ios多线程操作（十）—— 用NSOperation开启多线程操作

NSInvocationOperation *op = [[NSInvocationOperation alloc] initWithTarget:(id) selector:(SEL) object:(id)]

NSInvocationOperation *op = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(downloadImage:) object:@"Invocation"];
   [op start];

- (void)downloadImage:(id)obj {
    NSLog(@"%@ - %@", [NSThread currentThread], obj);
}

// 将操作添加到队列 -> 异步执行 @selector 方法
    NSOperationQueue *q = [[NSOperationQueue alloc] init];
    [q addOperation:op];

NSBlockOperation *op = [NSBlockOperation blockOperationWithBlock:^{
  
        }]

NSOperationQueue *q = [[NSOperationQueue alloc] init];
    
    for (int i = 0; i < 10; ++i) {
        NSInvocationOperation *op = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(downloadImage:) object:@(i)];
       // 将操作添加到队列
        [q addOperation:op];
    }

 NSOperationQueue *q = [[NSOperationQueue alloc] init];
    q.maxConcurrentOperationCount = 2;
    
    for (int i = 0; i < 10; ++i) {
        NSBlockOperation *op = [NSBlockOperation blockOperationWithBlock:^{
            NSLog(@"睡1秒");
            [NSThread sleepForTimeInterval:1.0];
            NSLog(@"%@ - %d", [NSThread currentThread], i);
        }];
        
        [q addOperation:op];
    }

q.maxConcurrentOperationCount = 2;

[self.queue addOperationWithBlock:^{
        NSLog(@"耗时的操作 %@", [NSThread currentThread]);
       
        // 在主线程更新 UI
        [[NSOperationQueue mainQueue] addOperationWithBlock:^{
            NSLog(@"更新 UI %@", [NSThread currentThread]);
        }];
    }];