Android 用户-注册，登录和注销

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📜 Android 用户-注册，登录和注销

📅 最后修改于: 2020-10-11 05:54:29 🧑 作者: Mango

排球库-注册，登录和注销

在本教程中，我们将使用Volley库和JSON创建基本的用户注册和登录模块。 Volley是一个HTTP库，它为我们的应用程序提供了网络连接功能。

使用Volley库的优点如下：

更轻松，更快的请求管理。
提供有效的网络管理。

对于服务器端数据处理，我们使用带有XAMPP服务器的PHP和MySQL进行数据处理。

在创建Android应用程序模块之前，让我们首先创建服务器端数据处理API代码，以便在PHP和MySQL中进行注册和登录。

1.创建一个名称为registerlogin和表users的数据库，其中包含以下字段。

2.在C：\ xampp \ htdocs \ androidphpmysql目录下，使用PHP和数据库编写以下连接建立代码。

在androidphpmysql(您的项目位置)目录中，创建一个connection.php文件并编写以下代码。

connection.php

connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
?>

3.在androidphpmysql目录中创建一个registrationapi.php文件，并编写以下代码。该文件处理来自Android应用程序的请求，并以JSON数组的形式生成对Android应用程序的响应。

registrationapi.php

prepare("SELECT id FROM users WHERE username = ? OR email = ?");
 $stmt->bind_param("ss", $username, $email);
 $stmt->execute();
 $stmt->store_result();
 
 if($stmt->num_rows > 0){
 $response['error'] = true;
 $response['message'] = 'User already registered';
 $stmt->close();
 }
 else{
 $stmt = $conn->prepare("INSERT INTO users (username, email, password, gender) VALUES (?, ?, ?, ?)");
 $stmt->bind_param("ssss", $username, $email, $password, $gender);
 
 if($stmt->execute()){
 $stmt = $conn->prepare("SELECT id, id, username, email, gender FROM users WHERE username = ?"); 
 $stmt->bind_param("s",$username);
 $stmt->execute();
 $stmt->bind_result($userid, $id, $username, $email, $gender);
 $stmt->fetch();
 
 $user = array(
 'id'=>$id, 
 'username'=>$username, 
 'email'=>$email,
 'gender'=>$gender
 );
 
 $stmt->close();
 
 $response['error'] = false; 
 $response['message'] = 'User registered successfully'; 
 $response['user'] = $user; 
 }
 }
 
}
else{
 $response['error'] = true; 
 $response['message'] = 'required parameters are not available'; 
}
break; 
case 'login':
  if(isTheseParametersAvailable(array('username', 'password'))){
 $username = $_POST['username'];
  $password = md5($_POST['password']); 
 
$stmt = $conn->prepare("SELECT id, username, email, gender FROM users WHERE username = ? AND password = ?");
 $stmt->bind_param("ss",$username, $password);
  $stmt->execute();
 $stmt->store_result();
 if($stmt->num_rows > 0){
 $stmt->bind_result($id, $username, $email, $gender);
 $stmt->fetch();
 $user = array(
 'id'=>$id, 
 'username'=>$username, 
 'email'=>$email,
 'gender'=>$gender
 );
 
 $response['error'] = false; 
 $response['message'] = 'Login successfull'; 
 $response['user'] = $user; 
 }
 else{
 $response['error'] = false; 
 $response['message'] = 'Invalid username or password';
 }
}
break; 
default: 
 $response['error'] = true; 
 $response['message'] = 'Invalid Operation Called';
}
}
else{
 $response['error'] = true; 
 $response['message'] = 'Invalid API Call';
}
echo json_encode($response);
function isTheseParametersAvailable($params){
foreach($params as $param){
 if(!isset($_POST[$param])){
 return false; 
  }
}
return true; 
}
?>

要检查您的PHP API是否正常运行，可以使用REST客户端(例如Postman工具)。

要检查API的注册代码，可以使用参数传递注册URL。

同样，您可以通过传递带有有效参数的登录URL来检查登录操作。

现在，在Android应用程序中，我们将创建三个活动类用于用户注册，用户登录并在主要活动中显示用户详细信息(作为配置文件)。

在布局中创建一个activity_main.xml并添加以下代码。此活动用于将用户的详细信息显示为配置文件。

activity_main.xml

现在，使用以下代码在布局目录中创建一个activity_login.xml文件。此活动用于用户登录UI。

activity_login.xml

使用以下代码在布局目录中创建一个activity_register.xml文件。此活动用于用户注册UI。

activity_register.xml

在build.gradle文件中添加volley库依赖项。

build.gradle

implementation 'com.android.volley:volley:1.0.0'

使用以下代码创建一个名为User.java的数据模型类。

User.java

package example.javatpoint.com.volleyregistrationloginsystem;


public class User {
    private int id;
    private String name, email, gender;

    public User(int id, String name, String email, String gender) {
        this.id = id;
        this.email = email;
        this.gender = gender;
        this.name = name;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }


    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }
}

我们需要定义调用服务器端API的URL。

创建一个URLs.java类并定义URL。

URLs.java

package example.javatpoint.com.volleyregistrationloginsystem;

public class URLs {
    private static final String ROOT_URL = "http://192.168.1.35/androidphpmysql/registrationapi.php?apicall=";
    public static final String URL_REGISTER = ROOT_URL + "signup";
    public static final String URL_LOGIN= ROOT_URL + "login";
}

VolleySingleton.java

package example.javatpoint.com.volleyregistrationloginsystem;

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

public class VolleySingleton {
    private static VolleySingleton mInstance;
    private RequestQueue mRequestQueue;
    private static Context mCtx;

    private VolleySingleton(Context context) {
        mCtx = context;
        mRequestQueue = getRequestQueue();
    }

    public static synchronized VolleySingleton getInstance(Context context) {
        if (mInstance == null) {
            mInstance = new VolleySingleton(context);
        }
        return mInstance;
    }

    public RequestQueue getRequestQueue() {
        if (mRequestQueue == null) {
            // getApplicationContext() is key, it keeps you from leaking the
            // Activity or BroadcastReceiver if someone passes one in.
            mRequestQueue = Volley.newRequestQueue(mCtx.getApplicationContext());
        }
        return mRequestQueue;
    }

    public  void addToRequestQueue(Request req) {
        getRequestQueue().add(req);
    }
}

创建一个名为SharedPreferences.java的类。在此类中，我们使用SharedPreferences类存储用户详细信息。 SharedPreferences类包含具有以下功能的四个方法：

userLogin()：此方法用于在登录后将用户信息存储在SharedPreferences中。
isLoggedIn()：此方法检查用户是否已经登录。
getUser()：此方法在登录时获取用户信息。
logout()：此方法清除SharedPreferences数据并使用户注销。

SharedPrefManager.java

package example.javatpoint.com.volleyregistrationloginsystem;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;

public class SharedPrefManager {

    private static final String SHARED_PREF_NAME = "volleyregisterlogin";
    private static final String KEY_USERNAME = "keyusername";
    private static final String KEY_EMAIL = "keyemail";
    private static final String KEY_GENDER = "keygender";
    private static final String KEY_ID = "keyid";
    private static SharedPrefManager mInstance;
    private static Context ctx;

    private SharedPrefManager(Context context) {
        ctx = context;
    }
    public static synchronized SharedPrefManager getInstance(Context context) {
        if (mInstance == null) {
            mInstance = new SharedPrefManager(context);
        }
        return mInstance;
    }

    //this method will store the user data in shared preferences
    public void userLogin(User user) {
        SharedPreferences sharedPreferences = ctx.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putInt(KEY_ID, user.getId());
        editor.putString(KEY_USERNAME, user.getName());
        editor.putString(KEY_EMAIL, user.getEmail());
        editor.putString(KEY_GENDER, user.getGender());
        editor.apply();
    }

    //this method will checker whether user is already logged in or not
    public boolean isLoggedIn() {
        SharedPreferences sharedPreferences = ctx.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE);
        return sharedPreferences.getString(KEY_USERNAME, null) != null;
    }

    //this method will give the logged in user
    public User getUser() {
        SharedPreferences sharedPreferences = ctx.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE);
        return new User(
                sharedPreferences.getInt(KEY_ID, -1),
                sharedPreferences.getString(KEY_USERNAME, null),
                sharedPreferences.getString(KEY_EMAIL, null),
                sharedPreferences.getString(KEY_GENDER, null)
        );
    }

    //this method will logout the user
    public void logout() {
        SharedPreferences sharedPreferences = ctx.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.clear();
        editor.apply();
        ctx.startActivity(new Intent(ctx, LoginActivity.class));
    }
}

现在，在MainActivity.java类中，如果用户已登录，我们将显示用户信息，否则，它将重定向到LoginActivity.java类。单击按钮时，将使用onClick()方法注销用户。

MainActivity.java

package example.javatpoint.com.volleyregistrationloginsystem;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    TextView id,userName,userEmail,gender;
    Button btnLogout;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if(SharedPrefManager.getInstance(this).isLoggedIn()){
            id = findViewById(R.id.textViewId);
            userName = findViewById(R.id.textViewUsername);
            userEmail = findViewById(R.id.textViewEmail);
            gender = findViewById(R.id.textViewGender);
            btnLogout = findViewById(R.id.buttonLogout);
            User user = SharedPrefManager.getInstance(this).getUser();

            id.setText(String.valueOf(user.getId()));
            userEmail.setText(user.getEmail());
            gender.setText(user.getGender());
            userName.setText(user.getName());

            btnLogout.setOnClickListener(this);
        }
        else{
            Intent  intent = new Intent(MainActivity.this,LoginActivity.class);
            startActivity(intent);
            finish();
        }
    }
    public void onClick(View view){
        if(view.equals(btnLogout)){
            SharedPrefManager.getInstance(getApplicationContext()).logout();
        }
    }
}

在LoginActivity.java类中，我们检查用户是否已经登录，如果为true，则重定向到MainActivity.java类，否则，允许用户登录。

Volley库的StringRequest类用于网络模块。 StringReuest类的对象采用请求方法类型，URL和响应的参数。

LoginActivity.java

package example.javatpoint.com.volleyregistrationloginsystem;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.ProgressBar;
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 org.json.JSONException;
import org.json.JSONObject;
import java.util.HashMap;
import java.util.Map;

public class LoginActivity extends AppCompatActivity {
    EditText etName, etPassword;
    ProgressBar progressBar;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        if (SharedPrefManager.getInstance(this).isLoggedIn()) {
            finish();
            startActivity(new Intent(this, MainActivity.class));
        }

        progressBar = findViewById(R.id.progressBar);
        etName = findViewById(R.id.etUserName);
        etPassword = findViewById(R.id.etUserPassword);


        
        //calling the method userLogin() for login the user
        findViewById(R.id.btnLogin).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                userLogin();
            }
        });

        //if user presses on textview not register calling RegisterActivity
        findViewById(R.id.tvRegister).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                finish();
                startActivity(new Intent(getApplicationContext(), RegisterActivity.class));
            }
        });
    }

    private void userLogin() {
        //first getting the values
        final String username = etName.getText().toString();
        final String password = etPassword.getText().toString();
        //validating inputs
        if (TextUtils.isEmpty(username)) {
            etName.setError("Please enter your username");
            etName.requestFocus();
            return;
        }

        if (TextUtils.isEmpty(password)) {
            etPassword.setError("Please enter your password");
            etPassword.requestFocus();
            return;
        }

        //if everything is fine
        StringRequest stringRequest = new StringRequest(Request.Method.POST, URLs.URL_LOGIN,
                new Response.Listener() {
                    @Override
                    public void onResponse(String response) {
                        progressBar.setVisibility(View.GONE);

                        try {
                            //converting response to json object
                            JSONObject obj = new JSONObject(response);

                            //if no error in response
                            if (!obj.getBoolean("error")) {
                                Toast.makeText(getApplicationContext(), obj.getString("message"), Toast.LENGTH_SHORT).show();

                                //getting the user from the response
                                JSONObject userJson = obj.getJSONObject("user");

                                //creating a new user object
                                User user = new User(
                                        userJson.getInt("id"),
                                        userJson.getString("username"),
                                        userJson.getString("email"),
                                        userJson.getString("gender")
                                );

                                //storing the user in shared preferences
                                SharedPrefManager.getInstance(getApplicationContext()).userLogin(user);
                                //starting the profile activity
                                finish();
                                startActivity(new Intent(getApplicationContext(), MainActivity.class));
                            } else {
                                Toast.makeText(getApplicationContext(), obj.getString("message"), Toast.LENGTH_SHORT).show();
                            }
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_SHORT).show();

                    }
                })
        {
            @Override
            protected Map getParams() throws AuthFailureError {
                Map params = new HashMap<>();
                params.put("username", username);
                params.put("password", password);
                return params;
            }
        };

        VolleySingleton.getInstance(this).addToRequestQueue(stringRequest);
    }
}

RegisterActivity.java类用于注册用户。此类最初检查用户登录是否正确，然后重定向到MainActivity.java类，否则，允许用户注册。

与LoginActivity.java类类似，我们使用Volley库的StringRequest类进行网络连接，并传递类型请求方法，URL和响应的参数。 Response.Listener ()方法处理服务器生成的响应。

RegisterActivity.java

package example.javatpoint.com.volleyregistrationloginsystem;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.RadioButton;
import android.widget.RadioGroup;
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 org.json.JSONException;
import org.json.JSONObject;
import java.util.HashMap;
import java.util.Map;

public class RegisterActivity extends AppCompatActivity {
    EditText editTextUsername, editTextEmail, editTextPassword;
    RadioGroup radioGroupGender;
    ProgressBar progressBar;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);
        progressBar = findViewById(R.id.progressBar);

        //if the user is already logged in we will directly start the MainActivity (profile) activity
        if (SharedPrefManager.getInstance(this).isLoggedIn()) {
            finish();
            startActivity(new Intent(this, MainActivity.class));
            return;
        }

        editTextUsername = findViewById(R.id.editTextUsername);
        editTextEmail = findViewById(R.id.editTextEmail);
        editTextPassword = findViewById(R.id.editTextPassword);
        radioGroupGender = findViewById(R.id.radioGender);


        findViewById(R.id.buttonRegister).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //if user pressed on button register
                //here we will register the user to server
                registerUser();
            }
        });

        findViewById(R.id.textViewLogin).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //if user pressed on textview that already register open LoginActivity
                finish();
                startActivity(new Intent(RegisterActivity.this, LoginActivity.class));
            }
        });

    }

    private void registerUser() {
        final String username = editTextUsername.getText().toString().trim();
        final String email = editTextEmail.getText().toString().trim();
        final String password = editTextPassword.getText().toString().trim();

        final String gender = ((RadioButton) findViewById(radioGroupGender.getCheckedRadioButtonId())).getText().toString();

        //first we will do the validations
        if (TextUtils.isEmpty(username)) {
            editTextUsername.setError("Please enter username");
            editTextUsername.requestFocus();
            return;
        }

        if (TextUtils.isEmpty(email)) {
            editTextEmail.setError("Please enter your email");
            editTextEmail.requestFocus();
            return;
        }

        if (!android.util.Patterns.EMAIL_ADDRESS.matcher(email).matches()) {
            editTextEmail.setError("Enter a valid email");
            editTextEmail.requestFocus();
            return;
        }

        if (TextUtils.isEmpty(password)) {
            editTextPassword.setError("Enter a password");
            editTextPassword.requestFocus();
            return;
        }

        StringRequest stringRequest = new StringRequest(Request.Method.POST, URLs.URL_REGISTER,
                new Response.Listener() {
                    @Override
                    public void onResponse(String response) {
                        progressBar.setVisibility(View.GONE);

                        try {
                            //converting response to json object
                            JSONObject obj = new JSONObject(response);
                            //if no error in response
                            if (!obj.getBoolean("error")) {
                                Toast.makeText(getApplicationContext(), obj.getString("message"), Toast.LENGTH_SHORT).show();

                                //getting the user from the response
                                JSONObject userJson = obj.getJSONObject("user");

                                //creating a new user object
                                User user = new User(
                                        userJson.getInt("id"),
                                        userJson.getString("username"),
                                        userJson.getString("email"),
                                        userJson.getString("gender")
                                );

                                //storing the user in shared preferences
                                SharedPrefManager.getInstance(getApplicationContext()).userLogin(user);

                                //starting the profile activity
                                finish();
                                startActivity(new Intent(getApplicationContext(), MainActivity.class));
                            } else {
                                Toast.makeText(getApplicationContext(), obj.getString("message"), Toast.LENGTH_SHORT).show();
                            }
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_SHORT).show();
                    }
                }) {
            @Override
            protected Map getParams() throws AuthFailureError {
                Map params = new HashMap<>();
                params.put("username", username);
                params.put("email", email);
                params.put("password", password);
                params.put("gender", gender);
                return params;
            }
        };

        VolleySingleton.getInstance(this).addToRequestQueue(stringRequest);
    }
}

在AndroidManifest.xml文件中添加以下权限

AndroidManifest.xml

输出：