Flutter – CupertinoPicker Widget

The CupertinoPicker widget in Flutter is part of the Cupertino-themed widgets that mimic the design and behavior of iOS widgets. It’s specifically designed to create a scrollable list of items, allowing the user to select one item from the list by scrolling or picking it directly. In this article, we are going to implement the CupertinoPicker widget. A sample video is given below to get an idea about what we are going to do in this article.

Basic Syntax of CupertinoPicker Widget

CupertinoPicker(
  itemExtent: 40.0, // Height of each item in the picker
  onSelectedItemChanged: (int index) {
    // Callback function when an item is selected
    // Use 'index' to determine which item was selected
  },
  children: <Widget>[
    // List of widgets representing each item in the picker
    Center(
      child: Text('Item 1'),
    ),
    Center(
      child: Text('Item 2'),
    ),
    // Add more items as needed
  ],
)

Required Tools

To build this app, you need the following items installed on your machine:

• Visual Studio Code / Android Studio
• Android Emulator / iOS Simulator / Physical Device device.
• Flutter Installed
• Flutter plugin for VS Code / Android Studio.

Step By Step Implementation

Step 1: Create a New Project in Android Studio

To set up Flutter Development on Android Studio please refer to Android Studio Setup for Flutter Development, and then create a new project in Android Studio please refer to Creating a Simple Application in Flutter.

Step 2: Import the Package

First of all import material.dart file.

import 'package:flutter/cupertino.dart';

Step 3: Execute the main Method

Here the execution of our app starts.

Dart

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

Step 4: Create MyApp Class

In this class we are going to implement the CupertinoApp , here we can also set the Theme of our App.Here we call MyPickerPage class where the CupertinoPicker Widget is implemented .

Dart

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return CupertinoApp(
      debugShowCheckedModeBanner: false,
      home: MyPickerPage(),
    );
  }
}

Step 5: Create MyPickerPage Class

In this class we are going to Implement the CupertinoPicker widget that help to create a scrollable list of items, allowing the user to select one item from the list by scrolling or picking it directly and the selected item is displayed using a TextView. Comments are added for better understanding.

 CupertinoPicker(
              itemExtent: 40.0,
              onSelectedItemChanged: (int index) {
                // Update the selected item index when an item is changed
                setState(() {
                  selectedItemIndex = index;
                });
              },
              children: List<Widget>.generate(items.length, (int index) {
                // Generate the picker items based on the 'items' list
                return Center(
                  child: Text(
                    items[index],
                    style: TextStyle(fontSize: 24.0),
                  ),
                );
              }),
            ),

Dart

class MyPickerPage extends StatefulWidget {
  @override
  _MyPickerPageState createState() => _MyPickerPageState();
}

class _MyPickerPageState extends State<MyPickerPage> {
  // List of items for the picker
  List<String> items = ['Item 1', 'Item 2', 'Item 3', 'Item 4', 'Item 5'];

  // Selected item index
  int selectedItemIndex = 0;

  @override
  Widget build(BuildContext context) {
    return CupertinoPageScaffold(
      // App bar with title
      navigationBar: CupertinoNavigationBar(
        middle: Text('Cupertino Picker Example'),
      ),
      // Main content
      child: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            // Display "Selected Item:" text
            Text(
              'Selected Item:',
              style: TextStyle(fontSize: 20.0),
            ),
            SizedBox(height: 20.0), // Spacer

            // CupertinoPicker widget for item selection
            CupertinoPicker(
              itemExtent: 40.0,
              onSelectedItemChanged: (int index) {
                // Update the selected item index when an item is changed
                setState(() {
                  selectedItemIndex = index;
                });
              },
              children: List<Widget>.generate(items.length, (int index) {
                // Generate the picker items based on the 'items' list
                return Center(
                  child: Text(
                    items[index],
                    style: TextStyle(fontSize: 24.0),
                  ),
                );
              }),
            ),
            SizedBox(height: 20.0), // Spacer

            // Display the selected item
            Text(
              'Selected: ${items[selectedItemIndex]}',
              style: TextStyle(fontSize: 20.0),
            ),
          ],
        ),
      ),
    );
  }
}

Here is the full Code of main.dart file

Dart

import 'package:flutter/cupertino.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return CupertinoApp(
      debugShowCheckedModeBanner: false,
      home: MyPickerPage(),
    );
  }
}

class MyPickerPage extends StatefulWidget {
  @override
  _MyPickerPageState createState() => _MyPickerPageState();
}

class _MyPickerPageState extends State<MyPickerPage> {
  // List of items for the picker
  List<String> items = ['Item 1', 'Item 2', 'Item 3', 'Item 4', 'Item 5'];

  // Selected item index
  int selectedItemIndex = 0;

  @override
  Widget build(BuildContext context) {
    return CupertinoPageScaffold(
      // App bar with title
      navigationBar: CupertinoNavigationBar(
        middle: Text('Cupertino Picker Example'),
      ),
      // Main content
      child: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            // Display "Selected Item:" text
            Text(
              'Selected Item:',
              style: TextStyle(fontSize: 20.0),
            ),
            SizedBox(height: 20.0), // Spacer

            // CupertinoPicker widget for item selection
            CupertinoPicker(
              itemExtent: 40.0,
              onSelectedItemChanged: (int index) {
                // Update the selected item index when an item is changed
                setState(() {
                  selectedItemIndex = index;
                });
              },
              children: List<Widget>.generate(items.length, (int index) {
                // Generate the picker items based on the 'items' list
                return Center(
                  child: Text(
                    items[index],
                    style: TextStyle(fontSize: 24.0),
                  ),
                );
              }),
            ),
            SizedBox(height: 20.0), // Spacer

            // Display the selected item
            Text(
              'Selected: ${items[selectedItemIndex]}',
              style: TextStyle(fontSize: 20.0),
            ),
          ],
        ),
      ),
    );
  }
}

Output: