Kotlin Android Web Service - 使用 Volley 库的注册、登录和注销教程

2025年3月17日 | 阅读 8 分钟

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网络连接功能。

注册和登录的 Web API 是使用 PHP 和 MySQL 创建的。在实现客户端 Android 应用程序代码之前，首先查看服务器端 API 代码，网址为 https://tpointtech.cn/android-volley-library-registration-login-logout。

在 Android 应用程序中，我们将创建三个活动类，用于用户注册、用户登录并在主活动中显示用户详细信息（作为个人资料）。

在布局中创建一个 activity_main.xml 并添加以下代码。此活动用于显示用户个人资料的详细信息。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="example.javatpoint.com.kotlinvolleyregistrationloginsystem.MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="fill_parent"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:orientation="vertical"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0">

        <TextView
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:text="Welcome to Profile"
            android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />

        <TableLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="50dp">


            <TableRow>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:padding="10dp"
                    android:text="Id"
                    android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />

                <TextView
                    android:id="@+id/textViewId"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:padding="10dp"
                    android:text="id"
                    android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />

            </TableRow>

            <TableRow>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:padding="10dp"
                    android:text="Username"
                    android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />

                <TextView
                    android:id="@+id/textViewUsername"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:padding="10dp"
                    android:text="username"
                    android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />

            </TableRow>

            <TableRow>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:padding="10dp"
                    android:text="Email"
                    android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />

                <TextView
                    android:id="@+id/textViewEmail"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:padding="10dp"
                    android:text="useremail"
                    android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />

            </TableRow>

            <TableRow>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:padding="10dp"
                    android:text="Gender"
                    android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />

                <TextView
                    android:id="@+id/textViewGender"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:padding="10dp"
                    android:text="gender"
                    android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />

            </TableRow>


        </TableLayout>

        <Button
            android:id="@+id/buttonLogout"
            android:layout_width="210dp"
            android:layout_height="50dp"
            android:layout_marginTop="150dp"
            android:layout_marginLeft="75dp"
            android:text="Logout" />
    </LinearLayout>

</android.support.constraint.ConstraintLayout>

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

activity_login.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="example.javatpoint.com.kotlinvolleyregistrationloginsystem.LoginActivity">

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="16dp"
        android:gravity="center"
        android:text="Login"
        android:textAppearance="@style/Base.TextAppearance.AppCompat.Large"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/etUserName"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:ems="10"
        android:inputType="textPersonName"
        android:hint="user name"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.144" />

    <EditText
        android:id="@+id/etUserPassword"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:hint="password"
        android:ems="10"
        android:inputType="textPassword"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/etUserName" />

    <Button
        android:id="@+id/btnLogin"
        android:layout_width="210dp"
        android:layout_height="50dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="Login"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/etUserName"
        app:layout_constraintVertical_bias="0.754" />

    <TextView
        android:id="@+id/tvRegister"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:gravity="center"
        android:text="Create New Account\n Register Here"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btnLogin"
        app:layout_constraintVertical_bias="0.405" />

    <ProgressBar
        android:id="@+id/progressBar"
        android:visibility="gone"
        style="?android:attr/progressBarStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.456" />

</android.support.constraint.ConstraintLayout>

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

activity_register.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="example.javatpoint.com.kotlinvolleyregistrationloginsystem.RegisterActivity">


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="519dp"
        android:layout_centerVertical="true"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:orientation="vertical"
        android:padding="10dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0">

        <TextView
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Register"
            android:gravity="center"
            android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />

        <EditText
            android:id="@+id/editTextUsername"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="8dp"
            android:layout_marginTop="20dp"
            android:hint="Username"
            android:inputType="text" />

        <EditText
            android:id="@+id/editTextEmail"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="8dp"
            android:layout_marginTop="8dp"
            android:hint="Email"
            android:inputType="textEmailAddress" />

        <EditText
            android:id="@+id/editTextPassword"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="8dp"
            android:layout_marginTop="8dp"
            android:fontFamily="sans-serif"
            android:hint="Password"
            android:inputType="textPassword" />

        <RadioGroup
            android:id="@+id/radioGender"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="8dp"
            android:layout_marginTop="8dp"
            android:orientation="horizontal">

            <RadioButton
                android:id="@+id/radioButtonMale"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:checked="true"
                android:text="Male" />


            <RadioButton
                android:id="@+id/radioButtonFemale"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Female" />

        </RadioGroup>

        <Button
            android:id="@+id/buttonRegister"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="8dp"
            android:layout_marginTop="90dp"
            android:text="Register" />

        <TextView
            android:id="@+id/textViewLogin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="8dp"
            android:layout_marginTop="8dp"
            android:text="Already Registered?\nLogin Here"
            android:textAlignment="center"
            android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
    </LinearLayout>

    <ProgressBar
        android:visibility="gone"
        android:id="@+id/progressBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true" />

</android.support.constraint.ConstraintLayout>

在 build.gradle 文件中添加 volley 库依赖项。

build.gradle

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    implementation 'com.android.volley:volley:1.0.0'
}

创建一个名为 User.kt 的数据模型类，其中包含以下代码。

User.kt

package example.javatpoint.com.kotlinvolleyregistrationloginsystem

class User(var id: Int, var name: String?, var email: String?, var gender: String?)

我们需要定义调用服务器端 API 的 URL。

创建一个 URLs.kt 类并定义 URL。

URLs.kt

package example.javatpoint.com.kotlinvolleyregistrationloginsystem

object URLs {
    private val ROOT_URL = "http://192.168.1.35/androidphpmysql/registrationapi.php?apicall="
    val URL_REGISTER = ROOT_URL + "signup"
    val URL_LOGIN = ROOT_URL + "login"
}

VolleySingleton.kt

package example.javatpoint.com.kotlinvolleyregistrationloginsystem

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

class VolleySingleton private constructor(context: Context) {
    private var mRequestQueue: RequestQueue

    // applicationContext is key, it keeps you from leaking the
    // Activity or BroadcastReceiver if someone passes one in.
    val requestQueue: RequestQueue
        get() {
            if (mRequestQueue == null) {
                mRequestQueue = Volley.newRequestQueue(mCtx?.applicationContext)
            }
            return mRequestQueue
        }

    init {
        mCtx = context
        mRequestQueue = requestQueue
    }

    fun <T> addToRequestQueue(req: Request<T>) {
        requestQueue.add(req)
    }

    companion object {
        private var mInstance: VolleySingleton? = null
        private var mCtx: Context? = null

        @Synchronized
        fun getInstance(context: Context): VolleySingleton {
            if (mInstance == null) {
                mInstance = VolleySingleton(context)
            }
            return mInstance as VolleySingleton
        }
    }
}

创建一个名为 SharedPreferences.kt 的类。在此类中，我们使用 SharedPreferences 类来存储用户详细信息。 SharedPreferences 类包含四个方法，具有以下功能

userLogin(): 此函数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登录。
user: User get(): 如果已登录，此方法会获取用户信息。
logout(): 此函数清除 SharedPreferences 数据并使用户注销。

SharedPrefManager.kt

package example.javatpoint.com.kotlinvolleyregistrationloginsystem

import android.content.Context
import android.content.Intent

class SharedPrefManager private constructor(context: Context) {

    //this method will checker whether user is already logged in or not
    val isLoggedIn: Boolean
        get() {
            val sharedPreferences = ctx?.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE)
            return sharedPreferences?.getString(KEY_USERNAME, null) != null
        }

    //this method will give the logged in user
    val user: User
        get() {
            val sharedPreferences = ctx?.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE)
            return User(
                    sharedPreferences!!.getInt(KEY_ID, -1),
                    sharedPreferences.getString(KEY_USERNAME, null),
                    sharedPreferences.getString(KEY_EMAIL, null),
                    sharedPreferences.getString(KEY_GENDER, null)
            )
        }

    init {
        ctx = context
    }

    //this method will store the user data in shared preferences
    fun userLogin(user: User) {
        val sharedPreferences = ctx?.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE)
        val editor = sharedPreferences?.edit()
        editor?.putInt(KEY_ID, user.id)
        editor?.putString(KEY_USERNAME, user.name)
        editor?.putString(KEY_EMAIL, user.email)
        editor?.putString(KEY_GENDER, user.gender)
        editor?.apply()
    }

    //this method will logout the user
    fun logout() {
        val sharedPreferences = ctx?.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE)
        val editor = sharedPreferences?.edit()
        editor?.clear()
        editor?.apply()
        ctx?.startActivity(Intent(ctx, LoginActivity::class.java))
    }

    companion object {

        private val SHARED_PREF_NAME = "volleyregisterlogin"
        private val KEY_USERNAME = "keyusername"
        private val KEY_EMAIL = "keyemail"
        private val KEY_GENDER = "keygender"
        private val KEY_ID = "keyid"
        private var mInstance: SharedPrefManager? = null
        private var ctx: Context? = null
        @Synchronized
        fun getInstance(context: Context): SharedPrefManager {
            if (mInstance == null) {
                mInstance = SharedPrefManager(context)
            }
            return mInstance as SharedPrefManager
        }
    }
}

现在，在 MainActivity.kt 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.kt 类。当单击按钮时，onClick() 方法用于注销用户。

MainActivity.kt

package example.javatpoint.com.kotlinvolleyregistrationloginsystem

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

class MainActivity : AppCompatActivity(), View.OnClickListener {

    internal lateinit var id: TextView
    internal lateinit var userName: TextView
    internal lateinit var userEmail: TextView
    internal lateinit var gender: TextView
    internal lateinit var btnLogout: Button
    override fun onCreate(savedInstanceState: Bundle?) {
        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)

            val user = SharedPrefManager.getInstance(this).user

            id.text = user.id.toString()
            userEmail.text = user.email
            gender.text = user.gender
            userName.text = user.name

            btnLogout.setOnClickListener(this)

        } else {
            val intent = Intent(this@MainActivity, LoginActivity::class.java)
            startActivity(intent)
            finish()
        }
    }

    override fun onClick(view: View) {
        if (view == btnLogout) {
            SharedPrefManager.getInstance(applicationContext).logout()
        }
    }
}

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

Volley 库的 StringRequest 类用于网络模块。 StringRequest 类的对象采用请求方法、URL 和响应类型的参数。

LoginActivity.kt

package example.javatpoint.com.kotlinvolleyregistrationloginsystem

import android.support.v7.app.AppCompatActivity
import android.os.Bundle

import android.content.Intent
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.toolbox.StringRequest
import kotlinx.android.synthetic.main.activity_login.*
import org.json.JSONException
import org.json.JSONObject
import java.util.HashMap

class LoginActivity : AppCompatActivity() {
    internal lateinit var etName: EditText
    internal lateinit var etPassword: EditText
    internal lateinit var progressBar: ProgressBar
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_login)

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

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

        //calling the method userLogin() for login the user
         btnLogin.setOnClickListener(View.OnClickListener {
            userLogin()
        })

        //if user presses on textview it call the activity RegisterActivity
        tvRegister.setOnClickListener(View.OnClickListener {
            finish()
            startActivity(Intent(applicationContext, RegisterActivity::class.java))
        })
    }

    private fun userLogin() {
        //first getting the values
        val username = etName.text.toString()
        val password = etPassword.text.toString()
        //validating inputs
        if (TextUtils.isEmpty(username)) {
            etName.error = "Please enter your username"
            etName.requestFocus()
            return
        }

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

        //if everything is fine
        val stringRequest = object : StringRequest(Request.Method.POST, URLs.URL_LOGIN,
                Response.Listener { response ->
                    progressBar.visibility = View.GONE

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

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

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

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

                            //storing the user in shared preferences
                            SharedPrefManager.getInstance(applicationContext).userLogin(user)
                            //starting the MainActivity
                            finish()
                            startActivity(Intent(applicationContext, MainActivity::class.java))
                        } else {
                            Toast.makeText(applicationContext, obj.getString("message"), Toast.LENGTH_SHORT).show()
                        }
                    } catch (e: JSONException) {
                        e.printStackTrace()
                    }
                },
                Response.ErrorListener { error -> Toast.makeText(applicationContext, error.message, Toast.LENGTH_SHORT).show() }) {
            @Throws(AuthFailureError::class)
            override fun getParams(): Map<String, String> {
                val params = HashMap<String, String>()
                params["username"] = username
                params["password"] = password
                return params
            }
        }

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

RegisterActivity.kt 类用于注册用户。此类最初检查用户登录，如果为 true，则重定向到 MainActivity.kt 类，否则，允许用户注册。

与 LoginActivity.kt 类类似，我们使用 Volley 库的 StringRequest 类进行网络连接，并传递请求方法、URL 和响应类型的参数。 Response.Listener 处理服务器生成的响应。

RegisterActivity.kt

package example.javatpoint.com.kotlinvolleyregistrationloginsystem

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.content.Intent
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.toolbox.StringRequest
import kotlinx.android.synthetic.main.activity_register.*
import org.json.JSONException
import org.json.JSONObject
import java.util.HashMap

class RegisterActivity : AppCompatActivity() {
    internal lateinit var editTextUsername: EditText
    internal lateinit var editTextEmail: EditText
    internal lateinit var editTextPassword: EditText
    internal lateinit var radioGroupGender: RadioGroup
    internal lateinit var progressBar: ProgressBar
    override fun onCreate(savedInstanceState: Bundle?) {
        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(Intent(this, MainActivity::class.java))
            return
        }

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

        buttonRegister.setOnClickListener(View.OnClickListener {
            //if user pressed on button register
            //here we will register the user to server
            registerUser()
        })

        textViewLogin.setOnClickListener(View.OnClickListener {
            finish()
            startActivity(Intent(this@RegisterActivity, LoginActivity::class.java))
        })
    }

    private fun registerUser() {
        val username = editTextUsername.text.toString().trim { it <= ' ' }
        val email = editTextEmail.text.toString().trim { it <= ' ' }
        val password = editTextPassword.text.toString().trim { it <= ' ' }

        val gender = (findViewById<View>(radioGroupGender.checkedRadioButtonId) as RadioButton).text.toString()

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

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

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

        if (TextUtils.isEmpty(password)) {
            editTextPassword.error = "Enter a password"
            editTextPassword.requestFocus()
            return
        }

        val stringRequest = object : StringRequest(Request.Method.POST, URLs.URL_REGISTER,
                Response.Listener { response ->
                    progressBar.visibility = View.GONE

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

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

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

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

                            //starting the MainActivity activity
                            finish()
                            startActivity(Intent(applicationContext, MainActivity::class.java))
                        } else {
                            Toast.makeText(applicationContext, obj.getString("message"), Toast.LENGTH_SHORT).show()
                        }
                    } catch (e: JSONException) {
                        e.printStackTrace()
                    }
                },
                Response.ErrorListener { error -> Toast.makeText(applicationContext, error.message, Toast.LENGTH_SHORT).show() }) {
            @Throws(AuthFailureError::class)
            override fun getParams(): Map<String, String> {
                val params = HashMap<String, String>()
                params["username"] = username
                params["email"] = email
                params["password"] = password
                params["gender"] = gender
                return params
            }
        }

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

AndroidManifest.xml

在 AndroidManifest.xml 文件中添加以下权限

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />

注意：注册和登录的服务器端代码是在 PHP 中使用 MySQL 实现的，网址为 https://tpointtech.cn/android-volley-library-registration-login-logout。

输出

下一主题#

Kotlin Android Web Service - 使用 Volley 库的注册、登录和注销教程

activity_main.xml

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

activity_login.xml

activity_register.xml

build.gradle

User.kt

URLs.kt

VolleySingleton.kt

SharedPrefManager.kt

MainActivity.kt

LoginActivity.kt

RegisterActivity.kt

AndroidManifest.xml

注意：注册和登录的服务器端代码是在 PHP 中使用 MySQL 实现的，网址为 https://tpointtech.cn/android-volley-library-registration-login-logout。

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Kotlin Android Web Service - 使用 Volley 库的注册、登录和注销教程

activity_main.xml

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

activity_login.xml

activity_register.xml

build.gradle

User.kt

URLs.kt

VolleySingleton.kt

SharedPrefManager.kt

MainActivity.kt

LoginActivity.kt

RegisterActivity.kt

AndroidManifest.xml

注意：注册和登录的服务器端代码是在 PHP 中使用 MySQL 实现的，网址为 https://tpointtech.cn/android-volley-library-registration-login-logout。

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面试题

在线编译器

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