Android：基本用户登录失败

晚上好

我试图创建一个简单的android应用程序，要求用户提供登录信息；其详细信息存储在SQL数据库中

但是，php会显示一个错误通知：未定义变量：用户名和通知：未定义变量：密码

protected String doInBackground**(String... arg0)** {

        try{
            **String username = (String)arg0[0];**
            **String password = (String)arg0[1];**

            String link="//Removed//";
            String data  = URLEncoder.encode("username", "UTF-8") + "=" + URLEncoder.encode(username, "UTF-8");
            data += "&" + URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8");

            URL url = new URL(link);
            URLConnection conn = url.openConnection();

            conn.setDoOutput(true);
            OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());

            wr.write( data );
            wr.flush();

            BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));

            StringBuilder sb = new StringBuilder();
            String line = null;

            // Read Server Response
            while((line = reader.readLine()) != null)
            {
                sb.append(line);
                break;
            }
            return sb.toString();
        }
        catch(Exception e){
            return new String("Exception: " + e.getMessage());
        }

}

我相信这个错误可以追溯到负责连接数据库的Java类。特别是字符串用户名和密码

protected String doInBackground**(String... arg0)** {

        try{
            **String username = (String)arg0[0];**
            **String password = (String)arg0[1];**

            String link="//Removed//";
            String data  = URLEncoder.encode("username", "UTF-8") + "=" + URLEncoder.encode(username, "UTF-8");
            data += "&" + URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8");

            URL url = new URL(link);
            URLConnection conn = url.openConnection();

            conn.setDoOutput(true);
            OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());

            wr.write( data );
            wr.flush();

            BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));

            StringBuilder sb = new StringBuilder();
            String line = null;

            // Read Server Response
            while((line = reader.readLine()) != null)
            {
                sb.append(line);
                break;
            }
            return sb.toString();
        }
        catch(Exception e){
            return new String("Exception: " + e.getMessage());
        }

}

因为我对android非常陌生，所以我一直在关注 引导以创建系统。我将非常感谢您对此事的任何帮助

多谢各位

PHP代码

 <?php
$con=mysqli_connect("//","//","//","//");

if (mysqli_connect_errno($con))
{
   echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

$username = $_POST['username'];

$password = $_POST['password'];


$result = mysqli_query($con,"SELECT Role FROM my_db WHERE 
Username='$username' and Password='$password'");


$row = mysqli_fetch_array($result);
$data = $row[0];

if($data){
echo $data;
}
mysqli_close($con);
?>

---

Hi，GET参数名称似乎不匹配。您也编写了php端吗？请确保两边使用相同的密钥。顺便说一句，通过URL发送凭据不是一个好主意。嗨，赛昂谢谢你的回复，php代码我使用网站上提供的模板，仅在我的SQL凭据中编辑。你也可以发布php代码吗？