javascript - 如何在事件处理函数内部调用函数 react native

Question

我实现了这个库https://github.com/elanic-tech/react-native-paytm在我的项目中。我成功收到 Paytm 的回复onPayTmResponse 但现在我想将此响应发送到服务器，但在这个函数内，我无法调用任何函数或声明它给我一个未定义的错误。

componentWillMount() {
        if(Platform.OS == 'ios'){
            const { RNPayTm } = NativeModules
            const emitter = new NativeEventEmitter(RNPayTm)
            emitter.addListener('PayTMResponse', this.onPayTmResponse)
        }else{
            DeviceEventEmitter.addListener('PayTMResponse', this.onPayTmResponse)
        }

        //this.makeRemoteRequest();
}

onPayTmResponse(response) {
        // Process Response
        // response.response in case of iOS
        // reponse in case of Android

        var actual = "";
        if(Platform.OS == 'ios'){
            actual = JSON.parse(response.response);
        }else{
            actual = JSON.parse(response);
        }

        console.log(actual, this.state);

        if(actual.RESPCODE == "01"){
            // Place Order
            placeOrder();
        }else{
            alert(actual.RESPMSG);
            this.setState({loading: false, buttonText: 'Continue'});
        }
    }

Error

Answer 1

将您的 onPayTmResponse 函数与 componentWillMount 内的此函数绑定(bind)，例如

componentWillMount() {
  this.onPayTmResponse = this.onPayTmResponse.bind(this); // note: we bind onPayTmResponse with this
  if(Platform.OS == 'ios'){
    const { RNPayTm } = NativeModules
    const emitter = new NativeEventEmitter(RNPayTm)
    emitter.addListener('PayTMResponse', this.onPayTmResponse)
  }else{
    DeviceEventEmitter.addListener('PayTMResponse', this.onPayTmResponse)
  }
  //this.makeRemoteRequest();
}

现在您应该能够在 onPayTmResponse 中调用 setState。