react native iOS-nsnull类型的JSON值' '无法转换为有效的url

Question

每次插入新邮件和密码后，我都会通过expo通过应用程序注册到应用程序，每次都会显示此屏幕。this is the screen error

即使我关闭了博览会后再次打开，它也会显示带有消息的相同红色屏幕。但是，如果我关闭该项目（通过摇动刷新它）并再次输入整个项目，那么现在该用户已经存在并且可以完美运行……（仍然需要修复）。

---

这是** Register.js页面代码：**

import React, { Component } from "react";
import { View, Button, StyleSheet, TextInput, Alert, AsyncStorage } from "react-native";

const URL = 'http://185.60.170.14/plesk-site-preview/ruppinmobile.ac.il/site17/WebService.asmx';

export default class Register extends Component {
  state = {
    email: "",
    password: "",
    repassword: ""
  };

  Register = () => {
    if(this.state.password != this.state.repassword){
      Alert.alert(
        "Error",
        'Password does not match',
        [{ text: "OK", onPress: () => null }],
        { cancelable: false }
      );
      this.setState({password: '', repassword: ''});
      return;
    }


    let data = {
      email: this.state.email,
      password: this.state.password
    };

    fetch(URL + "/Register", {
      // בקשה לשרת למתודה Register
      body: JSON.stringify(data), // שליחת פרמטרים
      method: "POST",
      headers: {
        "Content-type": "application/json; charset=UTF-8"
      }
    })
      .then(res => {
        return res.json();
      })
      .then(userData => {
        console.log(userData.d);
        
        if (userData.d == "Error: This email is already in use") {
          Alert.alert(
            "Error",
            userData.d,
            [{ text: "OK", onPress: () => null }],
            { cancelable: false }
          );
        } else {
          AsyncStorage.setItem("@KnowingFriends:user", userData.d);
          this.props.navigation.navigate("MainApp");
        }
      })
      .catch(err => {
        console.error(err);
      });
  };

  render() {
    return (
      <View style={styles.container}>
        <TextInput
          style={styles.input}
          onChangeText={text => this.setState({ email: text })}
          value={this.state.email}
          placeholder="Email"
        />

        <TextInput
          style={styles.input}
          onChangeText={text => this.setState({ password: text })}
          value={this.state.password}
          secureTextEntry={true}
          placeholder="Password"
        />

        <TextInput
          style={styles.input}
          onChangeText={text => this.setState({ repassword: text })}
          value={this.state.repassword}
          secureTextEntry={true}
          placeholder="Repeat Password"
        />

        <Button onPress={this.Register} title="Submit" color="#841584" />
        <Button
          onPress={() => {
            this.props.navigation.navigate("Login");
          }}
          title="Go back"
          color="#841584"
        />
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: "#fff",
    alignItems: "center",
    justifyContent: "center"
  },
  input: {
    height: 40,
    width: 300,
    borderColor: "gray",
    borderWidth: 1
  }
});

如何解决此问题？

Answer 1

我也是同样的问题，但我已经解决了

state = {
    text: '',
    image: null,
  };

已更改

state = {
text: '',
image: '',
  };