MAC Day 12 - Objective C - Class

和 C / C++ 不同地方

1. #import
   是當初 C: #include 的改良版, 保證標頭檔只會被匯入一次
   換言之, 標頭檔 就不用寫成像 :

#ifndef _XXX_H_

#define _XXX_H_

...

#endif

   而可以直接宣告

2.  @autoreleasepool

3.  物件

C++:

obj->method(argument);

Objective C:

[obj method: argument];

[ ClassOrInstance method ];

myDog = [Dog new];
[myDog run];


4. Interface

@interface NewClassName : ParentClassName
    propertyAndMethodDeclarations;
@end

@interface MyObject : NSObject 

+(return_type) class_method;            // 類方法
 
-(return_type) instance_method1;        // 實體方法
-(return_type) instance_method2: (int) p1;
-(return_type) instance_method3: (int) p1 andPar: (int) p2;

@end

+: 類似於 C++ : static function

5. Implementation

@implementation NewClassName
{
    memberDeclarations;
}
    methodDefinitions;
@end

@implementation MyObject
{
    int memberVar1; // 實體變數
    id  memberVar2;
}

+(return_type) class_method {
    .... //method implementation
}
-(return_type) instance_method1 {
     ....
}
-(return_type) instance_method2: (int) p1 {
    ....
}
-(return_type) instance_method3: (int) p1 andPar: (int) p2 {
    ....
}
@end

6. NSObject
http://developer.apple.com/library/ios/#documentation/Cocoa/Reference/Foundation/Classes/NSObject_Class/Reference/Reference.html



7. program

@interface Dog: NSObject

-(void) print;

-(void) setName: (NSString*) name;



@end



@implementation Dog 

{

    NSString *name;

}



-(void) print {

    NSLog(@"%@", name);

}



-(void) setName: (NSString*) n {

    name = n;

}

@end





int main(int argc, const char * argv[])

{      

    @autoreleasepool {

        Dog *myDog;

        NSString *name = @"WonWon";

        

        myDog = [Dog new];

        

        [myDog setName: name];

        

        NSLog(@"My dog's name is");

        [myDog print];

        

    }



    return 0;

}