add basic auth (PIN)

app/src/main/java/com/bintianqi/owndroid/Auth.kt

@@ -0,0 +1,92 @@
+package com.bintianqi.owndroid
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.content.Intent
+import android.os.Bundle
+import android.widget.Toast
+import androidx.activity.compose.setContent
+import androidx.activity.enableEdgeToEdge
+import androidx.biometric.BiometricManager
+import androidx.biometric.BiometricPrompt
+import androidx.biometric.BiometricPrompt.AuthenticationCallback
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.material3.Button
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.core.content.ContextCompat
+import androidx.core.view.WindowCompat
+import androidx.fragment.app.FragmentActivity
+import com.bintianqi.owndroid.ui.theme.OwnDroidTheme
+
+var authenticated = false
+
+class AuthActivity: FragmentActivity(){
+    @SuppressLint("UnrememberedMutableState")
+    @OptIn(ExperimentalMaterial3Api::class)
+    override fun onCreate(savedInstanceState: Bundle?) {
+        enableEdgeToEdge()
+        WindowCompat.setDecorFitsSystemWindows(window, false)
+        super.onCreate(savedInstanceState)
+        val mainActivityIntent = Intent(applicationContext, MainActivity::class.java)
+        val sharedPref = applicationContext.getSharedPreferences("data", Context.MODE_PRIVATE)
+        val callback = object: AuthenticationCallback() {
+            override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
+                super.onAuthenticationSucceeded(result)
+                authenticated = true
+                startActivity(mainActivityIntent)
+                finish()
+            }
+            override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
+                super.onAuthenticationError(errorCode, errString)
+                Toast.makeText(applicationContext, errString, Toast.LENGTH_SHORT).show()
+                /*if (errString.toString().isNotEmpty()) {
+                }*/
+            }
+        }
+        setContent {
+            val materialYou = mutableStateOf(sharedPref.getBoolean("material_you",true))
+            val blackTheme = mutableStateOf(sharedPref.getBoolean("black_theme", false))
+            OwnDroidTheme(materialYou.value, blackTheme.value) {
+                Auth(this, callback)
+            }
+        }
+    }
+}
+
+@Composable
+fun Auth(activity: FragmentActivity, callback: AuthenticationCallback) {
+    Column(
+        horizontalAlignment = Alignment.CenterHorizontally,
+        verticalArrangement = Arrangement.Center,
+        modifier = Modifier.fillMaxSize()
+    ){
+        Text(text = "Authenticate", style = MaterialTheme.typography.headlineLarge)
+        Button(
+            onClick = {
+                authWithBiometricPrompt(activity, callback)
+            }
+        ){
+            Text(text = "Start")
+        }
+    }
+}
+
+private fun authWithBiometricPrompt(activity: FragmentActivity, callback: AuthenticationCallback) {
+    val executor = ContextCompat.getMainExecutor(activity.applicationContext)
+    val biometricPrompt = BiometricPrompt(activity, executor, callback)
+    val promptInfo = BiometricPrompt.PromptInfo.Builder()
+        .setAllowedAuthenticators(BiometricManager.Authenticators.DEVICE_CREDENTIAL)
+        .setTitle("Auth")
+        .setConfirmationRequired(true)
+        .setSubtitle("Enter password")
+        .build()
+    biometricPrompt.authenticate(promptInfo)
+}