通过API从SQL数据库读写数据并显示数据

Question

祝大家一切顺利。

我遇到了一些问题，似乎在网上找不到适用于我的情况的答案。我在Kotlin编码。

我的数据库位于外部主机上，但我已经建立并连接了数据库连接。

1. 我有一个登录活动与用户名和密码字段，和一个登录按钮。我已经设法通过设置特定的凭据来验证登录细节，但我现在有一个数据库，SQL，链接到我的android app。如何根据数据库验证用户输入的登录凭据，并检查用户是否处于活动状态?

Name: BobbyDatabase Host: sql99.dbn7.host-h.netDatabase Name: JimmysWorldDBDriver Source: Built-in library

这里使用的表如下:

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. 所以基本上我想知道如何使app检查验证UsernameandPassword且仅当成员HasAccess = true然后成功登录。<——全部来自UserLogins表

如果用户已经成功登录，保存一个LoginRecord，它把date,login time和username。

我的代码如下:

LoginActivity.kt按钮名称为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")
}
}

我很抱歉这么长，感谢任何帮助我可以得到。提前谢谢。

Answer 1

您可能需要一个数据库驱动程序。

我没有为Android写过，但看起来Android不支持mysql数据库连接。实现这一点的一种方法是使用PHP中间商。这是野生的。

这里有一个关于使用PHP实现此目的的链接。https://www.tutorialspoint.com/android/android_php_mysql.htm