Avoid polling if the Qt window is minimized

app/gui/AppView.qml

@@ -36,15 +36,9 @@ GridView {
 
     onVisibleChanged: {
         if (visible) {
-            // Start polling when this view is shown
-            ComputerManager.startPolling()
-
             appModel.computerLost.connect(computerLost)
         }
         else {
-            // Stop polling when this view is not on top
-            ComputerManager.stopPollingAsync()
-
             appModel.computerLost.disconnect(computerLost)
         }
     }

app/gui/PcView.qml

@@ -2,6 +2,7 @@ import QtQuick 2.9
 import QtQuick.Controls 2.2
 import QtQuick.Dialogs 1.3
 import QtQuick.Layouts 1.3
+import QtQuick.Window 2.2
 
 import ComputerModel 1.0
 
@@ -42,25 +43,11 @@ GridView {
         }
     }
 
-    onVisibleChanged: {
-        if (visible) {
-            // Start polling when this view is shown
-            ComputerManager.startPolling()
-        }
-        else {
-            // Stop polling when this view is not top-most
-            ComputerManager.stopPollingAsync()
-        }
-    }
-
     function pairingComplete(error)
     {
         // Close the PIN dialog
         pairDialog.close()
 
-        // Start polling again
-        ComputerManager.startPolling()
-
         // Display a failed dialog if we got an error
         if (error !== null) {
             errorDialog.text = error
@@ -176,9 +163,6 @@ GridView {
                             if (!model.busy) {
                                 var pin = ("0000" + Math.floor(Math.random() * 10000)).slice(-4)
 
-                                // Stop polling, since pairing may make GFE unresponsive
-                                ComputerManager.stopPollingAsync()
-
                                 // Kick off pairing in the background
                                 computerModel.pairComputer(index, pin)
 

app/gui/QuitSegue.qml

@@ -44,16 +44,10 @@ Item {
         if (visible) {
             // Connect the quit completion signal
             ComputerManager.quitAppCompleted.connect(quitAppCompleted)
-
-            // We must be polling or we won't get the quitAppCompleted() callback
-            ComputerManager.startPolling()
         }
         else {
             // Disconnect the signal
             ComputerManager.quitAppCompleted.disconnect(quitAppCompleted)
-
-            // Stop polling when this view is not on top
-            ComputerManager.stopPollingAsync()
         }
     }
 

app/gui/main.qml

@@ -1,12 +1,16 @@
 import QtQuick 2.9
 import QtQuick.Controls 2.2
 import QtQuick.Layouts 1.3
+import QtQuick.Window 2.2
 
 import QtQuick.Controls.Material 2.1
 
+import ComputerManager 1.0
 import AutoUpdateChecker 1.0
 
 ApplicationWindow {
+    property bool pollingActive: false
+
     id: window
     visible: true
     width: 1280
@@ -21,6 +25,24 @@ ApplicationWindow {
         anchors.fill: parent
     }
 
+    onVisibilityChanged: {
+        // We don't want to just use 'active' here because that will stop polling if
+        // we lose focus, which might be overzealous for users with multiple screens
+        // where we may be clearly visible on the other display. Ideally we'll poll
+        // only if the window is visible to the user (not if obscured by other windows),
+        // but it seems difficult to do this portably.
+        var shouldPoll = visibility !== Window.Minimized && visibility !== Window.Hidden
+
+        if (shouldPoll && !pollingActive) {
+            ComputerManager.startPolling()
+            pollingActive = true
+        }
+        else if (!shouldPoll && pollingActive) {
+            ComputerManager.stopPollingAsync()
+            pollingActive = false
+        }
+    }
+
     function navigateTo(url, objectName)
     {
         var existingItem = stackView.find(function(item, index) {