QtQuick2 dragging frameless window

Question

I’m looking for a way of dragging frameless window in QtQuick2. I followed this thread on the forum Link but it gives me an error.

Main difference in the code is that my code uses QtQuick2ApplicationViewer instead of QmlApplicationViewer and it looks like QtQuick2ApplicationViewer do not have “.pos” property.

This is my main.cpp

#include <QtGui/QGuiApplication>
#include "qtquick2applicationviewer.h"
#include <QQmlContext>

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);

    QtQuick2ApplicationViewer viewer;
    viewer.rootContext()->setContextProperty("QmlApplicationViewer", (QObject *)&viewer);
    viewer.setFlags(Qt::FramelessWindowHint);
    viewer.setMainQmlFile(QStringLiteral("qml/ubusell/main.qml"));
    viewer.showExpanded();

    return app.exec();
}

This is part of my main.qml

MouseArea {
    id: mouseRegion
    anchors.fill: parent;
    property variant clickPos: "1,1"

        onPressed: {
            clickPos  = Qt.point(mouse.x,mouse.y)
        }

        onPositionChanged: {
            var delta = Qt.point(mouse.x-clickPos.x, mouse.y-clickPos.y)
            print(QmlApplicationViewer.pos)
            QmlApplicationViewer.pos = (20,20)
            QmlApplicationViewer.pos = Qt.point(QmlApplicationViewer.pos.x+delta.x,
                              QmlApplicationViewer.pos.y+delta.y)
        }
}

When I try to drag window I get this error:

TypeError: Cannot read property 'x' of undefined

Any ideas ? Is it even possible with QtQuick2 ? Thanks for help!

Answer 1

In my project I do:

property variant clickPos: "1,1"

onPressed: {
    clickPos  = Qt.point(mouse.x,mouse.y)
}

onPositionChanged: {
    var delta = Qt.point(mouse.x-clickPos.x, mouse.y-clickPos.y)
    rootWindow.x += delta.x;
    rootWindow.y += delta.y;
}

In MouseArea.

Answer 2

Also to resemble Windows behaviour of maximizing window when dragging it above vertical edge of the screen:

MouseArea {
    anchors.fill: parent;
    property variant clickPos: "1,1"

    onPressed: {
        clickPos = Qt.point(mouse.x,mouse.y)
    }

    onPositionChanged: {
        var delta = Qt.point(mouse.x-clickPos.x, mouse.y-clickPos.y)
        var new_x = mainWindow.x + delta.x
        var new_y = mainWindow.y + delta.y
        if (new_y <= 0)
            mainWindow.visibility = Window.Maximized
        else
        {
            if (mainWindow.visibility === Window.Maximized)
                mainWindow.visibility = Window.Windowed
            mainWindow.x = new_x
            mainWindow.y = new_y
        }
    }
}

Answer 3

I done it as follow:

Window {
    id: window
    height: 400
    width: 250
    x: (Screen.width - width)/2     //<---start position of window
    y: (Screen.height - height)/2   //<-┘
    color: "transparent"
    flags: Qt.MSWindowsFixedSizeDialogHint | Qt.FramelessWindowHint

    MouseArea {
        anchors.fill: parent
        property point lastMousePos: Qt.point(0, 0)
        onPressed: { lastMousePos = Qt.point(mouseX, mouseY); }
        onMouseXChanged: window.x += (mouseX - lastMousePos.x)
        onMouseYChanged: window.y += (mouseY - lastMousePos.y)
    }

    Item {
        id: myFirstPage
        anchors.fill: parent
        anchors.topMargin: 50
        //...
        //This item can have some mouse area
    }
}

Now you can move window using dragging top 50 pixels or any where that is not under any MouseArea.

Answer 4

A rather complete example:

import QtQuick 2.14
import QtQuick.Controls 2.14

ApplicationWindow {
    visible: true
    width: 200
    height: 200
    flags: Qt.FramelessWindowHint
    MouseArea {
        anchors.fill: parent
        onPressed: { pos = Qt.point(mouse.x, mouse.y) }
        onPositionChanged: {
            var diff = Qt.point(mouse.x - pos.x, mouse.y - pos.y)
            ApplicationWindow.window.x += diff.x
            ApplicationWindow.window.y += diff.y
        }
        property point pos
    }
}