Radio buttons in Flutter - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a radio button in Flutter?

A radio button lets the user select one option from a set of choices. Only one radio button in the group can be selected at a time.

beginner

How do you group radio buttons in Flutter?

You group radio buttons by giving them the same groupValue. This tells Flutter which buttons belong together and which one is selected.

beginner

What property do you use to handle the selected radio button change?

Use the onChanged callback property. It runs when the user taps a radio button, letting you update the selected value.

beginner

Why should radio buttons be used instead of checkboxes for some choices?

Radio buttons are for choosing only one option from many. Checkboxes allow multiple selections. Use radio buttons when only one answer is allowed.

intermediate

How can you make radio buttons accessible in Flutter?

Use semantic labels with Semantics widget or MaterialTapTargetSize to ensure screen readers can describe the radio buttons clearly.

What does the groupValue property do in Flutter radio buttons?

A Sets the color of the radio button

B Changes the size of the radio button

C Handles the tap event on the radio button

D Defines which radio button is selected in the group

The groupValue tells Flutter which radio button is currently selected among a group of radio buttons.

Which callback is used to detect when a radio button is selected?

A onChanged

B onTap

C onSelect

D onPressed

The onChanged callback runs when the user selects a radio button, allowing you to update the selected value.

If you want users to select multiple options, which widget should you use instead of radio buttons?

A Slider

B Switch

C Checkbox

D Dropdown

Checkboxes allow multiple selections, unlike radio buttons which allow only one.

What happens if two radio buttons have different groupValue values?

A They belong to different groups and can be selected independently

B They will both be selected at the same time

C Flutter throws an error

D They become disabled

Different groupValue means different groups, so each group manages its own selection.

How can you improve accessibility for radio buttons in Flutter?

A Use only colors to show selection

B Add semantic labels describing each option

C Disable the radio buttons

D Remove labels to reduce clutter

Semantic labels help screen readers describe the radio buttons to users with disabilities.

Explain how to create a group of radio buttons in Flutter and handle user selection.

Think about how Flutter knows which button is selected and how you update that.

Describe why radio buttons are preferred over checkboxes when only one choice is allowed.

Consider how users expect to interact with these controls.