NSOperationQueue 队列

- (void)viewDidLoad

{

[super viewDidLoad];

}

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

{

NSOperationQueue *queue = [[NSOperationQueue alloc] init];

[queue addOperationWithBlock:^{

// 1.异步下载图片

NSURL *url = [NSURL URLWithString:@"http://d.hiphotos.baidu.com/image/pic/item/37d3d539b6003af3290eaf5d362ac65c1038b652.jpg"];

NSData *data = [NSData dataWithContentsOfURL:url];

UIImage *image = [UIImage imageWithData:data];

// 2.回到主线程，显示图片

// [self performSelectorOnMainThread:<#(SEL)#> withObject:<#(id)#> waitUntilDone:<#(BOOL)#>];

// dispatch_async(dispatch_get_main_queue(), ^{

//

// });

[[NSOperationQueue mainQueue] addOperationWithBlock:^{

self.imageView.image = image;

}];

}];

}

- (void)dependency

{

/**

假设有A、B、C三个操作，要求：

1. 3个操作都异步执行

2. 操作C依赖于操作B

3. 操作B依赖于操作A

*/

// 1.创建一个队列（非主队列）

NSOperationQueue *queue = [[NSOperationQueue alloc] init];

// 2.创建3个操作

NSBlockOperation *operationA = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"A1---%@", [NSThread currentThread]);

}];

// [operationA addExecutionBlock:^{

// NSLog(@"A2---%@", [NSThread currentThread]);

// }];

//

// [operationA setCompletionBlock:^{

// NSLog(@"AAAAA---%@", [NSThread currentThread]);

// }];

NSBlockOperation *operationB = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"B---%@", [NSThread currentThread]);

}];

NSBlockOperation *operationC = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"C---%@", [NSThread currentThread]);

}];

// 设置依赖

[operationB addDependency:operationA];

[operationC addDependency:operationB];

// 3.添加操作到队列中（自动异步执行任务）

[queue addOperation:operationC];

[queue addOperation:operationA];

[queue addOperation:operationB];

}

- (void)maxCount

{

// 1.创建一个队列（非主队列）

NSOperationQueue *queue = [[NSOperationQueue alloc] init];

// 2.设置最大并发(最多同时并发执行3个任务)

queue.maxConcurrentOperationCount = 3;

// 3.添加操作到队列中（自动异步执行任务，并发）

NSBlockOperation *operation1 = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"下载图片1---%@", [NSThread currentThread]);

}];

NSBlockOperation *operation2 = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"下载图片2---%@", [NSThread currentThread]);

}];

NSBlockOperation *operation3 = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"下载图片3---%@", [NSThread currentThread]);

}];

NSBlockOperation *operation4 = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"下载图片4---%@", [NSThread currentThread]);

}];

NSInvocationOperation *operation5 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(download) object:nil];

[queue addOperation:operation1];

[queue addOperation:operation2];

[queue addOperation:operation3];

[queue addOperation:operation4];

[queue addOperation:operation5];

[queue addOperationWithBlock:^{

NSLog(@"下载图片5---%@", [NSThread currentThread]);

}];

[queue addOperationWithBlock:^{

NSLog(@"下载图片6---%@", [NSThread currentThread]);

}];

[queue addOperationWithBlock:^{

NSLog(@"下载图片7---%@", [NSThread currentThread]);

}];

[queue addOperationWithBlock:^{

NSLog(@"下载图片8---%@", [NSThread currentThread]);

}];

[queue addOperationWithBlock:^{

NSLog(@"下载图片9---%@", [NSThread currentThread]);

}];

[queue cancelAllOperations];

}

- (void)didReceiveMemoryWarning

{

[super didReceiveMemoryWarning];

// [queue cancelAllOperations]; // 取消队列中的所有任务（不可恢复）

}

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView

{

// [queue setSuspended:YES]; // 暂停队列中的所有任务

}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate

{

// [queue setSuspended:NO]; // 恢复队列中的所有任务

}

- (void)download

{

NSLog(@"download---%@", [NSThread currentThread]);

}

- (void)baseUse

{

// 1.创建一个队列（非主队列）

NSOperationQueue *queue = [[NSOperationQueue alloc] init];

// 2.添加操作到队列中（自动异步执行任务，并发）

NSBlockOperation *operation1 = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"下载图片1---%@", [NSThread currentThread]);

}];

NSBlockOperation *operation2 = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"下载图片2---%@", [NSThread currentThread]);

}];

[queue addOperation:operation1];

[queue addOperation:operation2];

[queue addOperationWithBlock:^{

NSLog(@"下载图片3---%@", [NSThread currentThread]);

}];

// 3个操作并发执行

}