NSOperation的简单使用代码

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注意点：需要将operation对象添加到队列中。代码：

NSOperationQueue * queue = [NSOperationQueue alloc init];

NSBlockOperation * o1 = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"1---%@", NSThread currentThread);

NSLog(@"1.1---%@", NSThread currentThread);

NSLog(@"1.2---%@", NSThread currentThread);

NSLog(@"1.3---%@", NSThread currentThread);

NSLog(@"1.4---%@", NSThread currentThread);

    }];

NSBlockOperation * o2 = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"2---%@", NSThread currentThread);

    }];

NSBlockOperation * o3 = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"3---%@", NSThread currentThread);

    }];

    o3 addDependency:o1;  // 线程依赖

    o3 addDependency:o2;    // 线程间不能相互依赖

NSMutableArray * arr = NSMutableArray array;

    arr addObject:o1;

    arr addObject:o2;

    arr addObject:o3;

//    queue addOperations:arr waitUntilFinished:YES;

    queue addOperation:o1;

    queue addOperation:o2;

    queue addOperation:o3;

NSLog(@"======================");

// 如何监听所有的任务全部完成

    [queue addOperationWithBlock:^{

NSLog(@"子线程%@", NSThread currentThread);

// 回到主线程

        [NSOperationQueue mainQueue addOperationWithBlock:^{

NSLog(@"回到主线程%@", NSThread currentThread);

        }];

    }];