How to save the state of qml file using c++

[arlyn123]

I am working on game and I want to save the game window using c++. I want make a method ofr that and in qml I will call that method. How can I save the state and geometry of that window?

[jeremy_k]

Is using C++ an important part of the goal?

If not, Settings provides a way to read and write data backed by an OS dependent mechanism.

[arlyn123]

@jeremy_k not really. I want to do it in a simple way

[Bondrusiek]

@arlyn123 hi! You can also see on QSettings(https://doc.qt.io/qt-6/qsettings.html) if you use C++.

[jeremy_k]

import QtQuick.Window
import QtQuick.Controls
import QtCore

Window {
    id: win
    visible: true

    Component.onCompleted: {
        var geometry = settings.value("windowPosition");
        if (geometry) {
            var saved = JSON.parse(geometry);
            win.x = saved.x;
            win.y = saved.y;
            win.width = saved.width;
            win.height = saved.height;
        }
    }

    Button {
        anchors.centerIn: win.contentItem
        text: "push to save"
        onClicked: settings.setValue("windowPosition",
            JSON.stringify({"x": win.x, "y": win.y, "width": win.width, "height": win.height }));
    }

    Settings {
        id: settings
        location: "file:///tmp/test"
    }
}

[arlyn123]

@jeremy_k I have two qml files. I want to save on them using a button onClick. How can I do that? The one in that I want to save the other window is connected my a main.qml that has a window and a loader.

import QtQuick
import QtQuick.Window
import QtQuick.Controls 6.0

Window {
    width: 1920
    height: 1080
    visible: true
    title: qsTr("Main Menu")

    Loader {
        id: mainLoader
        anchors.fill: parent
        source: "qrc:/UI/screens/HomeScreen.qml"
    }
}

HomeScreen has an item and other elements inside it. As well as the button that I want to click. Is possible to have the second window using that button that it is in HomeScreen?

[jeremy_k]

@arlyn123 said in How to save the state of qml file using c++:

HomeScreen has an item and other elements inside it. As well as the button that I want to click. Is possible to have the second window using that button that it is in HomeScreen?

The clean way is to have HomeScreen emit a signal with the properties to be saved. If the properties are generic and externally visible, these can be skipped.

In main.qml, use a Connections to connect to the signal and save the data. The Loader documentation gives an example of printing a message when signal is emitted from a loaded item.

[arlyn123]

@jeremy_k how can I use a connection to actually restore the window that I want to save and to make the loader to still open HomeScreen.qml? that's my biggest problem right now. I have created a signal and emited in the button. And now?

Button {
        id: loadGame
        x: 81
        y: 284

        width: 154
        height: 34
        onClicked: {
            loadSignal.emit()
        }
        
        text: "Load Game"
        background: Rectangle {
            color: "transparent"
        }

        contentItem: Text {
            color: loadGame.hovered ? "#a9caf9" : "#ffffff"
            text: "Load Game"
            font.family: "Inria Serif"
            font.pixelSize: 26
            horizontalAlignment: Text.AlignLeft
            verticalAlignment: Text.AlignTop
            wrapMode: Text.Wrap
            font.weight: Font.Normal
        }
    }
    
    signal loadSignal();

[jeremy_k]

@arlyn123 said in How to save the state of qml file using c++:

@jeremy_k how can I use a connection to actually restore the window that I want to save and to make the loader to still open HomeScreen.qml?

You might find Loader.setSource(url source, object properties) useful to specify the component to load as well as its properties to restore.

[BogDan Vatra]

@arlyn123 did you find any solution?