NSOperationQueue

NSOperationQueue 队列 包含了 主队列 和 非主队列

    //创建主队列
    NSOperationQueue * mainQueue = [NSOperationQueue mainQueue];
    //创建非主队列
    NSOperationQueue * otherQueue = [[NSOperationQueue alloc] init];

 NSBlockOperation * opOne = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"线程 ------%@",[NSThread currentThread]);
        NSLog(@"一号开始执行");
        
    }];
    [opOne addExecutionBlock:^{
        NSLog(@"线程1 ------%@",[NSThread currentThread]);
        NSLog(@"二号开始执行");
    }];
    
    [opOne addExecutionBlock:^{
        NSLog(@"线程3 ------%@",[NSThread currentThread]);
        NSLog(@"三号开始执行");
    }];
    
    //创建非主队列
    NSOperationQueue * otherQueue = [[NSOperationQueue alloc] init];
    
    [otherQueue addOperation:opOne];

线程1 ------<NSThread: 0x600000318fc0>{number = 4, name = (null)}
线程 ------<NSThread: 0x60000032f2c0>{number = 3, name = (null)}
线程3 ------<NSThread: 0x60000032f240>{number = 5, name = (null)}
三号开始执行
二号开始执行
一号开始执行

可以看出任务开始并发执行

任务依赖

NSInvocationOperation * op = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(invocation) object:nil];

 NSBlockOperation * opOne = [NSBlockOperation blockOperationWithBlock:^{
        sleep(5);
        NSLog(@"1结束了");
        
    }];
   
NSBlockOperation * opTwo = [NSBlockOperation blockOperationWithBlock:^{
        sleep(5);
        NSLog(@"2结束了");
        
    }];

NSOperationQueue * otherQueue = [[NSOperationQueue alloc] init];
    otherQueue.maxConcurrentOperationCount = 1; //设置1 串行执行  大于1 并发执行   默认-1 不限制
    op.queuePriority = NSOperationQueuePriorityVeryHigh;
    [op addDependency:opOne];
    [opTwo addDependency:op];
    [otherQueue addOperation:opOne];
    [otherQueue addOperation:op];
    [otherQueue addOperation: opTwo];

-(void)invocation {
    NSLog(@"线程4 ------%@",[NSThread currentThread]);
    NSLog(@"任务结束了");
}

1结束了
线程4 ------<NSThread: 0x60000299b0c0>{number = 3, name = (null)}
任务结束了
2结束了