Continuously reading the change of a variable happens in one qml file in another qml file

[mamoud]

This post is deleted!

[mamoud]

This post is deleted!

[mamoud]

@dheerendra

Hi, thank you for your reply. Yeah what I want is:

1- When Up or Down buttons in Curve.qml is pressed, (modified) changes from false to true (that already happens correctly in Curve.qml)

2- I want to check this change in Screen.qml, i mean to check that modifeid is changed to true.
3- Based on this (modifeid is changed or not) i will take an action

I tried this:

I tried to add this part in curvepage in Screen.qml, but did not work as i want.

Screen.qml

        id: curvepage
        modified: false
        onModifiedChanged:{ if(curvepage.modified ===false){
                               curvepage.modified = true
                           }

and also i added to Curve.qml

Curve.qml

    signal modifiedChanged

But it seems i do something wrong

[dheerendra]

ok. No need to add modifiedChanged signal. When you declare any property it will have signal defined already. In your case modified is the property added. So it will have signal called modifiedChanged in Curve.qml

You should just call in Screen.qml

Curve {
         onModifiedChanged :{
                console.log(modified)
         }
}

This should work for you. Just check. If not I will give you sample program shortly.

[mamoud]

@dheerendra

Thanks again, but it did not work with me, I am not sure if this maybe a reason or not but in Screen.qml, the if condition is under onMainButtonPressed like this

Screen.qml

ScreenBase {
    id: root

       onMainButtonPressed: {

        if (button === "1"){ // a button when i press, what it does is either to show a popup warning that no changes in the curve have been done, or to activate a button without any warnings if changes happened to the curve.

            if (functions.func1) { // this is just to check if the function is set or not 
                if(curvepage.modified ===false){
                    showNotice = true // this shows a popup that no changes happened in the curve

                } else if(curvepage.modified === true) {
                    functions.functionPressed; // a button is pressed and shown pressed on screen and no popup warnings are shown
            }

            }
        }

}


will this cause a problem when i call (modified) from Curve object on the same Screen.qml?

It looks like it only reads the modified value that i set initially, I mean if in  Curve object I do like this:

    id: curvepage
    modified: true
    onModifiedChanged :{
            console.log(modified)
     }

}

it will perform the other option when modifeid is true

[dheerendra]

Check the following sample. Based on this you should be able to make your changes.

======Screen.qml =====
import QtQuick 2.11
import QtQuick.Window 2.11

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")
    MyCurve{
        id : curve
        onModifiedChanged: {
            console.log(modified)
        }
    }
}

============MyCurve.qml ==========

import QtQuick 2.0
import QtQuick.Controls 2.2

Rectangle {
    id : top
    width: 400;height: 400;color: "blue"
    property bool modified : false
    Row {
        Button{
            text :"True"
            onClicked: {
               top.modified=true;
            }
        }
        Button{
            text :"False"
            onClicked: {
               top.modified=false;
            }
        }
    }
}

[dheerendra]

@mamoud is the issue resolved ? Do you need help ?

[mamoud]

@dheerendra

Hi, thank you for this, but I still have the problem. modified state is not changed in Screen.qml file.

Here I can show you more detailed code, maybe i have another problem that cause this.

In Curve.qml

Rectangle {
    id: curvepage

    width: 320
    height: 240
    property bool modified: false // initially no changes happened in the curve
    // I want to check when modified is turned to true and read this change in Screen.qml 


         if (button === "up" || button === "down"  )
        {
            curvepage.modified = true;
        }

I guess no prolem here. But in Screen.qml, I have this:

Screen.qml

ScreenBase { // object from anothe qml file called **ScreenBase.qml**
    id: root

       onMainButtonPressed: {// from ScreenBase.qml file

        if (button === "1"){ // a button when i press, what it does is either to show a popup warning that no changes in the curve have been done, or to activate a button without any warnings if changes happened to the curve.

            if (functions.func1) { // this is just to check if the function is set or not 
                if(curvepage.modified ===false){
                    showNotice = true // this shows a popup that no changes happened in the curve

                } else if(curvepage.modified === true) {
                    functions.functionPressed; // a button is pressed and shown pressed on screen and no popup warnings are shown
            }

            }
        }

Curve{ // object is called inside **ScreenBase object** which is written in **Screen.qml file**

        id: curvepage
        modified: true
        onModifiedChanged :{
                console.log(modified)
         }
}

}

Does this make any problem while calling the variable (modified) from Curve.qml to Screen.qml. should i add anything in ScreenBase.qml??

The ScreenBase.qml file is a rectangle like this:

ScreenBase.qml

Rectangle {
    id: root
    width: 320
    height: 240
    clip: true 
// and some other buttons definitions

Also to clarify, When i press a butto to change a value on the curve, no matter if i increase or decrease, I just want to check if there is any change, so if i did not press any button, (modified) will be false, if i press any button (modified) will be true

Thank you very much for your help, but i am abit confused while dealing with those different files

[Tom_H]

@mamoud You have incorrectly initialized curvepage.modified to true in Screen.qml.

[mamoud]

@Tom_H
Hi thank you for reply,
but i have tried to delete it completely without any initalization in Curve object in Screen.qml, but still does not work