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Flutter: Input Validation with RegExp

This video is about Input Validation and RegExp.

As part of this, I'll give you an overview of regular expressions (regex) and how they work by using a live web regex validator.

Then we will see how to implement a Regex validator in Dart and integrate it with Flutter's TextField widget, so that we can validate user input.

I will use a demo app to illustrate two sample use cases: - Make a payment (numeric validator with 2 decimal digits, 4 non-decimal digits) - Forgot password (email input validation)


  • Demo app preview
  • Regex web examples
  • Regex in Flutter
  • Input Validation Page & TextField
  • TextInputFormatter
  • Email validation
  • Editing / submitting text
  • InputValidationPage implementation
  • keeping focus on the keyboard
  • Wrap up


  • I'm using the iOS simulator, but you can open the Android emulator and run the same code.
  • This code was tested with Flutter Beta 0.8.2.

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