三大常用法寶

本文章著重介紹多線程的基本用法妆艘，本文件的例子是下載圖片為例子殷蛇，子線程下載圖片谱轨，主線程更新圖片

經(jīng)典案例

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    子線程下載任務(wù)
    dispatch_async(dispatch_get_main_queue(), ^{
       主線程更新UI
    });
});

NSThread

//動(dòng)態(tài)創(chuàng)建線程
-(void)dynamicCreateThread{
    NSThread *thread = [[NSThread alloc] initWithTarget:self selector:@selector(loadImageSource:) object:imgUrl];
    thread.threadPriority = 1;// 設(shè)置線程的優(yōu)先級(0.0 - 1.0，1.0最高級)
    [thread start];
}

//靜態(tài)創(chuàng)建線程
-(void)staticCreateThread{
    [NSThread detachNewThreadSelector:@selector(loadImageSource:) toTarget:self withObject:imgUrl];
}

//隱式創(chuàng)建線程
-(void)implicitCreateThread{
    [self performSelectorInBackground:@selector(loadImageSource:) withObject:imgUrl];
}

-(void)loadImageSource:(NSString *)url{
    NSData *imgData = [NSData dataWithContentsOfURL:[NSURL URLWithString:url]];
    UIImage *image = [UIImage imageWithData:imgData];
    if (imgData!=nil) {
        [self performSelectorOnMainThread:@selector(refreshImageView:) withObject:image waitUntilDone:YES];
    }else{
        NSLog(@"there no image data");
    }
}

-(void)refreshImageView:(UIImage *)image{
    [self.loadingLb setHidden:YES];
    [self.imageView setImage:image];
}

NSOperation & NSOperationQueue

//使用子類NSInvocationOperation
-(void)useInvocationOperation{
    NSInvocationOperation *invocationOperation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(loadImageSource:) object:imgUrl];
    //[invocationOperation start];//直接會(huì)在當(dāng)前線程主線程執(zhí)行
    NSOperationQueue *queue = [[NSOperationQueue alloc]init];
    [queue addOperation:invocationOperation];
    
}

//使用子類NSBlockOperation
-(void)useBlockOperation{
    
    NSBlockOperation *blockOperation = [NSBlockOperation blockOperationWithBlock:^{
        [self loadImageSource:imgUrl];
    }];
    
    NSOperationQueue *queue = [[NSOperationQueue alloc]init];
    [queue addOperation:blockOperation];
    
}
//使用繼承NSOperation
-(void)useSubclassOperation{
    
    LoadImageOperation *imageOperation = [LoadImageOperation new];
    imageOperation.loadDelegate = self;
    imageOperation.imgUrl = imgUrl;
    
    NSOperationQueue *queue = [[NSOperationQueue alloc]init];
    [queue addOperation:imageOperation];
}

-(void)loadImageSource:(NSString *)url{
    
    NSData *imgData = [NSData dataWithContentsOfURL:[NSURL URLWithString:url]];
    UIImage *image = [UIImage imageWithData:imgData];
    if (imgData!=nil) {
        [self performSelectorOnMainThread:@selector(refreshImageView1:) withObject:image waitUntilDone:YES];
    }else{
        NSLog(@"there no image data");
    }
    
}

-(void)refreshImageView1:(UIImage *)image{
    [self.loadingLb setHidden:YES];
    [self.imageView setImage:image];
}

Deme鏈接：https://github.com/DuffYang/PerfectMutiThread