iOS Basics (design mode)

A factory approach

The factory method allows us to quickly create a method of an instance of a class. With the factory method, the invocation process can be made clearer.

Person.h

1#import <Foundation/Foundation.h>2 3 @interface Person:nsobject4 {5     int_age;6NSString *_name;7 }8 9- (int) age;Ten-(NSString *) name; One  A+ (NSString *) Personwithage: (int) Age Andname: (NSString *) name; --(ID) Initwithage: (int) Age Andname: (nsstring*) name; -  the@end

Person.m

1#import"Person.h"2 3 @implementation Person4 5- (int) age{6     return_age;7 }8 9-(NSString *) name{Ten     return_name; One } A  -  -+ (NSString *) Personwithage: (int) Age Andname: (NSString *) name{ the         return[Person Alloc]initwithage:age andname:name]; - }; -  --(ID) Initwithage: (int) Age Andname: (NSString *) name{ +Self =[Super init]; -     if(Self! =Nil) { +_age =Age ; A_name =name; at     } -     returnSelf ; - } -  --(NSString *) description{ -     return[NSString stringWithFormat:@"The age of the person is%d, the name is%@", Self.age, Self.name]; in}

Main.h

1#import <Foundation/Foundation.h>2#import"Person.h"3 4 5 intMainintargcConst Char*argv[]) {6     7Person *P1 = [Person personwithage: -Andname:@"Lisi"];8NSLog (@"%@", p1);9     Ten     return 0; One}

Two-agent design mode

Design principle

Some troublesome things do not want to do their own, you can find a person to help, that is, to the agent to do the object.

Design principles

First, you have a proxy object property. Second, it is very clear what agents have. Finally, be sure to decouple.

Implementation scenarios

Define a protocol, in which you declare some methods of communicating with the agent.

has a proxy attribute id<protocol> delegate

Let the agent comply with protocol.

Example: Nanny and child

1. When a object wants to listen to some changes in the B object, it can use the proxy design mode The nanny wants to monitor the baby's change, then the nanny can become the baby's agent, when the baby changes after the nanny can be heard.
2. When a B object occurs, you want to notify a object, you can use the proxy design mode baby to inform the nanny, then you can let the nanny become an agent of the baby, as long as the nanny become an agent of the baby, after the change in the baby can inform the nanny.
3. When object A cannot handle certain behaviors, it wants object B to handle it (making object B a proxy object for object a) the baby can't eat herself or fall asleep, so the babysitter can help. So long as the babysitter becomes an agent for the baby, it can feed the baby and coax him to sleep.

Tri-Delegate Mode

IPeople.h

1 #import <Foundation/Foundation.h> 2  3 @protocol ipeople <NSObject> 4 5 -(int) age; 6 7 -(void) Setage: (int) age; 8 9 -(nsstring*) name; Ten  @end

ManDelegate.h

1 #import <Foundation/Foundation.h>23 @protocol mandelegate <NSObject>4  5 -(void) onagechanged: (int) age; 6 7 @end

Man.h

1#import <Foundation/Foundation.h>2#import"IPeople.h"3#import"ManDelegate.h"4 5@interface man:nsobject<ipeople>6 {7     int_age;8 }9 Ten-(ID) init; One  A- (int) age; -  -- (void) Setage: (int) age; the  --(NSString *) name; -  -@property id<mandelegate>Delegate; +  -@end

Man.m

1#import"Man.h"2 3 @implementation Mans4 5-(ID) init{6Self =[Super init];7     if(self) {8Self.Delegate=Nil;9_age = -;Ten     } One      A     returnSelf ; - } -  the- (int) age{ -     return_age; - } -  +- (void) Setage: (int) age{ -     if(Age! =_age) { +         if(self.)Delegate){ A[Self.DelegateOnagechanged:age]; at         } -     } -      -_age =Age ; - } -  in-(NSString *) name{ -       return @"Lisi"; to } +  -@end

Main.m

1#import <Foundation/Foundation.h>2#import"Man.h"3#import"ManDelegate.h"4 5@interface mainlistener:nsobject<mandelegate>6- (void) Onagechanged: (int) age;7 @end8 9 @implementation MainlistenerTen  One- (void) Onagechanged: (int) age{ ANSLog (@"Age changed, current age is%d", age); - } -  the @end -  - intMainintargcConst Char*argv[]) { -Man *man =[[Man alloc]init]; +    //man.delegate = [[Mainlistener alloc]init]; - [Man setdelegate: [[Mainlistener Alloc]init]]; +      A     //[man setage:20]; at[Man Setage: +]; -      -     return 0; -}

Resources:

Http://www.cnblogs.com/king129/p/4943875.html

iOS Basics (design mode)