Question

好的，我已经完成了上述任务，但我对此并不满意。它看起来非常复杂。

我需要一些其他方法来解决这个问题，因为我在Android开发方面的经验非常少，而且无法找到其他任何方式。

在这里我是如何做到的。我将向您展示访问数据库的简单登录系统。

以下是登录活动。

package com.example.andorid.ersnexus.userlogin;

import android.app.Activity;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
mport android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.example.andorid.ersnexus.R;
import
com.example.andorid.ersnexus.userprofile.homeactivity.
UserProfileHomeActivity;
import com.example.andorid.ersnexus.usersignup.UserSignUpActivity;
import com.example.andorid.ersnexus.util.SharedPreferencesData;
import com.example.andorid.ersnexus.webservices.BackgroundDbConnector;


//This is the main activity of the app.
//It is the user login screen where users logs in or sign up's.

public class UserLoginActivity extends AppCompatActivity {

private EditText mUserName;
private EditText mUserPassword;
private Button mLoginButton;
private Button mSignUpButton;
//private UserBaseHelper mHelper;
private String userName;
private String pass;
//private String password;
//private String mErno;
public static Activity mActivity;
public static Boolean mActive;

@Override
public void onCreate (Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_user_login);

    mActivity = this;

    Boolean status = SharedPreferencesData.getStoredLoginStatus(UserLoginActivity.this);
    if(status){
        Intent i = new Intent(UserLoginActivity.this, UserProfileHomeActivity.class);
        startActivity(i);
    }

    //mHelper = new UserBaseHelper(this);


    //user UserName editText in activity_user_login
    mUserName = (EditText) findViewById(R.id.login_user_name);


    //PASSWORD editText
    mUserPassword = (EditText) findViewById(R.id.login_user_pass);


    //SignUp button
    mSignUpButton = (Button) findViewById(R.id.sign_up_button);
    mSignUpButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick (View v) {
            Intent i = new Intent(UserLoginActivity.this, UserSignUpActivity.class);
            startActivity(i);

        }
    });


    //Login Button
    mLoginButton = (Button) findViewById(R.id.login_button);
    mLoginButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick (View v) {
            if(isNetworkAvailableAndConnected()) {
                /*try {
                    if(!InetAddress.getByName("192.168.2.3").isReachable(5000)){
                        throw new Exception("Host does not exist::");
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                    Toast.makeText(UserLoginActivity.this,
                            "Server Is Down",Toast.LENGTH_SHORT).show();
                }*/
                String type = "login";
                userName = mUserName.getText().toString();
                pass = mUserPassword.getText().toString();
                //password = mHelper.fetchUserPass(userName);
               //mErno = mHelper.fetchErNo(userName);
                //String fullName = mHelper.fetchFullName(userName);

                ***BackgroundDbConnector backgroundDbConnector = new
                        BackgroundDbConnector(UserLoginActivity.this);
                backgroundDbConnector.execute(type, userName, pass);***

                SharedPreferencesData.setStoredUsername(UserLoginActivity.this, userName);
            }else {
                Toast.makeText(UserLoginActivity.this,
                        "No Internet Connection",Toast.LENGTH_SHORT).show();
            }

        }
    });

}

@Override
public void onStart() {
    super.onStart();
    mActive = true;
}

@Override
public void onStop() {
    super.onStop();
    mActive = false;
}

private boolean isNetworkAvailableAndConnected () {
    ConnectivityManager cm = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);

    boolean isNetworkAvailable = cm.getActiveNetworkInfo() != null;

    return isNetworkAvailable &&
            cm.getActiveNetworkInfo().isConnected();
}

}

Post请求通过backgroundTask发送

BackgroundDbConnector backgroundDbConnector = new
                        BackgroundDbConnector(UserLoginActivity.this);

backgroundDbConnector.execute(type, userName, pass);

然后在backGround AsyncTask中发生以下事情：

 try {
                //Fetch the username and password from the background method call.
                String username = params[1];
                String password = params[2];

                mHttpURLConnection = URLManager.
                        getConnection(URLManager.LOGIN_URL);

                //Creating the outputStream
                OutputStream outputStream = mHttpURLConnection.getOutputStream();
                //Writing in the outputStream.
                BufferedWriter bufferedWriter = new BufferedWriter(new
                        OutputStreamWriter(outputStream, "UTF-8"));

                //This is for connecting the variables in the app and in the php file.
                String postData = URLEncoder.encode("username", "UTF-8") + "=" +//$_POST["username"]
                        URLEncoder.encode(username, "UTF-8") + "&" +
                        URLEncoder.encode("password", "UTF-8") + "=" +//$_POST["password"]
                        URLEncoder.encode(password, "UTF-8");

                //Feeding the data.
                bufferedWriter.write(postData);
                bufferedWriter.flush();
                bufferedWriter.close();
                outputStream.close();

                //Creating an inputStream to fetch the results.
                InputStream inputStream = mHttpURLConnection.getInputStream();

                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(
                        inputStream, "iso-8859-1"));

                //Getting the results
                String result = "";
                String line;
                while ((line = bufferedReader.readLine()) != null) {
                    result += line;
                }
                bufferedReader.close();
                inputStream.close();
                mHttpURLConnection.disconnect();
                //Returning the results
                return result;
}

最后php文件如下：

<?php
require "conn.php";

$user_name = $_POST["username"];
$user_pass = $_POST["password"];

$mysql_qry = "SELECT * FROM student_data WHERE username='$user_name' AND 
password='$user_pass';";

$result = mysqli_query($conn, $mysql_qry);
$row_cnt = mysqli_num_rows($result);

if($row_cnt > 0){
$row = mysqli_fetch_assoc($result);
$erno = $row["enrollmentnumber"];
echo $erno;
} 
else{
echo "Wrong Username or Password";
}
?>

所以大多数数据库连接都以这种方式完成，我需要一些其他的方法来完成这个

我有一种直觉，你可以看到backGround任务需要以其他方式处理，但我没有得到...

那些在Android方面有良好经验的人，请引导我走正确的道路。

感谢那些花时间阅读我的代码的开发人员。

这是我对该项目的链接。如果你愿意，请看看并测试，我会喜欢关于我的代码的意见。

https://github.com/shrungBhatt/ErNexus

Answer 1

嗯，我找到了另一种选择，实施它非常可爱。

try {
            //Fetch the username and password from the background method call.
            String username = params[1];
            String password = params[2];

            mHttpURLConnection = URLManager.
                    getConnection(URLManager.LOGIN_URL);

            //Creating the outputStream
            OutputStream outputStream = mHttpURLConnection.getOutputStream();
            //Writing in the outputStream.
            BufferedWriter bufferedWriter = new BufferedWriter(new
                    OutputStreamWriter(outputStream, "UTF-8"));

            //This is for connecting the variables in the app and in the php file.
            String postData = URLEncoder.encode("username", "UTF-8") + "=" +//$_POST["username"]
                    URLEncoder.encode(username, "UTF-8") + "&" +
                    URLEncoder.encode("password", "UTF-8") + "=" +//$_POST["password"]
                    URLEncoder.encode(password, "UTF-8");

            //Feeding the data.
            bufferedWriter.write(postData);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();

            //Creating an inputStream to fetch the results.
            InputStream inputStream = mHttpURLConnection.getInputStream();

            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(
                    inputStream, "iso-8859-1"));

            //Getting the results
            String result = "";
            String line;
            while ((line = bufferedReader.readLine()) != null) {
                result += line;
            }
            bufferedReader.close();
            inputStream.close();
            mHttpURLConnection.disconnect();
            //Returning the results
            return result;
}

使用Volley将以上所有代码替换为以下代码。 以下是新代码

StringRequest stringRequest = new StringRequest(Request.Method.POST, URLManager.
                        LOGIN_URL, new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        if (response != null &&
                                !response.equals("Wrong Username or Password")) {
                            SharedPreferencesData.setStoredLoginStatus(mContext, true);
                            SharedPreferencesData.setStoredErno(mContext, response);
                            mContext.startActivity(new Intent(mContext,
                                    UserProfileHomeActivity.class));
                        } else {
                            Toast.makeText(mContext, "Wrong Username or Password!",
                                    Toast.LENGTH_SHORT)
                                    .show();
                        }
                    }
                }, new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(UserLoginActivity.this, error.toString(),
                                Toast.LENGTH_SHORT).show();

                    }
                }) {
                    @Override
                    protected Map<String, String> getParams() {
                        Map<String, String> params = new HashMap<>();
                        params.put(KEY_USERNAME, userName);
                        params.put(KEY_PASSWORD, pass);
                        return params;
                    }
                };

                SharedPreferencesData.setStoredUsername(UserLoginActivity.this, userName);

                RequestQueue requestQueue = Volley.newRequestQueue(UserLoginActivity.this);
                requestQueue.add(stringRequest);

在android

1 个答案: