NSOperationQueue *queue = [[NSOperationQueue alloc]init];
NSBlockOperation * operationA = [NSBlockOperation blockOperationWithBlock:^{NSLog(@"operation block A.");
}];
[queue addOperation:operationA];

// 输出// operation block A.

　　NSOperationQueue *queue = [[NSOperationQueue alloc]init];    　　NSBlockOperation * operationA = [NSBlockOperation blockOperationWithBlock:^{NSLog(@"operation block A(1).");}];// 添加[operationA addExecutionBlock:^{NSLog(@"operation block A(2).");}];// 结束block[operationA setCompletionBlock:^{NSLog(@"operation block A compelete.");}];[queue addOperation:operationA];

　　//输出　　2017-01-10 16:26:30.306 IOSTest[74701:3177097] operation block A(1).　　2017-01-10 16:26:30.306 IOSTest[74701:3177217] operation block A(2).　　2017-01-10 16:26:30.308 IOSTest[74701:3177217] operation block A compelete.

　　NSOperationQueue *queue = [[NSOperationQueue alloc]init];    NSBlockOperation * operationA = [NSBlockOperation blockOperationWithBlock:^{NSLog(@"operation block A.");}];NSBlockOperation * operationB = [NSBlockOperation blockOperationWithBlock:^{[NSThread sleepForTimeInterval:1];NSLog(@"operation block B.");}];NSBlockOperation * operationC = [NSBlockOperation blockOperationWithBlock:^{NSLog(@"operation block C.");}];// 依赖
    [operationA addDependency:operationB];[operationA addDependency:operationC];[queue addOperation:operationA];[queue addOperation:operationB];[queue addOperation:operationC];　　　　//输出　　　　2017-01-10 16:41:48.670 IOSTest[74726:3188994] operation block C.　　2017-01-10 16:41:49.670 IOSTest[74726:3188761] operation block B.　　2017-01-10 16:41:49.671 IOSTest[74726:3188761] operation block A

//  NonConcurrentOperation.h
//  IOSTest
//
//  Created by 朱国清 on 17/1/11.
//  Copyright © 2017年 朱国清. All rights reserved.
//

#import <Foundation/Foundation.h>
@interface NonConcurrentOperation : NSOperation
-(instancetype)initWithCalcCount:(NSInteger)calcCount;
@end

//  NonConcurrentOperation.m
//  IOSTest
//
//  Created by 朱国清 on 17/1/11.
//  Copyright © 2017年 朱国清. All rights reserved.
//
#import "NonConcurrentOperation.h"
@interface NonConcurrentOperation()
@property (nonatomic)NSInteger calcCount;
@end
// 同步的任务，只要实现main方法既可，其他状态由NSOperation来控制
@implementation NonConcurrentOperation
-(instancetype)initWithCalcCount:(NSInteger)calcCount{if (self = [super init]) {self.calcCount = calcCount;}return self;
}
// 由start()调用 start是入口，主要作用是更新status和调用main
// 当然调用main前也会先判断一下status
/*void start(){　　　　　//　判断 isCancel 如果已经被cancel了就直接设置isFinished为true，不调用main函数　　　　　// 执行mian 　　　　　[self willChangeValueForKey:@"isFinished"];main();self.isFinished = true;[self didChangeValueForKey:@"isFinished"];}*/
-(void)main{while (!self.cancelled && self.calcCount-- > 0) {[NSThread sleepForTimeInterval:1];NSLog(@"calc[%d]",(int)self.calcCount);}
}
@end

//
//  ConcurrentOperation.h
//  IOSTest
//
//  Created by 朱国清 on 17/1/11.
//  Copyright © 2017年 朱国清. All rights reserved.
//

#import <Foundation/Foundation.h>@interface ConcurrentOperation : NSOperation    @end

//
//  ConcurrentOperation.m
//  IOSTest
//
//  Created by 朱国清 on 17/1/11.
//  Copyright © 2017年 朱国清. All rights reserved.
//

#import "ConcurrentOperation.h"@interface ConcurrentOperation(){BOOL executing;BOOL finished;
}
- (void)completeOperation;
@end@implementation ConcurrentOperation
-(instancetype)init{if (self=[super init]) {executing = NO;finished  = NO;}return self;
}
-(BOOL)isExecuting{return executing;
}
-(BOOL)isFinished{return finished;
}
-(BOOL)isConcurrent{return YES;
}
-(void)start{if (self.cancelled) {// 这样做才能让依赖它的operation知道已经完成了。
        [self completeOperation];return ;}[self willChangeValueForKey:@"isExecuting"];dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{[self main];});executing = YES;[self didChangeValueForKey:@"isExecuting"];
}
-(void)main{NSLog(@"operation start.");[NSThread sleepForTimeInterval:2];NSLog(@"operation end.");[self completeOperation];
}
-(void)completeOperation{[self willChangeValueForKey:@"isFinished"];[self willChangeValueForKey:@"isExecuting"];executing = NO;finished = YES;[self didChangeValueForKey:@"isExecuting"];[self didChangeValueForKey:@"isFinished"];}
@end

　　NSOperationQueue *queue = [[NSOperationQueue alloc]init];NSBlockOperation * operationA = [NSBlockOperation blockOperationWithBlock:^{NSLog(@"operation block A(1).");}];[queue addOperation:operationA];

　　[queue addOperationWithBlock:^{NSLog(@"wrap block .");}];

- (void)addOperations:(NSArray<NSOperation *> *)ops waitUntilFinished:(BOOL)wait

- (void)waitUntilAllOperationsAreFinished

　　- (void)cancelAllOperations

- (BOOL)performOperation:(NSOperation*)anOp
{BOOL        ranIt = NO;// 先判断是否准备好，是否被取消if ([anOp isReady] && ![anOp isCancelled]){　　　　// 串行的话直接运行if (![anOp isConcurrent]){[anOp start];　　　　}　　　　// 并行的话开一个线程else{　      [NSThread detachNewThreadSelector:@selector(start) toTarget:anOp withObject:nil];　　　　}ranIt = YES;}else if ([anOp isCancelled]){// If it was canceled before it was started,//  move the operation to the finished state.[self willChangeValueForKey:@"isFinished"];[self willChangeValueForKey:@"isExecuting"];executing = NO;finished = YES;[self didChangeValueForKey:@"isExecuting"];[self didChangeValueForKey:@"isFinished"];// Set ranIt to YES to prevent the operation from// being passed to this method again in the future.ranIt = YES;}return ranIt;
}