I hope you are all doing well.

I have run into a few problems and can't seem to find the answer online in an applicable way to my scenario. I am coding in Kotlin.

My database resides on an external host but I have already got the database connection set up and connected.

1. I have a login activity with a username and password field, and a login button. I have managed to verify the login details by setting specific credentials but I now have a database, SQL, linked to my android app. How do I verify the login credentials the user input against the database and check if the user is active?

Name: Bobby Database Host: sql99.dbn7.host-h.net Database Name: JimmysWorldDB Driver Source: Built-in library

The tables used here are as follows:

1. UserLogins
    Column 1 : UserID
    Column 2 : FullName
    Column 3 : Username
    Column 4 : Password
    Column 5 : HasAccess

2. LoginRecords
    Column 1 : RecordID
    Column 2 : Date
    Column 3 : Logon     <--- This is a time field
    Column 4 : Logoff    <--- This is a time field
    Column 5 : Username

2. So basically I would like to know how to make the app check the verify the Username and Password and only if the member HasAccess = true then have a successful login. <--- All from UserLogins table

Then if the user has logged in successfully, save a LoginRecord where it puts the date, login time and the username.

My code is as follows below.

LoginActivity.kt name of the button is button_login

import android.app.Activity
import android.content.Intent
import android.os.Bundle
import android.text.Editable
import android.text.TextWatcher
import android.view.View
import android.view.inputmethod.EditorInfo
import android.widget.EditText
import android.widget.Toast
import androidx.annotation.StringRes
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProvider
import com.jimmysworld.MainActivity
import com.jimmysworld.R
import com.jimmysworld.databinding.ActivityLoginBinding

class LoginActivity : AppCompatActivity() {

    private lateinit var loginViewModel: LoginViewModel
    private lateinit var binding: ActivityLoginBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        binding = ActivityLoginBinding.inflate(layoutInflater)
        setContentView(binding.root)

        val username = binding.username
        val password = binding.password
        val login = binding.login
        val loading = binding.loading

        loginViewModel = ViewModelProvider(this, LoginViewModelFactory())[LoginViewModel::class.java]

        loginViewModel.loginFormState.observe(this@LoginActivity, Observer {
            val loginState = it ?: return@Observer

            // disable login button unless both username / password is valid
            login.isEnabled = loginState.isDataValid

            if (loginState.usernameError != null) {
                username.error = getString(loginState.usernameError)
            }
            if (loginState.passwordError != null) {
                password.error = getString(loginState.passwordError)
            }
        })

        loginViewModel.loginResult.observe(this@LoginActivity, Observer {
            val loginResult = it ?: return@Observer

            loading.visibility = View.GONE
            if (loginResult.error != null) {
                showLoginFailed(loginResult.error)
            }
            if (loginResult.success != null) {
                updateUiWithUser(loginResult.success)
            }
            setResult(Activity.RESULT_OK)

            //Complete and destroy login activity once successful
            finish()
        })

        username.afterTextChanged {
            loginViewModel.loginDataChanged(
                username.text.toString(),
                password.text.toString()
            )
        }

        password.apply {
            afterTextChanged {
                loginViewModel.loginDataChanged(
                    username.text.toString(),
                    password.text.toString()
                )
            }

            setOnEditorActionListener { _, actionId, _ ->
                when (actionId) {
                    EditorInfo.IME_ACTION_DONE ->
                        loginViewModel.login(
                            username.text.toString(),
                            password.text.toString()
                        )
                }
                false
            }

            login.setOnClickListener {
                loading.visibility = View.VISIBLE
                loginViewModel.login(username.text.toString(), password.text.toString())
            }
        }
    }

    private fun updateUiWithUser(model: LoggedInUserView) {
        val welcome = getString(R.string.welcome)
        val displayName = model.displayName
        // TODO : initiate successful logged in experience
        Toast.makeText(
            applicationContext,
            "$welcome $displayName",
            Toast.LENGTH_LONG
        ).show()
        val intent = Intent(this, MainActivity::class.java)
        startActivity(intent)
    }

    private fun showLoginFailed(@StringRes errorString: Int) {
        Toast.makeText(applicationContext, errorString, Toast.LENGTH_SHORT).show()
    }
}

LoginViewModel.kt

import android.util.Patterns
import androidx.lifecycle.LiveData
import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.ViewModel
import com.jimmysworld.R
import com.jimmysworld.data.LoginRepository
import com.jimmysworld.data.Result


class LoginViewModel(private val loginRepository: LoginRepository) : ViewModel() {

    private val _loginForm = MutableLiveData<LoginFormState>()
    val loginFormState: LiveData<LoginFormState> = _loginForm

    private val _loginResult = MutableLiveData<LoginResult>()
    val loginResult: LiveData<LoginResult> = _loginResult

    fun login(username: String, password: String) {
        // can be launched in a separate asynchronous job
        val result = loginRepository.login(username, password)
        val user = "Admin"
        val pass = "1234567"


        if (username.toString() == user && password.toString() == pass) {
            if (result is Result.Success) {
                _loginResult.value =
                    LoginResult(success = LoggedInUserView(displayName = result.data.displayName))
            }
        } else {
            _loginResult.value = LoginResult(error = R.string.login_failed)
        }
    }

    fun loginDataChanged(username: String, password: String) {
        if (!isUserNameValid(username)) {
            _loginForm.value = LoginFormState(usernameError = R.string.invalid_username)
        } else if (!isPasswordValid(password)) {
            _loginForm.value = LoginFormState(passwordError = R.string.invalid_password)
        } else {
            _loginForm.value = LoginFormState(isDataValid = true)
        }
    }

    // A placeholder username validation check
    private fun isUserNameValid(username: String): Boolean {
        return if (username.contains('@')) {
            Patterns.EMAIL_ADDRESS.matcher(username).matches()
        } else {
            username.isNotBlank()
        }
    }

    // A placeholder password validation check
    private fun isPasswordValid(password: String): Boolean {
        return password.length > 7
    }
}

LoggedInUser

import com.jimmysworld.data.model.LoggedInUser

class LoginRepository(val dataSource: LoginDataSource) {

    var user: LoggedInUser? = null
        private set

    val isLoggedIn: Boolean
        get() = user != null

    init {
        user = null
    }

    fun logout() {
        user = null
        dataSource.logout()
    }

    fun login(username: String, password: String): Result<LoggedInUser> {
        // handle login
        val result = dataSource.login(username, password)

        if (result is Result.Success) {
            setLoggedInUser(result.data)
        }

        return result
    }

    private fun setLoggedInUser(loggedInUser: LoggedInUser) {
        this.user = loggedInUser
    }
}

LoginViewModelFactory.kt

import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import com.jimmysworld.data.LoginDataSource
import com.jimmysworld.data.LoginRepository


class LoginViewModelFactory : ViewModelProvider.Factory {

    @Suppress("UNCHECKED_CAST")
    override fun <T : ViewModel> create(modelClass: Class<T>): T {
        if (modelClass.isAssignableFrom(LoginViewModel::class.java)) {
            return LoginViewModel(
                loginRepository = LoginRepository(
                    dataSource = LoginDataSource()
                )
            ) as T
        }
        throw IllegalArgumentException("Unknown ViewModel class")
    }
}

I am sorry for it being so long winded and appreciate any help I can get. Thanks in advance.

CodePudding user response：

You probably need a database driver.

I have not written for Android, but it looks like Android does not natively support mysql db connections. One way to make this happen is to use a PHP middleman. That's wild.

Here is a link about using PHP for this purpose. https://www.tutorialspoint.com/android/android_php_mysql.htm