How to Fix java.lang.NumberFormatException: multiple points in Android's KeyboardType.Decimal

Struggling with the `multiple points` exception in Android's decimal text inputs? Discover a solution to limit decimal points in your Composable `OutlinedTextField`.
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Imagine the following scenario: you have an OutlinedTextField in your app with the keyboard set to accept decimal numbers. However, when users type something like "2.5.8", your app throws a dreaded multiple points exception on conversion attempts. This can lead to a poor user experience. Thankfully, there's a practical solution!

The Problem: Allowing Multiple Decimals

By default, if you set the keyboardType to KeyboardType.Decimal, the user can input as many decimal points as they wish. Issues arise during conversion when more than one decimal point is detected, leading to runtime exceptions.

The Root Cause

Differences in Decimal Representation: Various device locales can yield different decimal separators. Simply comparing against a '.' might not be a reliable solution.

The Solution: Restricting Decimal Input

To prevent this issue from recurring, you can implement logic that allows only one decimal point in your text input. Here's a step-by-step breakdown of the solution.

Step 1: Get the Device's Decimal Separator

First, you need to identify the decimal separator for the user's locale. This ensures that your app behaves correctly across various regions.

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Use onValueChange to Limit Input

In your TextField component, you can implement the onValueChange lambda function. This function will monitor the user's input and enforce the restriction on the decimal count.

Sample Implementation

Below is an example of how to achieve this with a TextField:

[[See Video to Reveal this Text or Code Snippet]]

In the above code:

State Management: text is a mutable state that holds the value of the TextField.

Input Handling: Each time onValueChange is triggered, it counts the occurrences of the decimal separator. If there's one or fewer, it updates the state.

Conclusion

If you're developing a Kotlin-based Android app using Jetpack Compose and want to offer a smooth user experience regarding numeric input, this approach is essential!

Ensure to test your implementation thoroughly across various locales to further guarantee consistent behavior.

Happy coding!