add kotlin snippets

Author: kroikie

messaging/app/src/main/java/com/google/firebase/example/messaging/kotlin/MainActivity.kt

@@ -1,9 +1,14 @@
 package com.google.firebase.example.messaging.kotlin
 
+import android.Manifest
+import android.content.pm.PackageManager
 import android.os.Bundle
 import android.util.Log
 import android.widget.Toast
+import androidx.annotation.RequiresApi
 import androidx.appcompat.app.AppCompatActivity
+import androidx.core.content.ContextCompat
+import com.google.firebase.example.messaging.MainActivity
 import com.google.firebase.ktx.Firebase
 import com.google.firebase.messaging.ktx.messaging
 import com.google.firebase.messaging.ktx.remoteMessage
@@ -13,6 +18,7 @@ class MainActivity : AppCompatActivity() {
 
     companion object {
         private const val TAG = "MainActivity"
+        private const val NOTIFICATION_REQUEST_CODE = 1234
     }
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -90,4 +96,40 @@ class MainActivity : AppCompatActivity() {
         // [END log_reg_token]
     }
 
+    @RequiresApi(33)
+    // [START ask_post_notifications]
+    private fun askNotificationPermission() {
+        if (ContextCompat.checkSelfPermission(this, Manifest.permission.POST_NOTIFICATIONS) ==
+            PackageManager.PERMISSION_GRANTED
+        ) {
+            // FCM SDK (and your app) can post notifications.
+        } else if (shouldShowRequestPermissionRationale(Manifest.permission.POST_NOTIFICATIONS)) {
+            // TODO: display an educational UI explaining to the user the features that will be enabled
+            //       by them granting the POST_NOTIFICATION permission. This UI should provide the user
+            //       "OK" and "No thanks" buttons. If the user selects "OK" directly request the permission.
+            //       If the user selects "No thanks" allow the user to continue without notifications.
+        } else {
+            // Directly ask for the permission
+            requestPermissions(arrayOf(Manifest.permission.POST_NOTIFICATIONS), NOTIFICATION_REQUEST_CODE)
+        }
+    }
+    // [END ask_post_notifications]
+
+    // [START handle_ask_post_notifications_request]
+    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+        when (requestCode) {
+            NOTIFICATION_REQUEST_CODE -> {
+                // If request is cancelled, the result arrays are empty.
+                if (grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+                    // FCM SDK (and your app) can post notifications.
+                } else {
+                    // TODO: Inform user that that your app will not show notifications
+                }
+                return
+            }
+        }
+    }
+    // [END handle_ask_post_notifications_request]
+
 }