在Flutter插件中不会触发PaymentAuthorizationViewController

Question

我正在通过Flutter插件中的方法通道通过本地Braintree SDK集成Apple Pay。

当我将代码放入FlutterPlugin类中时，集成成功。

但是，当我尝试将代码放在单独的swift类中时，它不起作用。

我想念什么？

在此代码中，可以在按下ApplePay付款表中的付款按钮后触发PaymentAuthorizationViewController。

hadoop jar /usr/hadoop-3.0.0/share/hadoop/tools/lib/hadoop-streaming-3.0.0.jar \
-file ./checkinsmapper.py \
-mapper ./checkinsmapper.py \
-file ./checkinsreducer.py \
-reducer ./checkinsreducer.py \
-input /yelp_checkin.csv \
-output /output

如果我将代码放在其他类中，则不会触发paymentAuthorizationViewController。

public class SwiftBraintreePlugin:NSObject,
        PKPaymentAuthorizationViewControllerDelegate,FlutterPlugin{

    public static func register(with registrar:FlutterPluginRegistrar){
        let channel=FlutterMethodChannel(name:"braintree",
                binaryMessenger:registrar.messenger())

        let instance=SwiftBraintreePlugin()

        registrar.addMethodCallDelegate(instance,channel:channel)
    }

    public func handle(_ call:FlutterMethodCall, result:@escaping FlutterResult){
    }

    public func paymentAuthorizationViewController(_ controller:PKPaymentAuthorizationViewController,
        didAuthorizePayment payment:PKPayment,completion:@escaping(PKPaymentAuthorizationStatus) ->Void) {
    }

    @available(iOS8.0, *)
    public func paymentAuthorizationViewControllerDidFinish(_ controller:PKPaymentAuthorizationViewController){
        viewController.dismiss(animated:true,completion:nil)
    }

}