Build an Android Application with Authentication

git clone https://github.com/oktadeveloper/okta-oidc-android-example.git
cd okta-oidc-android-example

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:orientation="vertical">

    <Button
        android:id="@+id/signIn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Sign in" />

    </LinearLayout>

</ScrollView>

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

import kotlinx.android.synthetic.main.main_activity.*

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    setupWebAuth()
    setupWebAuthCallback(webAuth)

    signIn.setOnClickListener {
        val payload = AuthenticationPayload.Builder()
            .build()
        webAuth.signIn(this, payload)
    }
}

if (sessionClient.isAuthenticated) {
    // Do something specific to authenticated users
} else {
    // Do something to non-authenticated users
}

private fun downloadProfile() {
    sessionClient.getUserProfile(object : RequestCallback<UserInfo, AuthorizationException> {
        override fun onSuccess(result: UserInfo) {
            Log.d("Profile", result.toString())
        }

        override fun onError(error: String?, exception: AuthorizationException?) {
            Log.d("Profile", error, exception.cause)
        }
    })
}

signIn.setOnClickListener {
    val payload = AuthenticationPayload.Builder()
        .setIdp("{IdP-id}") // From your "Okta" admin console
        .setIdpScope("clientScope1", "clientScope2", "clientScope3") // Optional, in case the IDP requires it
        .build()
    webAuth.signIn(this, payload)
}

import androidx.biometric.BiometricConstants.ERROR_NEGATIVE_BUTTON
import androidx.biometric.BiometricPrompt
import androidx.biometric.BiometricPrompt.PromptInfo
import androidx.fragment.app.FragmentActivity
import java.util.concurrent.Executors

class Biometric(
    fragmentActivity: FragmentActivity,
    onSuccessListener: () -> Unit,
    onCancelListener: () -> Unit,
    onErrorListener: (Int, String) -> Unit) {

    private val mCallback: BiometricPrompt.AuthenticationCallback =
        object : BiometricPrompt.AuthenticationCallback() {
            override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
                if (errorCode == ERROR_NEGATIVE_BUTTON) {
                    onCancelListener()
                } else {
                    onErrorListener(errorCode, errString.toString())
                }
                prompt.cancelAuthentication()
            }

            override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
                onSuccessListener()
            }
         }

    private val prompt: BiometricPrompt
    private val promptInfo: PromptInfo

    init {
        prompt = BiometricPrompt(fragmentActivity, Executors.newSingleThreadExecutor(), mCallback)
        promptInfo = PromptInfo.Builder()
            .setTitle("Biometric authentication succeeded")
            .setDeviceCredentialAllowed(true)
            .setConfirmationRequired(true)
            .build()
    }

    fun show() {
        prompt.authenticate(promptInfo)
    }
}

import com.okta.oidc.storage.security.DefaultEncryptionManager
import com.okta.oidc.storage.security.EncryptionManager
import com.okta.oidc.storage.security.GuardedEncryptionManager

private var currentEncryptionManager: EncryptionManager? = null
private var keyguardEncryptionManager: GuardedEncryptionManager? = null

override fun onResume() {
    super.onResume()

    // Check whether the user has already authenticated using the device's authentication method. If it hasn't, ask them to do it
    if (currentEncryptionManager?.isUserAuthenticatedOnDevice?.not() == true) {
        showKeyguard()
    }
}

private fun showKeyguard() {
    Biometric(
        fragmentActivity = this,
        onSuccessListener = {
            Log.d("MainActivity", "Biometric authentication succeeded")
            Toast.makeText(this, "Biometric authentication succeeded", Toast.LENGTH_SHORT).show()
        },
        onCancelListener = {
            runOnUiThread {
                Log.d("MainActivity", "Biometric authentication cancelled")
                Toast.makeText(this, "Biometric authentication cancelled", Toast.LENGTH_SHORT).show()
                finish()
            }
        },
        onErrorListener = { code, message ->
            runOnUiThread {
                Log.d("MainActivity", "Biometric authentication failed")
                Toast.makeText(this, "Biometric authentication failed", Toast.LENGTH_SHORT).show()
                finish()
            }
        }).show()
}

private fun setupWebAuth() {
    keyguardEncryptionManager = GuardedEncryptionManager(this, Int.MAX_VALUE)

    webAuth = WebAuthBuilder()
        .withConfig(oidcConfig)
        .withContext(applicationContext)
        .withCallbackExecutor(null)
        .withEncryptionManager(keyguardEncryptionManager)
        .create()
    sessionClient = webAuth.sessionClient
}