BuildContext

Learn that BuildContext marks a widget's place in the tree.

BuildContext

BuildContext represents a widget's position in the widget tree. It is passed to the build method and identifies where the widget is and who its parents are. You use context to reach ancestral (ancestor) data such as Theme and MediaQuery.

@override
Widget build(BuildContext context) {
  final theme = Theme.of(context);
  return Text('Hello', style: theme.textTheme.bodyLarge);
}

Accessing ancestors

A widget uses BuildContext to obtain data from its ancestor widgets. Theme.of(context) walks up the tree to find the nearest MaterialApp and returns its theme. Similarly MediaQuery.of(context) gives the screen size.

Widget build(BuildContext context) {
  double width = MediaQuery.of(context).size.width;
  return SizedBox(width: width, child: Text('Full'));
}

Exercise Print context uses

In main, print three lines with print: context konum, Theme tema and MediaQuery boyut.

Show example solution

void main() {
  print('context konum');
  print('Theme tema');
  print('MediaQuery boyut');
}

Test yourself

What does BuildContext represent?
- Widget's color
- Widget's size
- Widget's name
- Widget's position in the tree
Show answer

Widget's position in the tree — BuildContext represents the widget's position in the widget tree and provides access to ancestral data.

Reach theme via context

final tema = ____.of(context);

Show answer

final tema = Theme.of(context);

BuildContext concepts

BuildContext

Widget's position in the tree
context

Parameter of the build method
ancestor

Widget above in the tree
Theme.of(context)

Access to ancestral theme

Next lesson: Material and Cupertino

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