What is LayoutBuilder in Flutter?
Why Interviewers Ask This
This question targets practical, hands-on experience with Flutter. Interviewers want to see if you've worked with these concepts in real projects, not just read about them. Strong answers include concrete examples.
Answer
LayoutBuilder provides access to the parent widget's constraints inside the build method, enabling truly responsive layouts. Its builder function receives a BoxConstraints object with maxWidth and maxHeight, letting you make layout decisions based on the available space. For example, show a two-column layout when maxWidth > 600, otherwise single-column. This is more reliable than using MediaQuery for nested layouts because it reflects the actual available space, not the full screen size.
Pro Tip
This topic has Flutter-specific nuances that differ from general programming. Highlighting those nuances in your answer shows expertise rather than generic knowledge.