Question

我正在努力将Particle Device Setup Library集成到Flutter应用程序中。我已遵循Flutter.io的示例，说明如何集成Platform Channels以将Flutter应用程序与本机代码桥接。我已经成功打开了与本机Particle SDK的连接，并且可以配置Photon。但是，我不能从这里前进。

我的目的是在从设置阶段成功返回时将用户重定向到新页面。如果设置阶段失败，则用户应该可以重新开始（此功能尚未实现）。

在ParticleSetupState内的initState()类中，我叫initiateParticleSetup();。

我已经初始化了以下变量：

static const platform = const MethodChannel("unique_placeholder/particle-setup");
String _particleSetup = "awaiting";
String particleSetup = "placeholder";

initParticleSetup()的结构如下：

Future<Null> initiateParticleSetup() async {  
            String route = "";
            Map<String, dynamic> arguments = {};
            arguments.putIfAbsent("route", () => route);
            print("route: $route");
            try {
              tempRoute = await platform.invokeMethod("initParticleSetup", arguments);
              // Must be a valid route or a parameter passed back from the result of
              // the setup phase making the application navigate to the next screen 
              // upon successful configuration.
              particleSetup = route;
            } catch (e) {
              particleSetup = "Error: $e"; // Should allow the users to configure the setup again.
            }

            if(!mounted) { return; }
            print("After finishing native code: $route"); // This line is causing the the VERBOSE-2 errors messages
          }

AppDelegate包含以下代码：

   override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?
        ) -> Bool {

        let controller : FlutterViewController = window?.rootViewController as! FlutterViewController;
        let initParticleSetupChannel = FlutterMethodChannel.init(name: "unique_placeholder/particle-setup", binaryMessenger: controller);

        initParticleSetupChannel.setMethodCallHandler({
            (call: FlutterMethodCall, result: FlutterResult) -> Void in                
            if ("initParticleSetup" == call.method) {
                print("Just entered initParticleSetup")
                let argument = call.arguments as? NSDictionary
                var route = argument!["route"] as? String
                print("initial route: \(route)")
                self.initParticleSetup(result: result)
                route = "/proceed"
                print("route is overwritten: \(route)")
                result(route)

                print("leaving initParticleSetup")
            } else {
                result(FlutterMethodNotImplemented);
            }
        });

        GeneratedPluginRegistrant.register(with: self)
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }

    private func initParticleSetup(result: FlutterResult) {
        if let setupController = ParticleSetupMainController(setupOnly: true) {
            print("before self.window? stuff")
            self.window?.rootViewController?.present(setupController, animated: true, completion: nil)
            print("after self.window? stuff")
        }
    }

当我完成设置阶段并返回Flutter代码时，控制台中将显示以下错误：

[VERBOSE-2:engine.cc(157)] Could not prepare to run the isolate 
[VERBOSE-2:engine.cc(116)] Engine not prepare and launch isolate.
[VERBOSE-2:FlutterViewController.mm(462)] Could not launch engine with configuration.

我怀疑它是由try {} catch {}方法之后的print（）引起的，因为“在完成本机代码之后：$ route”从未打印到控制台。我不知道如何克服这个问题。

卡在FlutterViewController.mm（462）中无法启动配置引擎

0 个答案: