[SOLVED] mousePressEvent in QtQuickView

fcarney

Show us a minimal class and qml file the view is used in. Examples don't help. It could be a lot of simple things. Create a small side project that has the problem and post that.

madoodia

I got you, but it is not a minimal, because I don't know problem is because of opengl or not
btw the underlay sample in kdab repo is really minimal

underlay is using QQuickView as base class and use lib for Rendering, however we don't need to check the lib/meshrenderer
if we override any event in the QQuickView class it can not detect it and no action on it

I just added this to the header file

protected:
  void mousePressEvent(QMouseEvent *e) override;

and this to cpp file to check the event

void MyQuickView::mousePressEvent(QMouseEvent *e)
{
  //   qApp->sendEvent(mWindow, e);
  if (!e->isAccepted())
  {
    qDebug("Hello");
    QQuickView::mousePressEvent(e);
  }
}

and didn't touch the main.qml file

technically it should work because QQuickView class has virtual functions as events that is inherited from QWindow
https://doc.qt.io/qt-5/qquickview.html#reimplemented-protected-functions

make some sense?
thanks

fcarney

main.qml:

import QtQuick 2.12
import QtQuick.Window 2.12

import QuickTypes 1.0

MouseItem {
    visible: true
    width: 640
    height: 480
    title: qsTr("Mouse Item test")
}

main.cpp:

#include <QGuiApplication>
#include <QQmlApplicationEngine>

#include <mouseitem.h>

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

    QGuiApplication app(argc, argv);

    qmlRegisterType<MouseItem>("QuickTypes",1,0,"MouseItem");

    QQmlApplicationEngine engine;
    const QUrl url(QStringLiteral("qrc:/main.qml"));
    QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                     &app, [url](QObject *obj, const QUrl &objUrl) {
        if (!obj && url == objUrl)
            QCoreApplication::exit(-1);
    }, Qt::QueuedConnection);
    engine.load(url);

    return app.exec();
}

mouseitem.h:

#ifndef MOUSEITEM_H
#define MOUSEITEM_H

#include <QQuickView>

class MouseItem : public QQuickView
{
    Q_OBJECT
public:
    MouseItem();

protected:
    void mousePressEvent(QMouseEvent *e) override;

};

#endif // MOUSEITEM_H

mouseitem.cpp:

#include "mouseitem.h"

#include <QDebug>

MouseItem::MouseItem()
    : QQuickView()
{

}

void MouseItem::mousePressEvent(QMouseEvent *e)
{
  //   qApp->sendEvent(mWindow, e);
  qDebug() << "mousePressEvent";
  if (!e->isAccepted())
  {
    qDebug("Hello");
    QQuickView::mousePressEvent(e);
  }
}

I see the text "mousePressEvent", but I don't see the hello. So the events are happening.

fcarney

Is says here accepted is set true by default. I think if you dont want to accept the event you set it to false (setAccepted). If not you set to true? Not entirely sure.

madoodia

TBH, I did your method without !e->isAccepted() too, it didn't work
now it works now, even

void MouseItem::mousePressEvent(QMouseEvent *e)
{
  qDebug() << "mousePressEvent";
  qDebug("mousePressEvent");
}

don't understand
but there is another problem that it works, and print the message when click on the window, but it freezes the qml controllers
this is weird.
will test other events and will leave comment if there is any problem

madoodia

hey @fcarney
what if your MouseItem inherites from QQuickItem
and contain another QQuickWindow or QQuickView class in it, then register the Item?

you know what I mean?
A window inside an Item in qml

fcarney

freezes the qml controllers

It might be eating all the events. setAccepted to false will be like you didnt handle the event, I think.
Also, I don't know if you are supposed to embed an Windows in an Item.

madoodia

it does not reach to that point to check the setAccepted, it does not call mousePressEvent (or any other events) at all
when you use a Q*Window (object) inside a QQuickItem

How can we check this? that item will disable window events or not?
any idea?

madoodia

This is the more specific question about the mousePressEvent problem
https://forum.qt.io/topic/113640/why-q-window-events-are-eaten-by-qml-item

fcarney

Have you tried doing your opengl in a qtquickitem? I wonder if the problem is trying to embed a top level window inside a a qml item.

madoodia

I did, it works fine and show window contents (3D OpenGL) inside the Item, just I found we should enable mouse accepting, I'm still testing.
will update the post

thanks

madoodia

The problem is solved
please check this
https://forum.qt.io/topic/113640/solved-why-q-window-events-are-eaten-by-qml-item

thanks