當(dāng)使用暫停、取消任務(wù)時(shí)，需要等到正在執(zhí)行的任務(wù)執(zhí)行完成后，才會(huì)執(zhí)行這個(gè)動(dòng)作。其中取消任務(wù)的動(dòng)作不可逆，取消之后任務(wù)不能重新開啟。具體代碼如下：

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    //當(dāng)self.operationQueue.suspended 為YES時(shí)執(zhí)行任務(wù)，為NO時(shí)暫停任務(wù)
    //每個(gè)任務(wù)都有執(zhí)行狀態(tài)，暫停的時(shí)候正在執(zhí)行的任務(wù)執(zhí)行完，才會(huì)暫停
    self.operationQueue.suspended = !self.operationQueue.suspended;
    
    //取消所有的任務(wù)，正在執(zhí)行的任務(wù)執(zhí)行完，才會(huì)執(zhí)行這個(gè)動(dòng)作，和暫停類似。該方法不可逆，取消后不能恢復(fù)執(zhí)行
//    [self.operationQueue  cancelAllOperations];
}


//NSOperationQueue，最大并發(fā)數(shù)
- (void)operationQueueMaxConcurrentOperationCount
{
    //1:創(chuàng)建隊(duì)列
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    /*
     默認(rèn)是并發(fā)隊(duì)列，如果最大并發(fā)數(shù)>1，并發(fā)
     如果最大并發(fā)數(shù)==1，串行
     系統(tǒng)默認(rèn)的并發(fā)數(shù)是-1，所有任務(wù)全部并發(fā)執(zhí)行
     */
    queue.maxConcurrentOperationCount = 1;
    //2:封裝操作
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        [NSThread sleepForTimeInterval:1.0];
        NSLog(@"1------%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{
        [NSThread sleepForTimeInterval:1.0];
        NSLog(@"2------%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op3 = [NSBlockOperation blockOperationWithBlock:^{
        [NSThread sleepForTimeInterval:1.0];
        NSLog(@"3------%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op4 = [NSBlockOperation blockOperationWithBlock:^{
        [NSThread sleepForTimeInterval:1.0];
        NSLog(@"4------%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op5 = [NSBlockOperation blockOperationWithBlock:^{
        [NSThread sleepForTimeInterval:1.0];
        NSLog(@"5------%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op6 = [NSBlockOperation blockOperationWithBlock:^{
        [NSThread sleepForTimeInterval:1.0];
        NSLog(@"6------%@",[NSThread currentThread]);
    }];
    
    //3:把操作添加到隊(duì)列
    [queue addOperation:op1];
    [queue addOperation:op2];
    [queue addOperation:op3];
    [queue addOperation:op4];
    [queue addOperation:op5];
    [queue addOperation:op6];
    self.operationQueue = queue;
}