Why input widgets capture user data in Flutter - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a text input field that captures user input.

Flutter

TextField(controller: [1])

Drag options to blanks, or click blank then click option'

AinputText

BmyController

CTextEditingController()

DTextField()

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name instead of creating a TextEditingController instance.

Passing the TextField widget itself as controller.

The controller property needs a TextEditingController instance to capture and manage the input text.

2fill in blank

medium

Complete the code to read the current text from the input controller.

Flutter

String userInput = [1].text;

Drag options to blanks, or click blank then click option'

ATextEditingController

BTextField

CmyController

DinputValue

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to get text from the TextField widget instead of the controller.

Using the class name instead of the controller instance.

The text property of the TextEditingController instance holds the current input string.

3fill in blank

hard

Fix the error in the code to update the UI when the user types in the input field.

Flutter

myController.[1](() {
  setState(() {});
});

Drag options to blanks, or click blank then click option'

AaddListener

BonChanged

Ctext

Ddispose

Attempts:

3 left

💡 Hint

Common Mistakes

Using onChanged on the controller instead of the TextField widget.

Trying to access text as a method.

The addListener method registers a callback to run when the text changes, allowing UI updates.

4fill in blank

hard

Fill both blanks to create a TextField that updates a variable when the user types.

Flutter

TextField(onChanged: ([1]) {
  [2] = [1];
})

Drag options to blanks, or click blank then click option'

Avalue

BinputText

Ctext

Dcontroller

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong parameter names in the callback.

Assigning the variable to the parameter instead of the other way.

The onChanged callback provides the new input as value, which we assign to inputText to store the user data.

5fill in blank

hard

Fill all three blanks to create a controller, assign it to a TextField, and dispose it properly.

Flutter

final [1] = TextEditingController();

@override
void dispose() {
  [1].[2]();
  super.dispose();
}

Widget build(BuildContext context) {
  return TextField(controller: [3]);
}

Drag options to blanks, or click blank then click option'

AmyController

Bdispose

Dclear

Attempts:

3 left

💡 Hint

Common Mistakes

Not disposing the controller causing memory leaks.

Using different variable names inconsistently.

You create a controller named myController, dispose it in the dispose() method to free resources, and assign it to the TextField.