iOS NSOperation 异步加载图片 封装NSOperation 代理更新

#import <Foundation/Foundation.h>

@class MYOperation;

@protocol MYOperationDelecate <NSObject>

-(void)operationWithStr:(UIImage*)str;

@end

@interface MYOperation : NSOperation

@property(nonatomic,copy)NSString *imageURL;

@property(nonatomic,weak)id<MYOperationDelecate>delegate;

@end

#import "MYOperation.h"

@implementation MYOperation

//必须实现main方法

-(void)main

{

@autoreleasepool {

//模拟下载图片返回的字符串在主进程中返回到控制器进行跟新操作

UIImage*str=[self downloadImage];

[[NSOperationQueue mainQueue]addOperationWithBlock:^{

if([self.delegate respondsToSelector:@selector(operationWithStr:)])

{

[self.delegate operationWithStr:str];

}

}];

};

}

//模拟下载图片

-(UIImage*)downloadImage

{

NSURL *url=[NSURL URLWithString:self.imageURL];

NSData *data=[NSData dataWithContentsOfURL:url];

UIImage*image=[UIImage imageWithData:data];

return image;

}

@end

//控制器加载代码

#import "ViewController.h"

#import "MYOperation.h"

@interface ViewController ()<MYOperationDelecate>

@property(nonatomic,strong)NSOperationQueue*operation;

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

MYOperation *operation=[[MYOperation alloc]init];

operation.delegate=self;

operation. imageURL=@"www.baidu.com/image";

[self.operation addOperation:operation];

}

-(void)operationWithStr:(UIImage*)str

{

#warning 在这里实现UI界面的更新

NSLog(@"%@,%@",str,[NSThread currentThread]);

}

-(NSOperationQueue *)operation

{

if(!_operation)

{

_operation=[[NSOperationQueue alloc]init];

[_operation setMaxConcurrentOperationCount:6];

}

return _operation;

}

@end