ui: add descriptions to notification channels (#395)

* ui: add descriptions to notification channels

Provide descriptions that will be displayed in the Android system notification settings to describe the purpose of each notification channel to the user.

* Use IMPORTANCE_HIGH for start_vpn_channel

android/src/main/java/com/tailscale/ipn/App.kt

@@ -93,9 +93,15 @@ class App : UninitializedApp(), libtailscale.AppContext {
   override fun onCreate() {
     super.onCreate()
     createNotificationChannel(
-        STATUS_CHANNEL_ID, "VPN Status", NotificationManagerCompat.IMPORTANCE_LOW)
+        STATUS_CHANNEL_ID,
+        getString(R.string.vpn_status),
+        getString(R.string.optional_notifications_which_display_the_status_of_the_vpn_tunnel),
+        NotificationManagerCompat.IMPORTANCE_MIN)
     createNotificationChannel(
-        FILE_CHANNEL_ID, "File transfers", NotificationManagerCompat.IMPORTANCE_DEFAULT)
+        FILE_CHANNEL_ID,
+        getString(R.string.taildrop_file_transfers),
+        getString(R.string.notifications_delivered_when_a_file_is_received_using_taildrop),
+        NotificationManagerCompat.IMPORTANCE_DEFAULT)
     appInstance = this
     setUnprotectedInstance(this)
   }
@@ -393,8 +399,9 @@ open class UninitializedApp : Application() {
     startService(intent)
   }
 
-  fun createNotificationChannel(id: String?, name: String?, importance: Int) {
+  fun createNotificationChannel(id: String, name: String, description: String, importance: Int) {
     val channel = NotificationChannel(id, name, importance)
+    channel.description = description
     val nm: NotificationManagerCompat = NotificationManagerCompat.from(this)
     nm.createNotificationChannel(channel)
   }

android/src/main/java/com/tailscale/ipn/StartVPNWorker.java

@@ -45,7 +45,7 @@ public final class StartVPNWorker extends Worker {
         String channelId = "start_vpn_channel";
 
         // Use createNotificationChannel method from App.java
-        app.createNotificationChannel(channelId, "Start VPN Channel", NotificationManager.IMPORTANCE_DEFAULT);
+        app.createNotificationChannel(channelId, getApplicationContext().getString(R.string.vpn_start), getApplicationContext().getString(R.string.notifications_delivered_when_user_interaction_is_required_to_establish_the_vpn_tunnel), NotificationManager.IMPORTANCE_HIGH);
 
         // Use prepareIntent if available.
         Intent intent = app.getPackageManager().getLaunchIntentForPackage(app.getPackageName());

android/src/main/res/values/strings.xml

@@ -246,4 +246,12 @@
     <!-- Strings for the IPNReceiver -->
     <string name="title_connection_failed">Tailscale Connection Failed</string>
     <string name="body_open_tailscale">Tap here to open Tailscale.</string>
+
+    <!-- Strings describing notification channels -->
+    <string name="taildrop_file_transfers">Taildrop file transfers</string>
+    <string name="vpn_status">VPN status</string>
+    <string name="vpn_start">VPN start</string>
+    <string name="notifications_delivered_when_user_interaction_is_required_to_establish_the_vpn_tunnel">Notifications delivered when user interaction is required to establish the VPN tunnel.</string>
+    <string name="optional_notifications_which_display_the_status_of_the_vpn_tunnel">Optional notifications which display the status of the VPN tunnel.</string>
+    <string name="notifications_delivered_when_a_file_is_received_using_taildrop">Notifications delivered when a file is received using Taildrop.</string>
 </resources>