相比GCD NSOperation更加的靈活

1.NSInvocationOperation

創(chuàng)建操作 ---> 創(chuàng)建隊列 ---> 操作加入隊列

    // 處理事務
    NSInvocationOperation *op = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(handleInvocation:) object:@"hello"];

    //如果沒有創(chuàng)建隊列直接啟動事務就在主線程里
    //[op start];

    // 創(chuàng)建隊列
    NSOperationQueue *queue   = [[NSOperationQueue alloc] init];
    // 操作加入隊列
    [queue addOperation:op];
    
    //在這里不可以啟動摘昌，因為已經(jīng)啟動，此時在去啟動就會把一個在running狀態(tài)的隊列重新start 造成線程混亂直接GG  
    //可以用 [[NSOperationQueue mainQueue] addOperation:op];
    //[op start];

2.NSBlockOperation

相比NSInvocationOperation子巾，NSBlockOperation是函數(shù)式編程，代碼可讀性更強

    //1:創(chuàng)建blockOperation
    NSBlockOperation *bo = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"%@",[NSThread currentThread]);
        sleep(3);
    }];
    
    //1.1 添加執(zhí)行代碼塊
    [bo addExecutionBlock:^{
        NSLog(@"這是一個執(zhí)行代碼塊 - %@",[NSThread currentThread]);
    }];
    //1.2 設置監(jiān)聽
    bo.completionBlock = ^{
        NSLog(@"完成了!!!");
    };
    
    //2:創(chuàng)建隊列
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    //3:添加到隊列
    [queue addOperation:bo];
    NSLog(@"事務添加進了NSOperationQueue");

3.優(yōu)先級

- (void)demo{
    // 優(yōu)先級
    NSBlockOperation *bo1 = [NSBlockOperation blockOperationWithBlock:^{
        for (int i = 0; i < 10; i++) {
            NSLog(@"**第一個操作** %d --- %@", i, [NSThread currentThread]);
        }
    }];
    // 設置優(yōu)先級 - 最高
    bo1.qualityOfService = NSQualityOfServiceUserInteractive;
    
    //創(chuàng)建第二個操作
    NSBlockOperation *bo2 = [NSBlockOperation blockOperationWithBlock:^{
        for (int i = 0; i < 10; i++) {
            NSLog(@"第二個操作 %d --- %@", i, [NSThread currentThread]);
        }
    }];
    // 設置優(yōu)先級 - 最低
    bo2.qualityOfService = NSQualityOfServiceBackground;
    
    //2:創(chuàng)建隊列
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    //3:添加到隊列
    [queue addOperation:bo1];
    [queue addOperation:bo2];
    
}

4.線程通訊

- (void)demo {
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    queue.name = @"hello";
    [queue addOperationWithBlock:^{
        NSLog(@"%@ = %@",[NSOperationQueue currentQueue],[NSThread currentThread]);
        //模擬請求網(wǎng)絡
        [[NSOperationQueue mainQueue] addOperationWithBlock:^{
            NSLog(@"%@ --%@",[NSOperationQueue currentQueue],[NSThread currentThread]);
        }];
    }];
}

5.控制并發(fā)量

- (void)demo {
    // 設置并發(fā)數(shù)
    self.queue.name = @"hello";
    self.queue.maxConcurrentOperationCount = 2;
    for (int i = 0; i<10; i++) {
        [self.queue addOperationWithBlock:^{ // 一個任務
            [NSThread sleepForTimeInterval:2];
            NSLog(@"%d-%@",i,[NSThread currentThread]);
        }];
    }
}

6.依賴關系

- (void)demo{
    NSBlockOperation *bo1 = [NSBlockOperation blockOperationWithBlock:^{
        [NSThread sleepForTimeInterval:0.5];
        NSLog(@"請求token");
    }];
    
    NSBlockOperation *bo2 = [NSBlockOperation blockOperationWithBlock:^{
        [NSThread sleepForTimeInterval:0.5];
        NSLog(@"拿著token,請求數(shù)據(jù)1");
    }];
    
    NSBlockOperation *bo3 = [NSBlockOperation blockOperationWithBlock:^{
        [NSThread sleepForTimeInterval:0.5];
        NSLog(@"拿著數(shù)據(jù)1,請求數(shù)據(jù)2");
    }];
    
    // 建立依賴最容易犯的問題就是循環(huán)嵌套
    [bo2 addDependency:bo1];
    [bo3 addDependency:bo2];
    
    //[bo1 addDependency:bo3];

    [self.queue addOperations:@[bo1,bo2,bo3] waitUntilFinished:YES];
    
    NSLog(@"執(zhí)行完了?我要干其他事");
}

7.掛起、繼續(xù)迈螟、取消

正在執(zhí)行的操作無法掛起或者取消
執(zhí)行結果發(fā)現(xiàn),正在執(zhí)行的操作無法取消,因為這要回想到之前的NSThread
只有在內(nèi)部判斷才能取消完畢