add camera permission check

Author: thatfiredev

firebase-ai/app/src/main/java/com/google/firebase/quickstart/ai/ui/HybridInferenceScreen.kt

@@ -1,7 +1,10 @@
 package com.google.firebase.quickstart.ai.ui
 
+import android.Manifest
+import android.content.pm.PackageManager
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
+import androidx.core.content.ContextCompat
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -54,11 +57,25 @@ fun HybridInferenceScreen(
         }
     )
 
+    val permissionLauncher = rememberLauncherForActivityResult(
+        ActivityResultContracts.RequestPermission()
+    ) { isGranted ->
+        if (isGranted) {
+            cameraLauncher.launch(null)
+        }
+    }
+
     Scaffold(
         floatingActionButton = {
             FloatingActionButton(
                 onClick = {
-                    cameraLauncher.launch(null)
+                    val permissionCheckResult =
+                        ContextCompat.checkSelfPermission(context, Manifest.permission.CAMERA)
+                    if (permissionCheckResult == PackageManager.PERMISSION_GRANTED) {
+                        cameraLauncher.launch(null)
+                    } else {
+                        permissionLauncher.launch(Manifest.permission.CAMERA)
+                    }
                 },
                 containerColor = MaterialTheme.colorScheme.primary,
                 contentColor = MaterialTheme.colorScheme.onPrimary