bind library to dart and demo in app

README.md

@@ -8,12 +8,17 @@ sudo apt install libboost-thread-dev
 ```
 
 ## Build
-Build:
+Build the native library for your platform like:
 ```sh
 cd flutter_libsparkmobile/scripts/linux
 ./build_all.sh
 ```
 
+## Example
+See the [example](example) directory for a Flutter app that uses `flutter_libsparkmobile`.
+
+You must have the native library built for your platform before running the example app.  See the [Build](#build) section above.
+
 ## Development
 ### Bindings generation (`dart ffigen`)
 Bindings are generated using [ffigen](https://pub.dev/packages/ffigen).  All of the individual build scripts in your platform's `build_all.sh` script must be run up to and including `copyCMakeLists.sh` in order for the header referenced in `pubspec.yaml`'s `ffigen` section to exist.

example/lib/main.dart

@@ -1,6 +1,8 @@
-import 'package:flutter/material.dart';
 import 'dart:async';
+import 'dart:ffi';
+import 'dart:io';
 
+import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_libsparkmobile/flutter_libsparkmobile.dart';
 
@@ -17,7 +19,26 @@ class MyApp extends StatefulWidget {
 
 class _MyAppState extends State<MyApp> {
   String _platformVersion = 'Unknown';
-  final _flutterLibsparkmobilePlugin = FlutterLibsparkmobile();
+  final FlutterLibsparkmobile _flutterLibsparkmobilePlugin;
+
+  _MyAppState()
+      : _flutterLibsparkmobilePlugin = FlutterLibsparkmobile(_loadLibrary());
+
+  static DynamicLibrary _loadLibrary() {
+    if (Platform.isLinux) {
+      return DynamicLibrary.open('libsparkmobile.so');
+    } else if (Platform.isAndroid) {
+      // return DynamicLibrary.open('libsparkmobile.so');
+    } else if (Platform.isIOS) {
+      // return DynamicLibrary.open('libsparkmobile.dylib');
+    } else if (Platform.isMacOS) {
+      // return DynamicLibrary.open('libsparkmobile.dylib');
+    } else if (Platform.isWindows) {
+      // return DynamicLibrary.open('sparkmobile.dll');
+    }
+    // Optionally throw an error or handle other platforms
+    throw UnsupportedError('This platform is not supported');
+  }
 
   @override
   void initState() {
@@ -32,7 +53,8 @@ class _MyAppState extends State<MyApp> {
     // We also handle the message potentially returning null.
     try {
       platformVersion =
-          await _flutterLibsparkmobilePlugin.getPlatformVersion() ?? 'Unknown platform version';
+          await _flutterLibsparkmobilePlugin.getPlatformVersion() ??
+              'Unknown platform version';
     } on PlatformException {
       platformVersion = 'Failed to get platform version.';
     }
@@ -55,7 +77,23 @@ class _MyAppState extends State<MyApp> {
           title: const Text('Plugin example app'),
         ),
         body: Center(
-          child: Text('Running on: $_platformVersion\n'),
+          child: Column(
+            children: [
+              Text('Running on: $_platformVersion\n'),
+              // A button that, when pressed, generates a new Spark spend key.
+              ElevatedButton(
+                onPressed: () async {
+                  final spendKey = await _flutterLibsparkmobilePlugin
+                      .generateSpendKey()
+                      .catchError((error) {
+                    print(error);
+                  });
+                  print(spendKey);
+                },
+                child: const Text('Generate spend key'),
+              ),
+            ],
+          ),
         ),
       ),
     );

example/linux/CMakeLists.txt

@@ -119,6 +119,10 @@ install(FILES "${FLUTTER_ICU_DATA_FILE}" DESTINATION "${INSTALL_BUNDLE_DATA_DIR}
 install(FILES "${FLUTTER_LIBRARY}" DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
   COMPONENT Runtime)
 
+install(FILES "${CMAKE_CURRENT_SOURCE_DIR}/../../scripts/linux/build/libsparkmobile.so" DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
+  COMPONENT Runtime)
+# Must have ran build script(s) in order for this library to exist.
+
 foreach(bundled_library ${PLUGIN_BUNDLED_LIBRARIES})
   install(FILES "${bundled_library}"
     DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"

lib/flutter_libsparkmobile.dart

@@ -1,8 +1,27 @@
+import 'dart:ffi';
 
+import 'package:ffi/ffi.dart';
+
+import 'flutter_libsparkmobile_bindings.dart';
 import 'flutter_libsparkmobile_platform_interface.dart';
 
 class FlutterLibsparkmobile {
+  final SparkMobileBindings _bindings;
+
+  FlutterLibsparkmobile(DynamicLibrary dynamicLibrary)
+      : _bindings = SparkMobileBindings(dynamicLibrary);
+
   Future<String?> getPlatformVersion() {
     return FlutterLibsparkmobilePlatform.instance.getPlatformVersion();
   }
+
+  // SparkMobileBindings methods
+  Future<String> generateSpendKey() {
+    Pointer<Char> key = _bindings.generateSpendKey();
+
+    // Cast the Pointer<Char> to a Dart String.
+    final keyString = key.cast<Utf8>().toDartString();
+
+    return Future.value(keyString);
+  }
 }

lib/flutter_libsparkmobile_bindings.dart

@@ -0,0 +1,34 @@
+// ignore_for_file: camel_case_types, non_constant_identifier_names, unused_element, unused_field, return_of_invalid_type, void_checks, annotate_overrides, no_leading_underscores_for_local_identifiers, library_private_types_in_public_api
+
+// AUTO GENERATED FILE, DO NOT EDIT.
+//
+// Generated by `package:ffigen`.
+// ignore_for_file: type=lint
+import 'dart:ffi' as ffi;
+
+/// Bindings for sparkmobile.
+class SparkMobileBindings {
+  /// Holds the symbol lookup function.
+  final ffi.Pointer<T> Function<T extends ffi.NativeType>(String symbolName)
+      _lookup;
+
+  /// The symbols are looked up in [dynamicLibrary].
+  SparkMobileBindings(ffi.DynamicLibrary dynamicLibrary)
+      : _lookup = dynamicLibrary.lookup;
+
+  /// The symbols are looked up with [lookup].
+  SparkMobileBindings.fromLookup(
+      ffi.Pointer<T> Function<T extends ffi.NativeType>(String symbolName)
+          lookup)
+      : _lookup = lookup;
+
+  ffi.Pointer<ffi.Char> generateSpendKey() {
+    return _generateSpendKey();
+  }
+
+  late final _generateSpendKeyPtr =
+      _lookup<ffi.NativeFunction<ffi.Pointer<ffi.Char> Function()>>(
+          'generateSpendKey');
+  late final _generateSpendKey =
+      _generateSpendKeyPtr.asFunction<ffi.Pointer<ffi.Char> Function()>();
+}

pubspec.yaml

@@ -8,10 +8,12 @@ environment:
   flutter: ">=3.3.0"
 
 dependencies:
+  ffi: ^2.1.0
   flutter:
     sdk: flutter
   plugin_platform_interface: ^2.0.2
   test: ^1.24.1
+  typed_data: ^1.3.2
 
 dev_dependencies:
   flutter_test:
@@ -80,10 +82,10 @@ flutter:
   # https://flutter.dev/custom-fonts/#from-packages
 
 ffigen:
-  name: flutter_libsparkmobile
+  name: SparkMobileBindings
   description: Bindings for sparkmobile.
   language: c
-  output: 'lib/sparkmobile_bindings.dart'
+  output: 'lib/flutter_libsparkmobile_bindings.dart'
   headers:
     entry-points:
       - 'scripts/linux/sparkmobile/src/dart_interface.h'