【Lession 12 OC語言】- 內存管理3 -autorelease

本節目錄

• autorelease
• 靜態建立實例　

 

autorelease

添加了autorelease後就不用再用release代碼，它會本身釋放

#import <Foundation/Foundation.h>
#import "Book.h"
#import "Student.h"

int main(int argc, const char * argv[])
{
    @autoreleasepool {
        
        Book *book = [[[Book alloc] init] autorelease];
        
      }
    return 0;
}

能夠看到程序運行結束會Book被銷燬

2014-03-18 18:11:20.808 HellowWord_OC[1499:303] Book 被銷燬

 

若是沒有再auorelease,Book被銷燬不會被打印出來，說明這個對象沒有被銷燬

 

靜態建立實例

Book.h

#import <Foundation/Foundation.h>

@interface Book : NSObject

@property(nonatomic,assign)double price;

+(id )book;

+(id)bookWithPrice:(double)price;

@end

Book.m

#import "Book.h"

@implementation Book

+(id)book{
    return [[[Book alloc] init] autorelease];
}


+(id)bookWithPrice:(double)price{
    //Book *book = [[[Book alloc] init] autorelease];
    //Book *book = [self book];self指類名
    Book *book = [Book book];
    book.price = price;
    return book;
}

-(void)dealloc{
    NSLog(@"Book 被銷燬");
    [super dealloc];
}

 

猜下有幾個銷燬代碼？

#import <Foundation/Foundation.h>
#import "Book.h"
#import "Student.h"

int main(int argc, const char * argv[])
{
    @autoreleasepool {
        
        Book *book = [[[Book alloc] init] autorelease];
       
        //自定釋放，不用添加relase代碼
        Book *book1 = [Book book];
        
        //自定釋放，不用添加relase代碼
        Book *book2 = [Book bookWithPrice:12.50];
        
        Book *book3 = [[Book alloc] init];
        
      }
    return 0;
}

 

總結：實例化對象時，是用alloc的方法的就要進行添加autorealese或者release代碼

　　　經過靜態方法實例化的不用添加autorealese或者release代碼