Best Practices for Error Handling on Mobile Devices

Why You Should Avoid Modal Dialogs for Errors

Content Accessibility

• Transient Nature: Once a modal dialog is dismissed, the information it contained is no longer visible. This makes it difficult for users to refer back to the error message and understand how to correct their mistake.

• Recall vs. Recognition: Users need to remember the instructions provided in the modal, which violates the usability principle favoring recognition over recall. Recalling detailed instructions is especially challenging on mobile devices where interruptions are common.
  
  

User Frustration

• Interruptions: On mobile devices, users are more likely to be interrupted. If they look away or get distracted, they might forget the error details, leading to frustration and repeated mistakes.

• Complexity: Error messages often contain multiple requirements. Remembering all these details after dismissing the modal is difficult, increasing the cognitive load on the user.
  
  

Poor Error Handling Example

Consider a mobile app with a login wall that requires users to create an account. If the app displays an error like "Invalid password. Your password needs to be at least eight characters including a lowercase letter, an uppercase letter, a number, and a special character" in a modal dialog, users face several issues:

• They must dismiss the dialog to correct the error.

• The error message is no longer visible once the dialog is dismissed.

• Users might not remember all the password requirements, leading to repeated errors.
  
  

Effective Error Handling on Mobile Devices

Inline Error Messages

• Immediate Feedback: Display error messages directly next to the relevant form fields. This approach ensures that users can see the error message while they are correcting their input.

• Highlight Fields: Clearly mark the fields with errors to draw users’ attention to the areas that need correction.
  
  

Persistent Visibility

• Keep Error Messages Visible: Ensure that error messages remain visible until the error is corrected. This persistence helps users refer back to the instructions as needed.
  

Clear Instructions

• Detailed Guidance: Provide clear and concise instructions on how to correct the error. Avoid overly complex language and ensure the instructions are easy to follow.
  

Example Implementation

Instead of using a modal dialog for password errors, use inline messages:

• Inline Error: Place the error message directly below the password field.

• Highlighted Field: Highlight the password field with a red border or background to indicate that there’s an issue.
  

Example:

• Before: Modal dialog with error message: "Invalid password. Your password needs to be at least eight characters including a lowercase letter, an uppercase letter, a number, and a special character."

• After: Inline error message below the password field: "Your password needs to be at least eight characters including a lowercase letter, an uppercase letter, a number, and a special character."
  

Conclusion

Effective error handling on mobile devices enhances the user experience by reducing frustration and cognitive load. Avoid using modal dialogs for displaying errors in forms. Instead, use inline error messages that provide immediate feedback and remain visible until the issue is resolved. This approach aligns with usability best practices, ensuring a smoother and more user-friendly interaction.