Make effective property alias, using Connections, Binding or Qt.binding - qt

Question

Is it possible to make mutual connection (without loop issue), using Connections, Binding or Qt.binding()?
It is possible to connect, say, SwipeView.currentIndex to TabBar.currentIndex and vise versa. When I page through SwipeView, then current tab of TabBar is also changed and vice versa. There is no binding loop of properties.
How to achieve this in Repeater? When some item created by Repeater became selected (in some sense), then I want to rebind its properties to another standalone item, which operates like editor of the selected item. The state of elements in selected item should depend on the state of items into the editor. But on selection changing I need to initialize items in editor using values from newly selected item.
import QtQuick 2.7
import QtQuick.Controls 2.1
import QtQuick.Layouts 1.3
import Qt.labs.settings 1.0
ApplicationWindow {
id: root
property var currentDayOfWeek: { "enabled": false, "time": "08:00" }
visible: true
SystemPalette {
id: palette
}
RowLayout {
anchors.centerIn: parent
Column {
ButtonGroup { id: weekButtonGroup }
Repeater {
model: 7
RowLayout {
Settings {
id: dayOfWeekSettings
category: Qt.locale("C").standaloneDayName(index, Locale.LongFormat)
property bool enabled: false
property string time: "08:00"
}
Label {
text: dayOfWeekSettings.time
verticalAlignment: Text.AlignVCenter
horizontalAlignment: Text.AlignHCenter
background: Rectangle {
color: dayOfWeekSettings.enabled ? palette.highlight : palette.base
}
Layout.fillHeight: true
}
RadioButton {
text: Qt.locale().standaloneDayName(index, Locale.LongFormat)
onCheckedChanged: {
if (checked) {
root.currentDayOfWeek = dayOfWeekSettings
timeField.text = Qt.binding(function() { return dayOfWeekSettings.time }) // ???
enabledCheckBox.checked = Qt.binding(function() { return dayOfWeekSettings.enabled }) // ???
}
}
ButtonGroup.group: weekButtonGroup
Layout.fillHeight: true
}
}
}
Layout.fillHeight: true
}
Column {
// Editor
TextField {
id: timeField
text: currentDayOfWeek.time // ???
inputMask: "00:00;_"
inputMethodHints: Qt.ImhDigitsOnly
}
CheckBox {
id: enabledCheckBox
checked: currentDayOfWeek.enabled // ???
}
Layout.fillHeight: true
}
}
}
How to achieve this? Is there canonical way to do this? Above example is not the solution.

Answer 1

The following code works as I want:
import QtQuick 2.7
import QtQuick.Controls 2.1
import QtQuick.Layouts 1.3
import Qt.labs.settings 1.0
ApplicationWindow {
id: root
//property var currentDayOfWeek: { "enabled": false, "time": "08:00" }
visible: true
SystemPalette {
id: palette
}
RowLayout {
anchors.centerIn: parent
Column {
ButtonGroup { id: weekButtonGroup }
Repeater {
model: 7
RowLayout {
Settings {
id: dayOfWeekSettings
category: Qt.locale("C").standaloneDayName(index, Locale.LongFormat)
property bool enabled: false
property string time: "08:00"
Binding on enabled {
when: dayOfWeekSettingsCheckBox.checked
value: enabledCheckBox.checked
}
Binding on time {
when: dayOfWeekSettingsCheckBox.checked
value: timeField.text
}
}
Label {
text: dayOfWeekSettings.time
verticalAlignment: Text.AlignVCenter
horizontalAlignment: Text.AlignHCenter
background: Rectangle {
color: dayOfWeekSettings.enabled ? palette.highlight : palette.base
}
Layout.fillHeight: true
}
RadioButton {
id: dayOfWeekSettingsCheckBox
text: Qt.locale().standaloneDayName(index, Locale.LongFormat)
onCheckedChanged: {
if (checked) {
//root.currentDayOfWeek = dayOfWeekSettings
timeField.text = dayOfWeekSettings.time
enabledCheckBox.checked = dayOfWeekSettings.enabled
}
}
ButtonGroup.group: weekButtonGroup
Layout.fillHeight: true
}
}
}
Layout.fillHeight: true
}
Column {
id: editor
TextField {
id: timeField
//text: currentDayOfWeek.time
inputMask: "00:00;_"
inputMethodHints: Qt.ImhDigitsOnly
}
CheckBox {
id: enabledCheckBox
//checked: currentDayOfWeek.enabled
}
Layout.fillHeight: true
}
}
}
but there is an issue: editor filled with values in onCheckedChanged when checked became true. But what if when: in Bindings shoot first? Is it possible? Should I use delayed?
If I comment out:
timeField.text = dayOfWeekSettings.time
enabledCheckBox.checked = dayOfWeekSettings.enabled
and uncomment all the commented in above solution, then also all works fine. But the suspicion still persist.