Flutter Form Validation Tutorial using TextFormField: Flutter tutorial with Dart #3.8

Understand how to implement validation in your Flutter application in three steps:
1. Use FORM with Global Key
2. Use TextFormField with a validator property
3. Use a Button to validate form fields and display validation errors

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Let's get in touch! [Sriyank Siddhartha]

---- Thank you for your love and support ----

[gadgetologist]

I appreciate your fine work on this and the Dart series. Thank you so much for taking the time to make them. Excellent work!

[garethbeall]

Thank you so much for taking the time to provide your expertise - I am really enjoying this series. It's a great introduction into the Flutter world!

[chaitanyadeshpande]

Just have to add

else if (value != TextInputType.number)
return 'Invalid Input';

this condition after if condition, and you are ready to go.
Thank you Smartherd for these really helpful tutorials.

[karthigadevi]

Thank you new to app development.. ... Finally created simpleinterest calculator app.. More and more blessings to your humble work.. Pls keep going.. Thanks alot...

[karthikgokul]

Hello Sir, awaiting for a next session with database

[rajansingla]

I have learnt a lot from your videos weather it's for android, java or now in flutter. Your teaching level is just incredible. Really enjoyed your all fruitful tutorials. God bless you.

And can you please make a video like this but use phone text form field with using country codes. It would really be appreciable. Thanks a lot !! 😊

[amitkumarsahoo]

For validate the fields :
if (value.isEmpty || double.tryParse(value) == null) {
return 'Please provide Principal amount';
}

[venky]

Third section successfully completed
But clicking on the rupees or dollars it changes, but it appears blur screen on clicking
Thank you so much ❤️

[vivekchavda]

Hey @smartherd thanks for providing this course.
I learned many new things in this course thank you so much.

[MsSplashIt]

I hope you will do a whole course on firebase/firestore (authentication, role based authorization, crud, storing images and retrieving etc.) really enjoying your courses on flutter and dart. thanks for taking the time to make them

[gopi]

i like your videos a lot .. so simple and so precise, hopefully i get access to your plural sight videos for free ;), please do more videos on youtube on flutter

[dhanshrigunjwate]

Thank you so much sir, First time I created flutter application. Your video very nice 👌.

[akashbhujbal]

Waiting for our new season
Kabhi kabhi lagta hai sir aap hi bhagwan hai....😂😘
Verry nice thank u🙏

[swarajdash]

Hello sir, thanks to you and GDG bbsr's workshop I've already learnt so much of Dart and Flutter. I never did any development in Android Studio with Java, xml etc and directly started with Flutter (and feel comfortable). So should I continue with Flutter or should I learn the usual way and do Flutter later?

[ericjonas]

Can't wait for the next episodes? To be honest, it's the 1st series which I complete all of them till now. Really good.

Just a lil feedback, maybe you can minimize the word "perfect".. repeated quite a few times though :P

[abenezerleta]

thank you bro, you make me to enjoy flutter

[refreshing_morning]

Sir, when will you upload another video? Can't wait for database series to be out.

[TheChartwhisperers]

How to add separators in the textfield for better user experience??

[sharmavikas]

sir i could not find how to validate for number only while entering rate of interest
i see that we kept the keyboard to insert number only but i quickly found out that we can copy and paste text to the rate of interest field
and also we can insert negative number (i am working on android emulator ).

[btoeltagmo]

Why in valditor we put in parameters string value
While we in principal text field
We enter numbers