NSOperation和NSOperationQueue的一些基本操作

当初学习多线程这一块的时候，时间比较匆忙，没有细细考虑，而今重新学一次，算是复习和总结吧。

 #import "ViewController.h"

 @interface ViewController ()

 @end

 @implementation ViewController

 /*
  通过调用[self invocationOperation]的log，可以发现，在不加入queue的情况下，默认是在主线程中同步执行操作的

  而通过调用[self blockOperation]的log，可以发现，在不加入queue的情况下，同一个block里的任务是，默认是在主线程中同步执行操作的。但是，如果有多个block操作，会是并发、异步执行的

  NSBlockOperation 可以设置监听，调用[self opeationListen]  在完成任务后，可以设置完成这个任务想要执行的操作

  调用[self operationQueue]的log，可以发现，在不设置依赖的情况下，任务是并发、异步执行的

  而设置依赖的情况下，设置了依赖的任务按照所设定的顺序调用，而没有设置的，则是并发、异步执行
  */
 - (void)viewDidLoad {
     [super viewDidLoad];

     [self opeationListen];
 }

 - (void)invocationOperation
 {
     NSInvocationOperation *invocation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(downLoadImage) object:nil];
     [invocation start];
 }

 - (void)blockOperation
 {
     NSBlockOperation *blockOperation = [[NSBlockOperation alloc] init];

     [blockOperation addExecutionBlock:^{
         for (int i = ; i<; i++) {
             NSLog(@"blockOperation------下载图片1---%@", [NSThread currentThread]);
             [NSThread sleepForTimeInterval:0.1];
         }
     }];

     [blockOperation addExecutionBlock:^{
         NSLog(@"blockOperation__2 --- %@",[NSThread currentThread]);
     }];

     [blockOperation addExecutionBlock:^{
         NSLog(@"blockOperation__3 --- %@",[NSThread currentThread]);
     }];

     [blockOperation start];
 }

 - (void)opeationListen
 {
     NSBlockOperation *blockOperation = [NSBlockOperation blockOperationWithBlock:^{
         for (int i = ; i<; i++) {
             NSLog(@"opeationListen------下载图片---%@", [NSThread currentThread]);
         }
     }];

     blockOperation.completionBlock = ^{
         // ...下载完图片后想做事情
         NSLog(@"NSBlockOperation------下载图片完毕---%@", [NSThread currentThread]);
     };

     [blockOperation start];
 }

 - (void)downLoadImage
 {
     for (int i = ; i < ; i++) {
         NSLog(@"downLoadImage----正在下载----image---%@",[NSThread currentThread]);
         [NSThread sleepForTimeInterval:0.2];
     }
 }

 - (void)run
 {
     for (int i = ; i<; i++) {
         NSLog(@"run---正在跑步-----%@", [NSThread currentThread]);
         [NSThread sleepForTimeInterval:0.2];
     }
 }
 - (void)operationQueue
 {
     NSInvocationOperation *invocationOperation_1 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(downLoadImage) object:nil];

     NSInvocationOperation *invocationOperation_2 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(run) object:nil];

     NSBlockOperation *blockOperation_1 = [NSBlockOperation blockOperationWithBlock:^{
         for (int i = ; i < ; i++) {
             NSLog(@"blockOperation_1------下载图片---%@", [NSThread currentThread]);
             [NSThread sleepForTimeInterval:0.1];
         }
     }];

     NSBlockOperation *blockOperation_2 = [NSBlockOperation blockOperationWithBlock:^{
         for (int i = ; i < ; i++) {
             NSLog(@"blockOperation_2------下载视频---%@", [NSThread currentThread]);
             [NSThread sleepForTimeInterval:0.1];
         }
     }];

     //设置依赖
     [blockOperation_2 addDependency:blockOperation_1];

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

     //设置最大并发数（一般设置为2~~3个）
     queue.maxConcurrentOperationCount = ;

     [queue addOperations:@[invocationOperation_1, invocationOperation_2, blockOperation_1, blockOperation_2] waitUntilFinished:NO];
 }
 @end