为什么我无法在本地运行我的 RN 应用以与本地 api 服务器通信？

Question

我有一个React Native前端和一个Rails API后端，但我似乎无法成功登录。

当我重新加载RN模拟器时，我确实收到以下消息：

RCTBridge 需要dispatch_sync来加载 RCTDevLoadView。这可能会 导致死锁

老实说，我不知道这是否相关。

我知道相关的错误是当我得到：

服务器： 类型错误： 网络请求失败

我可以采取哪些步骤来解决此问题？

我确实可以访问前端和后端代码库。

我想知道问题是否出在这个app/containers/LoginScreen/index.js

：

import React from 'react';
import { ActivityIndicator, StatusBar, Text, View, Linking, Image, TouchableWithoutFeedback, TouchableOpacity, Platform, Keyboard } from 'react-native';
import Analytics from 'react-native-analytics-segment-io';
import KeyboardSpacer from 'react-native-keyboard-spacer';
import PropTypes from 'prop-types';
import { connect } from 'react-redux';
import _ from 'lodash';
import { Images, Colors } from '../../themes';
import { loginUser, getMeQuestions, getMeAnswers, pullOnLoadData, setLoggingIn } from '../../reducers/userReducer';
import { getModuleInfo, getLessonInfo } from '../../reducers/lessonModuleReducer';
import { FrigateButton, FrigateTextInput, HeaderBackButton, NavRightIcon } from '../../components';
import styles from './styles';
class LoginScreen extends React.Component {
  static getDerivedStateFromProps(nextProps, prevState) {
    if (!nextProps.id) {
      return {};
    }
    if (nextProps.id && nextProps.lessons.length > 0 && nextProps.modules.length > 0) {
      if (!prevState.loadedData) {
        nextProps.pullOnLoadData(nextProps.id);
        if (!nextProps.signedCurrentTerms) {
          Analytics.identify('user_id', { id: nextProps.id, email: nextProps.email });
          nextProps.navigation.navigate('TOSPP');
        } else {
          Analytics.identify('user_id', { id: nextProps.id, email: nextProps.email });
          nextProps.navigation.navigate('TabNavigator');
        }
        return { ...prevState, loadedData: true };
      }
    }
    return {};
  }
  constructor(props) {
    super(props);
    this.state = {
      username: '',
      password: '',
      loadedData: false,
    };
    this.loginPressed = this.loginPressed.bind(this);
  }
  loginPressed() {
    Analytics.track('Login Pressed', { email: this.state.username });
    this.props.setLoggingIn(true);
    Keyboard.dismiss();
    this.props.login(
      this.state.username,
      this.state.password,
    );
  }
  render() {
    return (
      <View
        testID="signupScreen"
        style={styles.mainContainer}
      >
        <StatusBar barStyle="light-content" />
        <Image source={Images.background} style={styles.backgroundImage} />
        <View style={styles.brand}>
          <Image source={Images.logo} style={styles.logoImage} />
        </View>
        {!this.props.token &&
          <View style={styles.textInputs}>
            <FrigateTextInput
              onChangeText={text => this.setState({ username: text })}
              label="EMAIL"
              placeholder="EMAIL"
              value={this.state.username}
              keyboardType="email-address"
            />
            <FrigateTextInput
              onChangeText={text => this.setState({ password: text })}
              label="PASSWORD"
              placeholder="PASSWORD"
              secureTextEntry
              value={this.state.password}
            />
            <TouchableOpacity
              onPress={() => {
                // Analytics.track('Forgot Password Pressed', { email: this.state.username });
                this.props.navigation.navigate('ForgotPassword');
                // Linking.openURL('http://thirdelement.herokuapp.com/users/password/new')
              }}
            >
              <View style={{ alignItems: 'flex-end', paddingRight: 20, paddingTop: 5 }}>
                <Text style={{ color: 'white' }}>Forgot Password?</Text>
              </View>
            </TouchableOpacity>
          </View>
        }
        {this.props.token &&
          <View style={styles.activityIndicator}>
            <ActivityIndicator size="large" />
          </View>
        }
        {!this.props.token &&
          <View style={styles.actionButtons}>
            <FrigateButton
              title="Log In"
              disabled={!_.every([
                this.state.username,
                this.state.password,
              ], Boolean)}
              onPress={this.loginPressed}
            />
          </View>
        }
        {Platform.OS === 'ios' &&
          <KeyboardSpacer />
        }
      </View>
    );
  }
}
LoginScreen.propTypes = {
  login: PropTypes.func.isRequired,
  navigation: PropTypes.shape({
    goBack: PropTypes.func,
  }).isRequired,
  token: PropTypes.string,
};
LoginScreen.defaultProps = {
  token: null,
};
LoginScreen.navigationOptions = props => ({
  title: 'Welcome Back',
  headerLeft: <HeaderBackButton onPress={() => props.navigation.goBack()} />,
  headerRight: <NavRightIcon />,
  headerStyle: {
    backgroundColor: 'black',
    shadowColor: 'transparent',
    borderBottomWidth: 0,
  },
  headerTintColor: Colors.thirdElementOrange,
  headerTitleStyle: {
    fontWeight: 'bold',
  },
});

const mapStateToProps = state => ({
  email: state.user.email,
  id: state.user.id,
  token: state.user.token,
  lessons: state.lessonModules.lessons,
  modules: state.lessonModules.modules,
  signedCurrentTerms: state.user.signedCurrentTerms,
});
const mapDispatchToProps = dispatch => ({
  login: (u, p) => dispatch(loginUser(u, p)),
  getModules: () => dispatch(getModuleInfo()),
  getLessons: () => dispatch(getLessonInfo()),
  getMeQuestions: () => dispatch(getMeQuestions()),
  getMeAnswers: () => dispatch(getMeAnswers()),
  pullOnLoadData: id => dispatch(pullOnLoadData(id)),
  setLoggingIn: value => dispatch(setLoggingIn(value)),
});
export default connect(
  mapStateToProps,
  mapDispatchToProps,
)(LoginScreen);

我进入Info.plist并配置为：

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
</dict>

这给了我另一个类似于这篇文章的错误：

反应原生中"不存在捆绑 URL"是什么意思？

我尝试通过这样做来遵循它的建议：

我跑rm -rf ios/build/; kill $(lsof -t -i:8081); react-native run-ios，但它什么也没做。

Answer 1

对于Android模拟器，您必须使用IP地址而不是本地主机。例如，使用：

fetch('http://000.000.000:3000/login', {
  method: 'POST',
  headers: {
    Accept: 'application/json',
    'Content-Type': 'application/json',
  },
  body: params,
})

您还必须允许 http://请求。打开 info.plist （ProjectFolder->ios->ProjectFolder->info.plist） 并在之前添加以下内容：

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
</dict>

请参阅： https://stackoverflow.com/a/48946478/10987825