Update the UI based on orientation

In some situations, you want to update the display of an app when the user rotates the screen from portrait mode to landscape mode. For example, the app might show one item after the next in portrait mode, yet put those same items side-by-side in landscape mode.

In Flutter, you can build different layouts depending on a given Orientation. In this example, build a list that displays two columns in portrait mode and three columns in landscape mode using the following steps:

1. Build a GridView with two columns.
2. Use an OrientationBuilder to change the number of columns.

First, create a list of items to work with. Rather than using a normal list, create a list that displays items in a grid. For now, create a grid with two columns.

return GridView.count(
  // A list with 2 columns
  crossAxisCount: 2,
  // ...
);

To learn more about working with GridViews, see the Creating a grid list recipe.

To determine the app's current Orientation, use the OrientationBuilder widget. The OrientationBuilder calculates the current Orientation by comparing the width and height available to the parent widget, and rebuilds when the size of the parent changes.

Using the Orientation, build a list that displays two columns in portrait mode, or three columns in landscape mode.

body: OrientationBuilder(
  builder: (context, orientation) {
    return GridView.count(
      // Create a grid with 2 columns in portrait mode,
      // or 3 columns in landscape mode.
      crossAxisCount: orientation == Orientation.portrait ? 2 : 3,
    );
  },
),

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    const appTitle = 'Orientation Demo';

    return const MaterialApp(
      title: appTitle,
      home: OrientationList(
        title: appTitle,
      ),
    );
  }
}

class OrientationList extends StatelessWidget {
  final String title;

  const OrientationList({super.key, required this.title});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(title)),
      body: OrientationBuilder(
        builder: (context, orientation) {
          return GridView.count(
            // Create a grid with 2 columns in portrait mode, or 3 columns in
            // landscape mode.
            crossAxisCount: orientation == Orientation.portrait ? 2 : 3,
            // Generate 100 widgets that display their index in the List.
            children: List.generate(100, (index) {
              return Center(
                child: Text(
                  'Item $index',
                  style: Theme.of(context).textTheme.displayLarge,
                ),
              );
            }),
          );
        },
      ),
    );
  }
}

In the previous section, you learned how to adapt the app UI to device orientation changes.

Flutter also allows you to specify the orientations your app supports using the values of DeviceOrientation. You can either:

• Lock the app to a single orientation, like only the portraitUp position, or...
• Allow multiple orientations, like both portraitUp and portraitDown, but not landscape.

In the application main() method, call SystemChrome.setPreferredOrientations() with the list of preferred orientations that your app supports.

To lock the device to a single orientation, you can pass a list with a single item.

For a list of all the possible values, check out DeviceOrientation.

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  SystemChrome.setPreferredOrientations([
    DeviceOrientation.portraitUp,
  ]);
  runApp(const MyApp());
}