callbackDispatcher function

void callbackDispatcher()

Implementation

void callbackDispatcher() {
  // 1. Initialize MethodChannel used to communicate with the platform portion of the plugin.
  const MethodChannel _backgroundChannel = MethodChannel('android_location_background');

  // 2. Setup internal state needed for MethodChannels.
  WidgetsFlutterBinding.ensureInitialized();

  // 3. Listen for background events from the platform portion of the plugin.
  _backgroundChannel.setMethodCallHandler((MethodCall call) async {
    final args = call.arguments;

    print('Received callback invocation with arguments:');
    print('\n');
    print(args);
    // 3.1. Retrieve callback instance for handle.
    final Function callback = PluginUtilities.getCallbackFromHandle(CallbackHandle.fromRawHandle(args[0]));
    //assert(callback != null);

    if (callback == null) {
      print('Callback is null');
    } else {
      print('Callback is not null');

      try {
        // 3.2. Preprocess arguments.
        final coordinates = args[1];
        print(coordinates);
        // 3.3. Invoke callback.
        callback(coordinates);
      } catch(Exception) {
        print(Exception);
      }
    }
  });

  // 4. Alert plugin that the callback handler is ready for events.
  _backgroundChannel.invokeMethod('initialized');
}