在不阻塞UI的情况下在For循环中添加延迟 [英] Adding Delay In A For Loop Without Blocking UI

问题描述

在我的用户界面中，点击一个按钮时，它会调用一个for循环，该循环依次执行多个任务.

In my UI, when a button is tapped, it calls a for loop that executes several tasks sequentially.

// For Loop
for (int i = 1; i <= 3; i++)
{
    // Perform Task[i]
}
// Results:
// Task 1
// Task 2
// Task 3

在每个任务之后，我想添加一个用户定义的延迟.例如:

After each task, I would like add a user-defined delay. For example:

// For Loop
for (int i = 1; i <= 3; i++)
{
    // Perform Task[i]
    // Add Delay Here
}

// Results:
//
// Task 1
// Delay 2.5 seconds
//
// Task 2
// Delay 3 seconds
//
// Task 3
// Delay 2 seconds

在iOS中，使用Objective-C，有一种方法可以在for循环中添加此类延迟，请记住:

In iOS, using Objective-C, is there a way to add such delays within a for loop, keeping in mind:

1. 用户界面应保持响应状态.
2. 必须按顺序执行任务.

在for循环上下文中的代码示例将是最有帮助的.谢谢.

A code example within the context of a for loop would be most helpful. Thank you.

推荐答案

此解决方案是否有效?我没有使用dispatch_after，而是使用带有[NSThread sleepForTimeInterval]块的dispatch_async，这使我可以在自定义队列中的任何所需位置放置延迟.

Would this solution work? Instead of using dispatch_after, I use dispatch_async with a [NSThread sleepForTimeInterval] block, which allows me to put a delay anywhere that I need in my custom queue.

dispatch_queue_t myCustomQueue;
myCustomQueue = dispatch_queue_create("com.example.MyQueue", NULL);

dispatch_async(myCustomQueue, ^ {
    NSLog(@"Task1");
});

dispatch_async(myCustomQueue, ^ {
    [NSThread sleepForTimeInterval:2.5];
});

dispatch_async(myCustomQueue, ^ {
    NSLog(@"Task2");
});

dispatch_async(myCustomQueue, ^ {
    [NSThread sleepForTimeInterval:3.0];
});

dispatch_async(myCustomQueue, ^ {
    NSLog(@"Task3");
});

dispatch_async(myCustomQueue, ^ {
    [NSThread sleepForTimeInterval:2.0];
});

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