Project Reference

This document describes the public APIs, widgets, and the platform channel used by this Flutter application.

Dart APIs (lib/main.dart)

void main()

Entry point that bootstraps the Flutter application.

Example:

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

class MyApp extends StatelessWidget

Root widget that configures application-wide MaterialApp settings.

• title: 'Android GUID'
• theme: Seeded ColorScheme with Material 3
• home: MyHomePage

Usage:

const app = MyApp();
runApp(app);

class MyHomePage extends StatefulWidget

Top-level screen that displays the device GUID fetched via a platform channel.

Constructor:

• MyHomePage({ Key? key, required String title })

Public members:

• final String title — AppBar title.

Usage:

MaterialApp(
  home: const MyHomePage(title: 'Get Android GUID'),
);

Future<String?> _getDeviceGUID()

Asynchronously invokes the platform channel method getDeviceGUID and updates the view state with the returned Android ID. Returns the GUID string or null on failure.

Notes:

• The method catches PlatformException and returns null.
• On success, it updates the _deviceGUID state.

Example (call from UI):

ElevatedButton(
  onPressed: _getDeviceGUID,
  child: const Text('Get Device GUID'),
);

Widgets

The page shows:

• Current GUID text bound to _deviceGUID
• A button to trigger _getDeviceGUID()

Platform Channel API

Channel name:

• com.example.get_android_guid/guid

Method(s):

• getDeviceGUID → String (Android ID)

Android implementation: android/app/src/main/kotlin/com/example/get_android_guid/MainActivity.kt

private val CHANNEL = "com.example.get_android_guid/guid"

override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
    MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL).setMethodCallHandler { call, result ->
        if (call.method == "getDeviceGUID") {
            val guid = Settings.Secure.getString(contentResolver, Settings.Secure.ANDROID_ID)
            result.success(guid)
        } else {
            result.notImplemented()
        }
    }
}

Dart client usage:

static const platform = MethodChannel('com.example.get_android_guid/guid');

final String? androidId = await platform.invokeMethod<String>('getDeviceGUID');

Behavior and return values

• On Android: Returns the device-specific Settings.Secure.ANDROID_ID as a String.
• On other platforms: The method is not implemented natively; the Dart side will throw MissingPluginException if invoked. The current code only calls it on button press and catches PlatformException.

Error handling

• PlatformException on Dart side is caught and results in a null return.
• notImplemented is returned from Android when an unknown method is called on the channel.

Extending the API

To add more methods, use the same channel and switch on call.method in Android (and analogous on iOS if implemented), then expose typed wrappers in Dart.