Fix the problems with UI not reflecting the QtIvi backend changes

In current implementation the property bindings between QtIvi backend
properties and GUI object properties are used for two-way communication.
In case GUI requests a change, the requested GUI object property is assigned
with a new value. This operation removes property binding to the QtIvi
backend. Additional code in onXXXChanged: handler must be written explicitly
to propagate the change to the backend and recreate the binding afterwards.
This scheme is difficult to maintain and test.

In this modification a second channel is introduced - the property bindings
take care of propagation of updates from backend to GUI, and functions are
used by GUI in order to request backend changes. GUI itself does not update
it's own internal variables on user actions, and instead relies on property
bindings to follow the change in backend - this approach makes the code
simpler, avoids binding recreation, and handles well cases where backend
properties changes value to a different than assigned to it - backend can
react to property assignments in non-trivial ways.

Change-Id: I55423fe806d1db9d099c7983676dd1afeb1b5b69
Reviewed-by: Andreas Hartmetz <andreas.hartmetz@kdab.com>
Reviewed-by: Harri Porten <porten@froglogic.com>
Reviewed-by: Nedim Hadzic <nedim.hadzic@pelagicore.com>

4 files changed, 44 insertions, 61 deletions

diff --git a/imports/shared/service/climate/ClimateService.qml b/imports/shared/service/climate/ClimateService.qml
index ae8ce20..37e7480 100644
--- a/imports/shared/service/climate/ClimateService.qml
+++ b/imports/shared/service/climate/ClimateService.qml
@@ -49,17 +49,13 @@ QtObject {
 
         property bool heat: climateControl.zoneAt.FrontLeft.seatHeater.value
 
-        onValueChanged: climateControl.zoneAt.FrontLeft.targetTemperature.value = value
-        onHeatChanged: climateControl.zoneAt.FrontLeft.seatHeater.value = heat
-    }
-    property Connections leftSeatTargetTempConnections: Connections {
-        target: climateControl.zoneAt.FrontLeft.targetTemperature
-        onValueChanged: leftSeat.value =
-            calculateUnitValue(climateControl.zoneAt.FrontLeft.targetTemperature.value)
-    }
-    property Connections leftSeatHeaterConnections: Connections {
-        target: climateControl.zoneAt.FrontLeft.seatHeater
-        onValueChanged: leftSeat.heat = climateControl.zoneAt.FrontLeft.seatHeater.value
+        function setValue(newValue) {
+            climateControl.zoneAt.FrontLeft.targetTemperature.value = newValue
+        }
+
+        function setHeat(newHeat) {
+            climateControl.zoneAt.FrontLeft.seatHeater.value = newHeat
+        }
     }
 
     property QtObject rightSeat: QtObject {
@@ -70,36 +66,39 @@ QtObject {
 
         property bool heat: climateControl.zoneAt.FrontRight.seatHeater.value
 
-        onValueChanged: climateControl.zoneAt.FrontRight.targetTemperature.value = value
-        onHeatChanged: climateControl.zoneAt.FrontRight.seatHeater.value = heat
-    }
-    property Connections rightSeatTargetTempConnections: Connections {
-        target: climateControl.zoneAt.FrontRight.targetTemperature
-        onValueChanged: rightSeat.value =
-            calculateUnitValue(climateControl.zoneAt.FrontRight.targetTemperature.value)
-    }
-    property Connections rightSeatHeaterConnections: Connections {
-        target: climateControl.zoneAt.FrontRight.seatHeater
-        onValueChanged: rightSeat.heat = climateControl.zoneAt.FrontRight.seatHeater.value
+        function setValue(newValue) {
+            climateControl.zoneAt.FrontRight.targetTemperature.value = newValue
+        }
+
+        function setHeat(newHeat) {
+            climateControl.zoneAt.FrontRight.seatHeater.value = newHeat
+        }
     }
 
     property QtObject frontHeat: QtObject {
         property string symbol: "front"
         property bool enabled: true
+
+        function setEnabled(newEnabled) {
+            enabled = newEnabled;
+        }
     }
 
     property QtObject rearHeat: QtObject {
         property string symbol: "rear"
         property bool enabled: true
+
+        function setEnabled(newEnabled) {
+            enabled = newEnabled;
+        }
     }
 
     property QtObject airCondition: QtObject {
         property string symbol: "ac"
         property bool enabled: climateControl.airConditioning.value
 
-        onEnabledChanged: {
-            climateControl.airConditioning.value = enabled;
-            enabled = Qt.binding(function() { return climateControl.airConditioning.value; });
+        function setEnabled(newEnabled) {
+            climateControl.airConditioning.value = newEnabled;
         }
     }
 
@@ -107,24 +106,26 @@ QtObject {
         property string symbol: "air_quality"
         property bool enabled: climateControl.recirculationMode.value == ClimateControl.RecirculationOn
 
-        onEnabledChanged: {
-            climateControl.recirculationMode.value = enabled ? ClimateControl.RecirculationOn : ClimateControl.RecirculationOff;
-            enabled = Qt.binding(function() { return climateControl.recirculationMode.value == ClimateControl.RecirculationOn });
+        function setEnabled(newEnabled) {
+            climateControl.recirculationMode.value = newEnabled ? ClimateControl.RecirculationOn : ClimateControl.RecirculationOff;
         }
     }
 
     property QtObject eco: QtObject {
         property string symbol: "eco"
         property bool enabled: false
+
+        function setEnabled(newEnabled) {
+            enabled = newEnabled;
+        }
     }
 
     property QtObject steeringWheelHeat: QtObject {
         property string symbol: "stearing_wheel"
         property bool enabled: climateControl.steeringWheelHeater.value >= 5
 
-        onEnabledChanged: {
-            climateControl.steeringWheelHeater.value = enabled ? 10 : 0;
-            enabled = Qt.binding(function() { return climateControl.steeringWheelHeater.value >= 5 });
+        function setEnabled(newEnabled) {
+            climateControl.steeringWheelHeater.value = newEnabled ? 10 : 0;
         }
     }
 
@@ -136,10 +137,8 @@ QtObject {
     property string tempSuffix: SettingsService.metric ? "°C" : "°F"
     property int ventilationLevels: 7 // 6 + off (0)
 
-    onVentilationChanged: climateControl.fanSpeedLevel.value = ventilation
-    property Connections fanSpeedLevelConnections: Connections {
-        target: climateControl.fanSpeedLevel
-        onValueChanged: ventilation = climateControl.fanSpeedLevel.value
+    function setVentilation(newVentilation) {
+        climateControl.fanSpeedLevel.value = newVentilation;
     }
 
     property QtObject stateMachine: ClimateStateMachine {
diff --git a/imports/shared/service/climate/ClimateStateMachine.qml b/imports/shared/service/climate/ClimateStateMachine.qml
index 2b36520..bfc9925 100644
--- a/imports/shared/service/climate/ClimateStateMachine.qml
+++ b/imports/shared/service/climate/ClimateStateMachine.qml
@@ -73,7 +73,7 @@ QtObject {
                             id: airConditionOn
                             onEntered: {
                                 climateControl.airConditioning.value = true
-                                steeringWheelHeat.enabled = false
+                                steeringWheelHeat.setEnabled(false)
                             }
                             DSM.SignalTransition {
                                 targetState: airConditionOff
diff --git a/sysui/Climate/ClimateBar.qml b/sysui/Climate/ClimateBar.qml
index f391b6c..a300400 100644
--- a/sysui/Climate/ClimateBar.qml
+++ b/sysui/Climate/ClimateBar.qml
@@ -89,7 +89,7 @@ UIElement {
                 vspan: root.collapsedVspan
                 name: "seat_left"
                 active: ClimateService.leftSeat.heat
-                onClicked: ClimateService.leftSeat.heat = !active
+                onClicked: ClimateService.leftSeat.setHeat(!active)
                 anchors.left: tempLevelLeft.right
                 anchors.verticalCenter: parent.verticalCenter
             }
@@ -108,7 +108,7 @@ UIElement {
                 vspan: root.collapsedVspan
                 name: "seat_right"
                 active: ClimateService.rightSeat.heat
-                onClicked: ClimateService.rightSeat.heat = !active
+                onClicked: ClimateService.rightSeat.setHeat(!active)
                 anchors.right: tempLevelRight.left
                 anchors.verticalCenter: parent.verticalCenter
             }
@@ -135,7 +135,7 @@ UIElement {
                 maxValue: ClimateService.leftSeat.maxValue
                 value: ClimateService.leftSeat.value
                 stepValue: ClimateService.leftSeat.stepValue
-                onValueChanged: ClimateService.leftSeat.value = value
+                onValueChanged: ClimateService.leftSeat.setValue(value)
             }
 
             Spacer {
@@ -161,11 +161,7 @@ UIElement {
                     vspan: 2
                     levels: ClimateService.ventilationLevels
                     currentLevel: ClimateService.ventilation
-                    onCurrentLevelChanged: ClimateService.ventilation = currentLevel
-                    Connections {
-                        target: ClimateService
-                        onVentilationChanged: ventilation.currentLevel = ClimateService.ventilation
-                    }
+                    onNewLevelRequested: ClimateService.setVentilation(newLevel)
                 }
 
                 Spacer {
@@ -184,7 +180,7 @@ UIElement {
                         vspan: 5
                         symbolName: modelData.symbol
                         active: modelData.enabled
-                        onClicked: modelData.enabled = !modelData.enabled
+                        onClicked: modelData.setEnabled(!modelData.enabled)
                     }
                 }
             }
@@ -203,7 +199,7 @@ UIElement {
                 maxValue: ClimateService.rightSeat.maxValue
                 value: ClimateService.rightSeat.value
                 stepValue: ClimateService.rightSeat.stepValue
-                onValueChanged: ClimateService.rightSeat.value = value
+                onValueChanged: ClimateService.rightSeat.setValue(value)
             }
 
         }
@@ -214,13 +210,4 @@ UIElement {
         }
     }
 
-    Connections {
-        target: ClimateService.leftSeat
-        onValueChanged: leftTempSlider.value = ClimateService.leftSeat.value
-    }
-
-    Connections {
-        target: ClimateService.rightSeat
-        onValueChanged: rightTempSlider.value = ClimateService.rightSeat.value
-    }
 }
diff --git a/sysui/Climate/Ventilation.qml b/sysui/Climate/Ventilation.qml
index c6f4bfa..f71f80e 100644
--- a/sysui/Climate/Ventilation.qml
+++ b/sysui/Climate/Ventilation.qml
@@ -40,16 +40,13 @@ UIElement {
     property int levels
     property int currentLevel
 
-    property bool _updateInProgress: false
+    onCurrentLevelChanged: view.currentIndex = currentLevel;
 
-    onCurrentLevelChanged: if (!_updateInProgress) updateLevelInternal(currentLevel);
+    signal newLevelRequested(int newLevel)
 
     function updateLevelInternal(newLevel) {
         var boundedLevel = Math.max(0, Math.min(levels - 1, newLevel));
-        _updateInProgress = true;
-        currentLevel = boundedLevel;
-        _updateInProgress = false;
-        view.currentIndex = boundedLevel;
+        newLevelRequested( boundedLevel );
     }
 
     MouseArea {