Use OpacityAnimators instead of NumberAnimations

src/qml/Base/HButtonBackground.qml

@@ -11,7 +11,7 @@ Rectangle {
     property QtObject buttonTheme
 
 
-    Behavior on opacity { HNumberAnimation {} }
+    Behavior on opacity { HOpacityAnimator {} }
 
 
     Rectangle {

src/qml/Base/HButtonContent.qml

@@ -16,7 +16,7 @@ HRowLayout {
     readonly property alias label: label
 
 
-    Behavior on opacity { HNumberAnimation {} }
+    Behavior on opacity { HOpacityAnimator {} }
 
 
     HIcon {
@@ -35,7 +35,7 @@ HRowLayout {
 
         ParallelAnimation {
             id: resetAnimations
-            HNumberAnimation { target: icon; property: "opacity"; to: 1 }
+            HOpacityAnimator { target: icon; to: 1 }
             HNumberAnimation { target: icon; property: "rotation"; to: 0 }
         }
 

src/qml/Base/HCheckBox.qml

@@ -17,7 +17,7 @@ CheckBox {
     property alias subtitle: subtitleText
 
 
-    Behavior on opacity { HNumberAnimation { factor: 2 } }
+    Behavior on opacity { HOpacityAnimator { factor: 2 } }
 
 
     indicator: Rectangle {

src/qml/Base/HListView.qml

@@ -31,7 +31,7 @@ ListView {
 
     add: Transition {
         ParallelAnimation {
-            HNumberAnimation { property: "opacity"; from: 0; to: 1 }
+            HOpacityAnimator { from: 0; to: 1 }
             HNumberAnimation { properties: "x,y"; from: 100 }
         }
     }
@@ -39,14 +39,14 @@ ListView {
     move: Transition {
         ParallelAnimation {
             // Ensure opacity goes to 1 if add/remove transition is interrupted
-            HNumberAnimation { property: "opacity"; to: 1 }
+            HOpacityAnimator { to: 1 }
             HNumberAnimation { properties: "x,y" }
         }
     }
 
     remove: Transition {
         ParallelAnimation {
-            HNumberAnimation { property: "opacity"; to: 0 }
+            HOpacityAnimator { to: 0 }
             HNumberAnimation { properties: "x,y"; to: 100 }
         }
     }

src/qml/Base/HOpacityAnimator.qml

@@ -0,0 +1,7 @@
+import QtQuick 2.12
+
+OpacityAnimator {
+    duration: theme.animationDuration * factor
+
+    property real factor: 1.0
+}