Question

当我尝试比较if (responseJson === "wrong")时，它总是转到else，即使我发出警告，告诉我responseJson的值是“错误的”。以下是PHP文件和Form.js的代码

<?php
include("Config.php");

 $json = file_get_contents('php://input');

 $obj = json_decode($json,true);
 
$username = $obj['username'];
$password = $obj['password'];

$link = mysqli_connect("$HostName", "$HostUser", "$HostPass", "$DatabaseName");
if (!$link) {
die('Could not connect: ' . mysql_error());
}

$check = mysqli_query($link,"SELECT mail FROM Usuarios WHERE `mail`= '$username' AND `contrasena`= '$password'");

$numrows = mysqli_num_rows($check);
				if ($numrows == 0 )
				{
					$InvalidMSG = "wrong";
					trim($InvalidMSG);
					$InvalidMSGJSon = json_encode($InvalidMSG);
					
					echo($InvalidMSGJSon);
				}
else {
					//login user
					$row = mysqli_fetch_array($check);
					$mail = $row['mail'];
					$array = array('mail' => $mail); 
					$answer = json_encode($array);//"Login Done," . $mail;
					echo($answer);
}
mysqli_close($link);

import React from 'react';
import { StyleSheet, TouchableOpacity, TextInput, Text, View, Alert } from 'react-native';
import styles from './From.styles.js'


export default class Form extends React.Component {
constructor(props) {
     super(props)
     this.state = {
     UserEmail: '',
     UserPassword: ''
}
   

UserLoginFunction = () =>{
 const { UserEmail }  = this.state ;
 const { UserPassword }  = this.state ;
 const url = 'https://andrianodna.000webhostapp.com/Login.php'

fetch(url, {
  method: 'POST',
  headers: {
    'Accept': 'application/json',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({

    username: UserEmail,

    password: UserPassword
  })
})
      .then((response) => response.text())
      .then((responseJson) => {

      if(responseJson === "wrong")
        {
             //Alert.alert('E-Mail o Contraseña equivocados')
             Alert.alert(responseJson);
        }
        else{
          this.props.navigation.navigate('Router' , { Email:UserEmail});
          Alert.alert(responseJson);
        }
      })
      .catch((error) => {
        console.error(error);
      });
  }

  render() {
    return (

      <View style={styles.container}>
            <TextInput style ={styles.input}
            placeholder = 'E-Mail'
            onChangeText={UserEmail => this.setState({UserEmail})}
            placeholderTextColor="rgba(0,0,0,0.3)"
            keyboardType="email-address"
            underlineColorAndroid='rgba(0,0,0,0)'/>

            <TextInput style ={styles.input}
            placeholder = 'Contraseña'
            onChangeText={UserPassword => this.setState({UserPassword})}
            placeholderTextColor="rgba(0,0,0,0.3)"
            underlineColorAndroid='rgba(0,0,0,0)'
            secureTextEntry = {true} />

            <TouchableOpacity onPress={this.UserLoginFunction} style={styles.Button}>
             <Text style={styles.buttonText}>{this.props.type}</Text>
           </TouchableOpacity>
           <TouchableOpacity style={styles.Button2}>
            <Text style={styles.buttonText}>{this.props.type2}</Text>
          </TouchableOpacity>
          </View>
      );
  }
}

userEmail和userPassword为我提供了我想要的值，我只是想在前面说过的状态错误时不去Router.js。我尝试使用\ n和\ r在不同的组合上。还有“==”而不是“===”。

Answer 1

您从服务器（"wrong"）收到的值在开头有\r\n，这就是条件失败的原因。我试过responseJson === '\r\n"wrong"'（非常有线），条件是true。请注意"也是返回字符串的一部分。

希望这会有所帮助！

responseJson比较总是输错了

1 个答案: