Fix disappearing slider during size/orientation change

Now the slider remains at a position that is equivalent to the old
position based on the previous percentage.

This change is most commonly triggered during orientation changes on
mobile device. That is the reason why the app was converted to a
proper Qt project. This way it was possible to test this behavior
on Android.

Task-number: QTBUG-18423
Change-Id: If05e6a1e42249f90a821c4882021d28cf212fc52
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

1 files changed, 16 insertions, 3 deletions

diff --git a/examples/quick/customitems/dialcontrol/dialcontrol.qml b/examples/quick/customitems/dialcontrol/dialcontrol.qml
index f545877655..0bf6d7e68c 100644
--- a/examples/quick/customitems/dialcontrol/dialcontrol.qml
+++ b/examples/quick/customitems/dialcontrol/dialcontrol.qml
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the examples of the Qt Toolkit.
@@ -39,7 +39,8 @@
 ****************************************************************************/
 
 //! [imports]
-import QtQuick 2.0
+import QtQuick 2.2
+import QtQuick.Window 2.1
 import "content"
 //! [imports]
 
@@ -53,12 +54,13 @@ Rectangle {
     Dial {
         id: dial
         anchors.centerIn: parent
-        value: slider.x * 100 / (container.width - 34)
+        value: slider.x * 100 / (container.width - 32)
     }
     //! [the dial in use]
 
     Rectangle {
         id: container
+        property int oldWidth: 0
         anchors { bottom: parent.bottom; left: parent.left
             right: parent.right; leftMargin: 20; rightMargin: 20
             bottomMargin: 10
@@ -73,6 +75,17 @@ Rectangle {
             GradientStop { position: 1.0; color: "white" }
         }
 
+        onWidthChanged: {
+            if (oldWidth === 0) {
+                oldWidth = width;
+                return
+            }
+
+            var desiredPercent = slider.x * 100 / (oldWidth - 32)
+            slider.x = desiredPercent * (width - 32) / 100
+            oldWidth = width
+        }
+
         Rectangle {
             id: slider
             x: 1; y: 1; width: 30; height: 14