php - 使用 PHP 和 MySQL 的 Android 注册表单

Question

我将创建一个简单的注册表单应用程序，当用户插入用户名和密码时，用户界面中的EditText会显示<数据库中记录的strong>id。

我的应用程序正确地将用户插入数据库；只是我的 EditText 不显示 id ...

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#00aeef"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<TextView
    android:id="@+id/textView3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="50dp"
    android:layout_marginTop="18dp"
    android:text="Register Example"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textColor="#ffffff" />

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignTop="@+id/textView3"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="45dp"
    android:text="Username:"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textColor="#ffffff" />

<EditText
    android:id="@+id/edt_username"
    android:layout_width="250dp"
    android:layout_height="40dp"
    android:layout_below="@+id/textView3"
    android:layout_centerHorizontal="true"
    android:background="#ffffff"
    android:ems="10"
    android:padding="5dp" >

    <requestFocus />
</EditText>

<Button
    android:id="@+id/btn_insert"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/edt_result"
    android:layout_below="@+id/edt_password"
    android:layout_marginTop="16dp"
    android:background="#ffffff"
    android:text="Insert"
    android:textColor="#00aeef" />

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignRight="@+id/textView1"
    android:layout_below="@+id/edt_username"
    android:text="Password:"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textColor="#ffffff" />

<EditText
    android:id="@+id/edt_password"
    android:layout_width="250dp"
    android:layout_height="40dp"
    android:layout_alignLeft="@+id/edt_username"
    android:layout_below="@+id/textView2"
    android:background="#ffffff"
    android:ems="10"
    android:padding="5dp" />

<EditText
    android:id="@+id/edt_result"
    android:layout_width="match_parent"
    android:layout_height="40dp"
    android:layout_below="@+id/btn_insert"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="22dp"
    android:background="#ffffff"
    android:ems="10"
    android:padding="5dp" />

</RelativeLayout>

InsertClass.java

package com.example.testphp;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;

public class InsertClass extends AsyncTask<String, Void, String>{

private Context context;
private ProgressDialog pDialog;
private EditText edt;
private String json = "";   
private JSONObject jObj = null;

public InsertClass(Context context, EditText edt)
{
    this.context = context;
    pDialog = new ProgressDialog(context);
    this.edt = edt;
}

@Override
protected void onPreExecute() {
    pDialog.setMessage("Loading... Please wait");
    pDialog.show();
    super.onPreExecute();
}

@Override
protected String doInBackground(String... arg0) {

    try
    {
    String username = (String)arg0[0];
    String password = (String)arg0[1];
    String link = "http://10.0.2.2:8020/test/test.php";
    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;
    while((line = reader.readLine()) != null)
    {
        sb.append(line);
        break;
    }
    json = sb.toString();
    jObj = new JSONObject(json);
    edt.setText(jObj.getString("id"));
    return sb.toString();
    }
    catch(JSONExeption e)
    {
        return new String("Exeption: " + e.getMessage());
    }
    catch(Exception e)
    {
        return new String("Exeption: " + e.getMessage());
    }
}

@Override
protected void onPostExecute(String result) {
    pDialog.dismiss();
    super.onPostExecute(result);
}
}

MainActivity.java

package com.example.testphp;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {

String username;
String password;
EditText edtUsername;
EditText edtPassword;
EditText edtResult;
Button btnInsert;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    btnInsert = (Button) findViewById(R.id.btn_insert);
    edtPassword = (EditText) findViewById(R.id.edt_password);
    edtUsername = (EditText) findViewById(R.id.edt_username);
    edtResult = (EditText) findViewById(R.id.edt_result);

    btnInsert.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {

            username = edtUsername.getText().toString();
            password = edtPassword.getText().toString();
            new InsertClass(MainActivity.this, edtResult).execute(username,password);

        }
    });

}

    @Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}

测试.PHP

<?php

$con = mysqli_connect("localhost" , "root" , "","test");
if(mysqli_connect_errno($con))
{
echo "Failed to connect to MySQL: " . mysqli_connect_errno();
} 
$username = $_POST['username'];
$password = $_POST['password'];

$result = mysqli_query($con,"INSERT INTO test (username,pass) VALUES '$username','$password')");
if($result)
{
$id_result = mysqli_query($con,"SELECT id FROM test WHERE username = $username");
if($id_result)
{
$response = array("id" => $id_result);
echo json_encode($response);
}
}
mysqli_close($con);
?>

任何建议，我们将不胜感激......

Answer 1

据我所知，您的 SQL 中有 2 个错误。

该行缺少括号:

$result = mysqli_query($con,"INSERT INTO test (username,pass) VALUES  '$username','$password')");
                                                                     ^ bracket

应该读作:

$result = mysqli_query($con,"INSERT INTO test (username,pass) VALUES ('$username','$password')");

此行缺少 $username 的引号

$id_result = mysqli_query($con,"SELECT id FROM test WHERE username = $username");

应该读作:

$id_result = mysqli_query($con,"SELECT id FROM test WHERE username = '$username'");

将or die(mysqli_error($con))添加到mysqli_query()以查看实际错误。

您还应该防止 SQL 注入(inject)，将 POST 变量更改为:

$username = stripslashes($_POST['username']);
$username = mysqli_real_escape_string($con, $_POST['username']);

$password = stripslashes($_POST['password']);
$password = mysqli_real_escape_string($con, $_POST['password']);

查看mysqli with prepared statements ，或PDO with prepared statements ，它们更安全。

我无法帮助您处理 Android 代码，但请参阅 Selvin 在评论中提到的内容:

"you are catching an exception and do nothing with it (do at least e.printStackTrace() to see it in Logcat) ... and i'm pretty sure that you are hurting UI with bad touch, UI doesn't like to be touched from not UI thread"