我正在开发 Flutter App 中的原生 Android 小部件。其中有刷新按钮,单击该按钮我必须调用 Flutter 代码中的方法。我正在使用 Flutter Method Channel 进行通信,当应用程序处于前台时它工作正常。但是当应用程序最小化或关闭时它不起作用。我收到错误PlatformException(NO_ACTIVITY, null, null)。下面是我的代码。
安卓 (AppWidgetProvider)
if (methodChannel == null && context != null) {
FlutterMain.startInitialization(context)
FlutterMain.ensureInitializationComplete(context, arrayOf())
// Instantiate a FlutterEngine.
val engine = FlutterEngine(context.applicationContext)
// Define a DartEntrypoint
val entrypoint: DartEntrypoint = DartEntrypoint.createDefault()
// Execute the DartEntrypoint within the FlutterEngine.
engine.dartExecutor.executeDartEntrypoint(entrypoint)
// Register Plugins when in background. When there
// is already an engine running, this will be ignored (although there will be some
// warnings in the log).
//GeneratedPluginRegistrant.registerWith(engine)
methodChannel = MethodChannel(engine.dartExecutor.binaryMessenger, MainActivity.CHANNEL)
}
methodChannel!!.invokeMethod("fetchNewData", "", object : MethodChannel.Result {
override fun notImplemented() {
Toast.makeText(context, "method not implemented", Toast.LENGTH_SHORT).show()
}
override fun error(errorCode: String?, errorMessage: String?, errorDetails: Any?) {
Toast.makeText(context, errorMessage, Toast.LENGTH_SHORT).show()
}
override fun success(result: Any?) {
Toast.makeText(context, "success", Toast.LENGTH_SHORT).show()
}
})
扑
/// calling in main
static Future<void> attachListeners() async {
WidgetsFlutterBinding.ensureInitialized();
var bloc = new AqiCnDashboardBloc();
_channel.setMethodCallHandler((call) {
switch (call.method) {
case 'fetchNewData':
bloc.getAqiCn(false);
return null;
default:
throw MissingPluginException('notImplemented');
}
});
}