NSOperation 简单使用

//NSOperation 简单使用

self.myQueue = [[NSOperationQueue alloc] init];

- (void)demo
{
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"下载 %@", [NSThread currentThread]);
    }];
    NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"修改 %@", [NSThread currentThread]);
    }];
    NSBlockOperation *op3 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"保存 %@", [NSThread currentThread]);
    }];
    NSBlockOperation *op4 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"更新UI %@", [NSThread currentThread]);
    }];
    
    // 设定执行顺序, Dependency依赖，可能会开多个，但不会太多
    // 依赖关系是可以跨队列的！
    [op2 addDependency:op1];
    [op3 addDependency:op2];
    [op4 addDependency:op3];
    // GCD是串行队列，异步任务，只会开一个线程
    
    [self.myQueue addOperation:op1];
    [self.myQueue addOperation:op2];
    [self.myQueue addOperation:op3];
    // 所有UI的更新需要在主线程上进行
    [[NSOperationQueue mainQueue] addOperation:op4];
    
    // 同时运行两个线程
<pre name="code" class="objc">    // 例如：

// 如果是3G，开3个子线程 // 如果是WIFI，开6个子线程// self.myQueue.maxConcurrentOperationCount = 2; [self.myQueue addOperationWithBlock:^{ NSLog(@"%@ %d", [NSThread currentThread], i); }];}

    // 如果是3G，开3个子线程