Handling Change in EditText without Crashing the App in Android Kotlin

Описание: Learn how to prevent crashes in your Android app when a user clears an EditText field by properly handling text changes using addTextChangedListener in Kotlin.
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This video is based on the question https://stackoverflow.com/q/70135880/ asked by the user 'francisRH' ( https://stackoverflow.com/u/17293386/ ) and on the answer https://stackoverflow.com/a/70136597/ provided by the user 'yan sam' ( https://stackoverflow.com/u/13187633/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Handling Change in EditText without Crashing the App in Android Kotlin

When developing applications in Android, especially those requiring user input, you may encounter challenges when handling text input dynamically. One such problem arises when users attempt to change a value entered into an EditText field. In this post, we’ll explore how to prevent application crashes due to NumberFormatException when users clear the field.

The Problem

Imagine a scenario where your app features an EditText for users to input a number. Here’s the sequence of events:

Users enter a number in the EditText and the app behaves as expected.

If they wish to change their input, they must clear the existing number.

Upon clearing, an exception occurs: java.lang.NumberFormatException: For input string: "".

This problem arises because once the text is removed, it sends an empty string to your logic, causing the app to crash when you attempt to convert that empty string into an integer.

The Solution

To handle the empty string case and prevent crashes, we can add checks in the afterTextChanged function of the TextWatcher interface we've applied to our EditText.

Step 1: Modify afterTextChanged

Here’s how to implement a check to ensure that the input is not blank before attempting any conversion:

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

In this modification:

We first check if p0 (the input text) is not blank using isNotBlank().

Only if the string is valid (i.e., not blank), do we proceed to convert it to an integer and execute the subsequent game logic.

Step 2: Alternative Approach

If you prefer a more compact approach, you can use Kotlin's takeIf function to handle this more succinctly. Here’s what that looks like:

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

In this method:

The takeIf function checks if the string is not blank.

If it is blank, it defaults a to 0, avoiding any exception and allowing your game to continue running smoothly.

Summary of Key Points

Always check for empty strings before converting them to numeric types.

Utilize isNotBlank() for readability and better logic flow.

Consider using takeIf for concise and elegant code.

Conclusion

By implementing these checks in your EditText handling code, you can ensure that your Android app remains stable and user-friendly even when the input changes. No more crashes when users try to modify their input!

Happy coding!