How to Repeat a Suspend Function in Kotlin with Delays

Learn how to effectively repeat a suspend function in Kotlin with a 10-second delay using simple and clear code examples.
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Introduction

When working with asynchronous programming in Kotlin, you might encounter situations where you need to repeat a suspend function at regular intervals. For instance, you may want to fetch data frequently without blocking the main thread. In this post, we will explore how to construct a simple method to repeat a suspend function after a set delay, specifically with an example using 10 seconds.

Understanding the Problem

The main goal is to create a mechanism where we can call a suspend function, such as fetching an Ethereum price, at defined intervals. The challenge is to handle this efficiently in a coroutine environment without freezing the application.

Solution Breakdown

Let’s dive into creating a Kotlin function that accomplishes this task.

Step 1: Defining the Suspend Function

First, we will define a suspend function that simulates a real-world task. In our case, it will just multiply an integer by 20 after a short delay:

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This function can be used to simulate fetching or calculating the price of Ethereum.

Step 2: Calling the Suspend Function Repeatedly

To repeatedly call this suspend function, we’ll create a function that runs in a coroutine and uses a loop. The loop will allow us to repeat the calls with a delay of 1 second between each repeat as follows:

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Here’s how it works:

runBlocking: This is a coroutine builder that bridges the non-suspending world of regular functions and the suspending world of coroutines.

repeat(5): This loop will execute the enclosed code block 5 times with the index values of 0 to 4.

Step 3: Executing the Main Function

Finally, we set up our main function to trigger the request function.

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When you run the above code, you can expect an output like this:

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Each value printed corresponds to the result of multiplying the index by 20, outputted with a 1-second delay in between.

Important Library Import

To make use of the duration capabilities, ensure to import the following at the beginning of your Kotlin file:

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Conclusion

Now you have a clear understanding of how to repeat a suspend function in Kotlin with a delay. This technique is beneficial when fetching periodic data or executing tasks at intervals. By following these steps, you can adapt this method for various suspend functions based on your application's needs. Happy coding!

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