why property binding in dynamic component creation not working? - qt

Question

signal 'clearPinFromDevManager(const QString& pinn)' will be emited repeatedly from cpp file. the signal caught onClearPinFromDevManager:{},so everything in cpp and main.qml files are ok, but 'recvClearPin' does not bind to PasswordWindow.qml component which is created dynamicly.
Note:If code has a problem, what is your solution to fix the problem?thanks
Main.qml
import QtQuick 2.12
import QtQuick.Window 2.12
import Terminal 1.0
import QtQuick.Controls 2.12
ApplicationWindow {
id: rootId
visible: true
objectName: "window"
width: Screen.width
height: Screen.height
flags: Qt.FramelessWindowHint
property var component
property var object
property string recvClearPin:""
Rectangle {
id:rootRectId
width: rootId.width
height: rootId.height - headerId.height
color: "#000033"
}
Terminal {
id: terminalId
onSignalToInitTerminal:{
console.log("show Password window.")
component= Qt.createComponent("Ui/PasswordWindow.qml");
object=component.createObject(rootRectId,{clearPin: recvClearPin});
}
//signal will emit repeatedly
onClearPinFromDevManager:{
console.log("signal emited here and pinn is:",pinn)
recvClearPin=pinn
}
}
}
PasswordWindow.qml
import QtQuick 2.12
import QtQuick.Controls 2.12
import "../Definitions.js" as Definitions
Item {
id:passwordWindowId
width: parent.width
property string password: ""
property alias clearPin: textEditId.text
Text {
id: passwordWindowTextId
font.family: Definitions.LABEL_FONT_FAMILY; font.pointSize: Definitions.LABEL_POINT_SIZE
text: qsTr("لطفا رمز خود را وارد نمایید")
color: Definitions.LABEL_COLOR
y: Definitions.PAGE_TITLE_Y_POS
x: Definitions.PAGE_TITLE_X_POS
}
Rectangle {
id: textEditRectId
x: passwordWindowTextId.x +10
y: passwordWindowTextId.y + height
width: Definitions.TEXT_EDIT_WIDTH
height: Definitions.TEXT_EDIT_HEIGHT
border.width: 1
border.color: "#000000"
radius: 10
color: Definitions.GENERAL_COLOR
TextEdit {
id: textEditId
width: parent.width
height: parent.height
text: ""
font.family: Definitions.GENERAL_FONT_FAMILY; font.pointSize: Definitions.GENERAL_POINT_SIZE
color: "blue"
focus: true
verticalAlignment: TextEdit.AlignVCenter
horizontalAlignment: TextEdit.AlignHCenter
onTextChanged: {
console.log("texttttttttttttttttt:",text);
}
}
}
}

Answer 1

You do not bind the clearPin in this line: object=component.createObject(rootRectId,{clearPin: recvClearPin});. Instead you create a Json object with a item named 'clearPin' that has the current value of 'recvClearPin'. If you want a binding, use Qt.binding:
object=component.createObject(rootRectId,{clearPin: Qt.binding(function() { return recvClearPing} )});

Answer 2

please provide more information where signal clearPinFromDevManager(const QString& pinn) is connected.
For dynamic objects you should use connect syntax in QML with cpp-objects.
You need register your class wich contains clearPinFromDevManager(const QString& pinn) in QML, then connect it to dynamically created object, or in onComleted-handler, like this:
Declare yous class in CPP/H:
class CrearPinObject : public QObject {
Q_OBJECT
signals:
void clearPinFromDevManager(const QString& pinn);
}
Register it QML engine, main.cpp (or similar):
...
QQmlApplicationEngine engine;
engine.rootContext()->setContextProperty("CrearPinObjectView", new CrearPinObject);
...
Connect signal using QML-connect syntax (PasswordWindow.qml):
Item {
Component.onCompleted: {
// CrearPinObjectView-object forward automatically
CrearPinObjectView.clearPinFromDevManager.connect(clearPinFromDevManager);
}
function clearPinFromDevManager(pinn) {
console.log(pinn);
}
}
Hope helped!