无法在Android Studio中使用PHP从MySQL数据库中获取数据

时间：2016-09-13 03:05:43

标签： php android mysql android-studio

我正在进行移动应用程序的登录和注册子系统，我是通过关注youtube教程视频完成的，注册功能运行良好，因为所有数据都已成功存储在数据库中。

但是当我尝试使用已创建的用户名登录时，它会显示一条消息＆＃34;用户名和密码不存在！＆＃34;，AS不会返回任何错误消息。我检查过所有的编码几次，谷歌搜索答案，但我找不到任何，提前谢谢！ =）

**现在我确定我的活动没有任何问题，但是php脚本文件

的LocalDB 

public class LocalDb {
public static final String SP_Name = "UserInfo";
SharedPreferences localDb;

//Constructor
public LocalDb(Context context)
{
    localDb = context.getSharedPreferences(SP_Name,0);
}

//store user data
public void storeData(Contact contact)
{
    SharedPreferences.Editor editor = localDb.edit();
    editor.putString("Username",contact.username);
    editor.putString("Email",contact.email);
    editor.putString("Student_ID",contact.student_id);
    editor.putString("Password",contact.password);
    editor.commit();
}

//get information about which user is currently logged in
public Contact getLoggedInUser()
{
    String username=localDb.getString("Username","");
    String email=localDb.getString("Email","");
    String student_id=localDb.getString("Student_ID","");
    String password=localDb.getString("Password","");

    Contact storedContact=new Contact(username,email,student_id,password);
    return storedContact;
}

public void setUserLoggedIn(boolean loggedIn)
{
    SharedPreferences.Editor editor=localDb.edit();
    editor.putBoolean("loggedIn",loggedIn);
    editor.commit();
}

//Tell user whether is currently login
public Boolean getUserLoggedIn()
{
    if(localDb.getBoolean("loggedIn",false))
        return true;
    else
        return false;
}
//Clear data when a user log out
public void clearData(){
    SharedPreferences.Editor editor = localDb.edit();
    editor.clear();
    editor.commit();
}
}

以下是php文件：

Register.php 

<?php
$con = mysqli_connect("localhost" , "my_db_name" , "my_password" , "my_db");

$username = $_POST["Username"];
$email = $_POST["Email"];
$student_id = $_POST["Student_ID"];
$password = $_POST["Password"];

$insertquery = mysqli_prepare($con , "INSERT INTO UserDetails (Username , Email , Student_ID , Password ) VALUES (? , ? , ? , ?)");
mysqli_stmt_bind_param($insertquery , "ssss" , $username , $email , $student_id , $password);
mysqli_stmt_execute($insertquery);

mysqli_stmt_close($insertquery);

mysqli_close($con);

?>

getUserData.php 

<?php
$con = mysqli_connect("localhost" , "my_db_name" , "my_password" , "my_db");

$username = $_POST["Username"];
$password = $_POST["Password"];

$selectquery = mysqli_prepare($con , "SELECT * FROM UserDetails WHERE Username= ? AND Password= ?");
mysqli_stmt_bind_param($selectquery , "ss" , $username , $password);
mysqli_stmt_execute($selectquery);

mysqli_stmt_store_result($selectquery);
mysqli_stmt_bind_result($selectquery , $username , $email , $student_id , $password);

$user=array();

while(mysqli_stmt_fetch($selectquery);  
(
    $user[username] = $username;
    $user[email] = $email;
    $user[student_id] = $student_id;
    Suser[password] = $password;
)
echo json_encode($user);

mysqli_stmt_close($selectquery);
mysqli_close($con);

?>

1 个答案:

答案 0 :(得分：0)

我当然无法理解您的代码，但尝试使用新的Networking Lib。（“Volley”）进行通话。我登录和注册的例子。 

//Layout of Activity
<?xml version="1.0" encoding="utf-8"?>
<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:padding="2dp"
tools:context="com.test.test.ScreenOne">


<EditText
    android:layout_width="240dp"
    android:layout_height="wrap_content"
    android:id="@+id/etUsername"
    android:layout_marginTop="150dp"
    android:hint="username"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true" />

<EditText
    android:layout_width="240dp"
    android:layout_height="wrap_content"
    android:id="@+id/etPassword"
    android:hint="password"
    android:layout_below="@+id/etUsername"
    android:layout_centerHorizontal="true" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Login"
    android:id="@+id/bLogin"
    android:layout_below="@+id/etPassword"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="50dp" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Save"
    android:id="@+id/bSave"
    android:layout_below="@+id/bLogin"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="42dp" />
</RelativeLayout>

Activity有2个按钮和2个EditText，登录按钮通过服务器登录，Save按钮将数据保存在服务器中：

package com.test.test;

import android.app.ProgressDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;

import java.util.HashMap;
import java.util.Map;

public class ScreenOne extends AppCompatActivity {

private static final String URL_LOGIN = "http://IP_ADDRESS/login.php";
private static final String URL_SAVE = "http://IP_ADDRESS/save.php";
private EditText username;
private EditText password;
private Button login;
Button save;
String name;
String pass;

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

    username = (EditText) findViewById(R.id.etUsername);
    password = (EditText) findViewById(R.id.etPassword);

    (login = (Button) findViewById(R.id.bLogin)).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            request();
        }
    });

    (save = (Button) findViewById(R.id.bSave)).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            saveRequest();
        }
    });
}

private void saveRequest() {
    name = username.getText().toString().trim();
    pass = password.getText().toString().trim();
    final ProgressDialog mDialog = new ProgressDialog(this);
    mDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
    mDialog.setMessage("Loading...");
    mDialog.show();

    StringRequest request = new StringRequest(Request.Method.POST, URL_SAVE,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    mDialog.dismiss();
                    Toast.makeText(ScreenOne.this, response, Toast.LENGTH_LONG).show();
                    username.setText("");
                    password.setText("");
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    mDialog.dismiss();
                    Toast.makeText(ScreenOne.this, "Something went wrong", Toast.LENGTH_LONG).show();
                }
            }){
        @Override
        protected Map<String, String> getParams() throws AuthFailureError {
            Map<String, String> key = new HashMap<>();
            key.put("username", name);
            key.put("password", pass);
            return key;
        }
    };

    NetworkCalls.getInstance().addToRequestQueue(request);
}

private synchronized void request() {
    name = username.getText().toString().trim();
    pass = password.getText().toString().trim();
    final ProgressDialog mDialog = new ProgressDialog(this);
    mDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
    mDialog.setMessage("Loading...");
    mDialog.show();

    StringRequest request = new StringRequest(Request.Method.POST, URL_LOGIN,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    mDialog.dismiss();
                    Toast.makeText(ScreenOne.this, response, Toast.LENGTH_LONG).show();
                    username.setText("");
                    password.setText("");
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    mDialog.dismiss();
                    Toast.makeText(ScreenOne.this, "Something went wrong", Toast.LENGTH_LONG).show();
                }
            }){
        @Override
        protected Map<String, String> getParams() throws AuthFailureError {
            Map<String, String> key = new HashMap<>();
            key.put("username", name);
            key.put("password", pass);
            return key;
        }
    };

    NetworkCalls.getInstance().addToRequestQueue(request);
 }
}

Volley请求的Singleton类：

import android.content.Context;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.toolbox.Volley;

/**
 * Created by W4R10CK on 12-09-2016.
 */
public class NetworkCalls {
    private RequestQueue requestQueue;
    private static Context context;

    private static NetworkCalls ourInstance = new NetworkCalls();

    public static NetworkCalls getInstance() {
        return ourInstance;
    }

    private NetworkCalls() {
    }

    public RequestQueue getRequestQueue(){
        requestQueue = Volley.newRequestQueue(context.getApplicationContext());
        return requestQueue;
    }

    public <T> void addToRequestQueue(Request<T> request){
        getRequestQueue().add(request);
    }
}

调用服务器的API：

 //conn.php for connection (file one)
<?php
$host = "localhost";
$user = "root";
$pass = "";
$db_name = "hello";

$con = new mysqli($host,$user,$pass,$db_name);

if($con -> connect_error){
echo "Connection error";
}   


//save.php(file two)
<?php
$username = $_POST['username'];
$password = $_POST['password'];
require_once('conn.php');

$sql = "INSERT INTO user (username, password) VALUES ('$username','$password')";

if($con -> query($sql) === TRUE) {
echo "User added";
}
//$con -> close();
?>
?>

//login.php(file three)
<?php
require_once('conn.php');

$username = $_POST['username'];
$password = $_POST['password'];

$sql = "SELECT * FROM user WHERE username = '$username' AND password = '$password'";

$result = mysqli_query($con,$sql);

if(mysqli_fetch_array($result) == NULL){
echo "Invalid Cred.";
}else{
echo "Success";
}

$con->close();
?>

最后在localhost 用户中创建一个名为 hello 的数据库，其中包含2个字段用户名，密码。< / p>

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