
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
//代码创建一个button
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[button setTitle:@"Button" forState:UIControlStateNormal];
[button setFrame:CGRectMake(10, 10, 100, 50)];
[button setTintColor:[UIColor blueColor]];
//Target-Action模式 为button指定事件处理对象target为self，事件处理方法为buttonPressed
[button addTarget:self action:@selector(buttonPressed) forControlEvents:UIControlEventTouchUpInside];
[self addSubview:button];
}
return self;
}
//事件处理的响应方法
-(void)buttonPressed{
[_mydelegate print:@"this is a view"];
}
@end
DelegateViewController.h
[cpp]
#import <UIKit/UIKit.h>
#import "MyView.h"
@interface DelegateViewController : UIViewController<MyDelegate>
@end
#import <UIKit/UIKit.h>
#import "MyView.h"
@interface DelegateViewController : UIViewController<MyDelegate>
@end
DelegateViewController.m
[cpp]
#import "DelegateViewController.h"
@interface DelegateViewController ()
@end
@implementation DelegateViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
MyView *myView = [[MyView alloc]initWithFrame:CGRectMake(50, 100, 200, 100)];
[myView setBackgroundColor:[UIColor yellowColor]];
myView.mydelegate = self;
[self.view addSubview:myView];
}
-(void)print:(NSString *)viewName {
NSLog(@"%@",viewName);
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
http://www.2cto.com/kf/201307/229082.html
0 0
