iOS NSOperation 封裝 通知實現介面更新

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#import <Foundation/Foundation.h>

#import <UIKit/UIKit.h>

@interface MYOperation : NSOperation

@end

 

#import "MYOperation.h"

@implementation MYOperation

-(void)main

{

    //不管是ARC還是MRC一定要用autorelease來釋放c語言對象

    @autoreleasepool {

        //NSString *image=[self stringEith];

        //發布通知

        //[[NSNotificationCenter defaultCenter] postNotificationName:@"MYOperation" object:image];

        [self stringEith];

        

        [self downLoadImage:@"URL"];

    }

    

    

}

//類比下載 跳到主進程類比發送通知,通知控制器更新UI

-(NSString*)stringEith

{

    NSString*image= @"大壞蛋!!!!";

    [[NSOperationQueue mainQueue]addOperationWithBlock:^{

        [[NSNotificationCenter defaultCenter] postNotificationName:@"MYOperation" object:image];

    }];

    return image;

}

//下載

-(UIImage *)downLoadImage:(NSString*)str

{

    NSURL *url=[NSURL URLWithString:str];

    NSData *data=[NSData dataWithContentsOfURL:url];

    UIImage*image=[UIImage imageWithData:data];

    

    [[NSOperationQueue mainQueue]addOperationWithBlock:^{

        [[NSNotificationCenter defaultCenter] postNotificationName:@"MYOperation" object:image];

    }];

    //return image;

    

    return image;

    

}

@end

 

 

//控制器代碼

 

#import "ViewController.h"

 

#import "MYOperation.h"

@interface ViewController ()

@property(nonatomic,strong)NSOperationQueue*queue;

@property(nonatomic,strong)NSString*str;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    

    //發送通知的是在子進程,這裡接收通知執行方法也是在子進程中執行,,發送通知是在主進程,這裡接收通知執行方法也是在主進程中執行,一般情況下更新UI是在主進程中進行,所以這裡我們應該預設讓接收事件方法在主進程中執行\

    需要在拓展類中進行操作

    //註冊通知事件

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateImage:) name:@"MYOperation" object:nil];

    

    

    

}

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

{

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

    //監聽

    [self.queue addOperation:operation];

    

    

    

}

//

-(void)updateImage:(NSNotification*)notification

{

    self.str=notification.object;

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

}

//註冊的通知事件一定要移除

-(void)dealloc

{

    [[NSNotificationCenter defaultCenter]removeObserver:self];

}

-(NSOperationQueue*)queue

{

    if (!_queue) {

        _queue=[[NSOperationQueue alloc]init];

        //設定最大線程數

        [_queue setMaxConcurrentOperationCount:6];

    }

    return _queue;

}

@end

 

iOS NSOperation 封裝 通知實現介面更新