Prevent recreating monitor MenuItem

mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringFragment.kt

@@ -25,6 +25,7 @@ import be.mygod.vpnhotspot.net.TetheringManager.localOnlyTetheredIfaces
 import be.mygod.vpnhotspot.net.TetheringManager.tetheredIfaces
 import be.mygod.vpnhotspot.util.ServiceForegroundConnector
 import be.mygod.vpnhotspot.util.broadcastReceiver
+import be.mygod.vpnhotspot.util.isNotGone
 import kotlinx.android.synthetic.main.activity_main.*
 import timber.log.Timber
 import java.net.NetworkInterface
@@ -95,20 +96,13 @@ class TetheringFragment : Fragment(), ServiceConnection, MenuItem.OnMenuItemClic
     }
 
     private fun updateMonitorList(canMonitor: List<String> = emptyList()) {
-        val toolbar = requireActivity().toolbar
-        val menu = toolbar.menu
-        if (canMonitor.isEmpty()) menu.removeItem(R.id.monitor) else {
-            var item = menu.findItem(R.id.monitor)
-            if (item == null) {
-                toolbar.inflateMenu(R.menu.toolbar_monitor)
-                item = menu.findItem(R.id.monitor)!!
-            }
+        val item = requireActivity().toolbar.menu.findItem(R.id.monitor) ?: return  // assuming no longer foreground
+        item.isNotGone = canMonitor.isNotEmpty()
         item.subMenu.apply {
             clear()
             canMonitor.sorted().forEach { add(it).setOnMenuItemClickListener(this@TetheringFragment) }
         }
     }
-    }
     override fun onMenuItemClick(item: MenuItem?): Boolean {
         ContextCompat.startForegroundService(requireContext(), Intent(context, TetheringService::class.java)
                 .putExtra(TetheringService.EXTRA_ADD_INTERFACE_MONITOR, item?.title ?: return false))
@@ -123,9 +117,15 @@ class TetheringFragment : Fragment(), ServiceConnection, MenuItem.OnMenuItemClic
         binding.interfaces.adapter = adapter
         adapter.update(emptyList(), emptyList(), emptyList())
         ServiceForegroundConnector(this, this, TetheringService::class)
+        requireActivity().toolbar.inflateMenu(R.menu.toolbar_tethering)
         return binding.root
     }
 
+    override fun onDestroyView() {
+        super.onDestroyView()
+        requireActivity().toolbar.menu.clear()
+    }
+
     override fun onResume() {
         super.onResume()
         if (Build.VERSION.SDK_INT >= 27) ManageBar.Data.notifyChange()
@@ -163,9 +163,4 @@ class TetheringFragment : Fragment(), ServiceConnection, MenuItem.OnMenuItemClic
         binder = null
         requireContext().unregisterReceiver(receiver)
     }
-
-    override fun onDestroy() {
-        updateMonitorList()
-        super.onDestroy()
-    }
 }

mobile/src/main/java/be/mygod/vpnhotspot/util/Utils.kt

@@ -5,6 +5,7 @@ import android.os.Build
 import android.text.Spannable
 import android.text.SpannableString
 import android.text.SpannableStringBuilder
+import android.view.MenuItem
 import android.view.View
 import android.widget.ImageView
 import androidx.annotation.DrawableRes
@@ -91,6 +92,13 @@ fun Context.stopAndUnbind(connection: ServiceConnection) {
     unbindService(connection)
 }
 
+var MenuItem.isNotGone: Boolean
+    get() = isVisible || isEnabled
+    set(value) {
+        isVisible = value
+        isEnabled = value
+    }
+
 fun <K, V> MutableMap<K, V>.computeIfAbsentCompat(key: K, value: () -> V) = if (Build.VERSION.SDK_INT >= 24)
     computeIfAbsent(key) { value() } else this[key] ?: value().also { put(key, it) }
 fun <K, V> MutableMap<K, V>.putIfAbsentCompat(key: K, value: V) = if (Build.VERSION.SDK_INT >= 24)

mobile/src/main/res/menu/toolbar_tethering.xml

@@ -4,6 +4,8 @@
     <item android:id="@+id/monitor"
           android:icon="@drawable/ic_image_remove_red_eye"
           android:title="@string/tethering_monitor"
+          android:enabled="false"
+          android:visible="false"
           app:showAsAction="always">
         <menu/>
     </item>