Use React's useEffect to optimize your application's performance.Learn how LogRocket's Galileo cuts through the noise to proactively resolve issues in your app.Don't miss a moment with The Replay, a curated newsletter from LogRocket.For one or two text fields, it’s not so bad, but it’s easy to see how it could scale poorly. Second, you have to write your own validation logic for simple things such as checking if a number is correct.įinally, this approach results in quite a lot of boilerplate code.
It’s easy to see how you could wind up with quite a few of these, which you would have to keep track of yourself. Let’s break down why that’s the case.įirst, if you want to be able to get the text from a field or clear the field’s input, you have to create your own TextEditingController for each field. Using forms in Flutter isn’t unduly difficult, but hand-crafting our own forms can get a bit laborious. Issues with manually creating forms in Flutter When the user selects a type of pet, we also want to iterate through the previous answers given to these questions and clear them so that only one option is selected at a time.įor (final controller in questionResponses) '), This is a RadioListTile that lets the user select what kind of pet they are bringing in: Cat, Dog, or Echidna. Return 'Only enter numbers in the phone number field' The phone number input field is a little bit different, as we need to both validate that it has a valid phone number in it as well as prompt the user when invalid input is detected: TextFormField(ĭecoration: InputDecoration(hintText: 'Phone number'),ĪutovalidateMode: AutovalidateMode.always, To write text into these fields, we’ll create the TextFormField widgets and bind them to the appropriate controllers: TextFormField(ĭecoration: InputDecoration(hintText: 'First Name'),ĭecoration: InputDecoration(hintText: 'Last Name'), Let’s create those variables now: final _formKey = GlobalKey() įinal firstName = TextEditingController() įinal lastName = TextEditingController() įinal questionResponses = List.generate(3, (index) => TextEditingController()) We’re also responsible for creating a variable that will house the selected pet. In this first approach, we’re manually creating the forms ourselves, and we would also like to capture the text inputs that are in these individual fields.īecause of this, we’re responsible for creating individual TextControllers that we can associate to the TextFormField widgets. Making the form in Flutter without reactive forms
Next, the answers to those three questions are required, so we must add Flutter form validation logic to ensure they are filled out.įinally, the phone number must only contain numbers, so if it contains non-numeric values, then the form should reject that entry and inform the user. The end result will look like this:įirst, the three followup questions must change depending on what type of pet the user selects. In order for this app to work, people need to give details such as their name and phone number, what kind of pet they have, and their pet’s likes and dislikes. The app we will create is an enrollment app for pets into a “pet hotel” - a place where people can drop their pets off when they go on vacation.
Flutter form validation example popup message box registration#
In this article, we’ll create a registration form with input validation and fields that change based on the value of other fields. Normally, these input fields, whether they are text fields, date fields, or any other type of input, are referred to as “controls.” Validation can also become an issue, as even simple validation for certain fields can require lengthy custom validators to be written. However, as more fields and input types are added to a form, capturing this information rapidly increases in complexity. Fortunately, capturing text inputs is fairly simple within Flutter. In almost every app that you develop, sooner or later there will arise a need to capture user input. Given the chance, I'll talk to you for far too long about why I love Flutter so much. Lewis Cianci Follow I'm a passionate mobile-first developer, and I've been making apps with Flutter since it first released.
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