mouseRelease doesn't work

[A Former User]

I used pressEvent and moueseReleaseEvent for dragging and resize mainwindow in an other screen, beacuse I have 2 screens I wrote in .h

protected:
    void mousePressEvent(QMouseEvent * event);
    void mouseReleaseEvent(QMouseEvent * event);

in .cpp.

void MainWindow::mousePressEvent(QMouseEvent *event)
{
    qDebug() << "Pressed";
}

void MainWindow::mouseReleaseEvent(QMouseEvent *event)
{
    qDebug() << "Released";
}

I click on the titlebar ...I don't know if it's the why...I want only to move my mainWindow in the other screen and do the resize when I release the mouse

[A Former User]

@vale88 the event released isn't registered

[mrjj]

Hi
Clicking on the title bar of a Window is NOT handled by Qt.
Its the operating system.

You can use native code to detect it.
Like

#include "windows.h"
#include "windowsx.h"
protected:
    bool nativeEvent(const QByteArray &eventType, void *message, long *result) override
    {
        MSG *msg = (MSG *)(message);
        if (msg->message == WM_NCLBUTTONDOWN) {

            int mouseX = GET_X_LPARAM(msg->lParam);
            int mouseY = GET_Y_LPARAM(msg->lParam);
            QRect frame = frameGeometry();
            QRect content = geometry();

            qDebug() << "mouseX: " << mouseX << "mouseY:" << mouseY;
            qDebug() << "frame: " << frame;
            qDebug() << "content: " << content;

            if (mouseY < content.y() && mouseY >= frame.y()) {
                qDebug() << "Hit title bar";
            }
        }

        *result = 0;
        return false;
    }

however this ONLY works on Windows.

[A Former User]

@mrjj I use press and release to move the mainWindow, but I don't understand, I must write your code and use press event and release event like I did before?

[mrjj]

@vale88
Hi
The code is for detecting clicking on the titlebar.
It will not work with press event and release event like normally.

we test here for WM_NCLBUTTONDOWN
and you can also test for WM_NCLBUTTONUP

[A Former User]

@mrjj ok, so I can't see with this when I drag the mainWindow, is there an othere way?
Son I an't see when I release the mouse?

[mrjj]

@vale88
well to your mainwindow you can override
virtual void moveEvent ( QMoveEvent * event )
then you are told when window is moved.

-Son I an't see when I release the mouse?
Not on the titlebar. only inside thw window.

[A Former User]

@mrjj Yes I used moveEvent, in fact, to drag mainWindow and resize mainWindow in the second screen, but if I resize while I move, so with moveEvent, I have problems, I need an event which can permit me to understand when I released the mouse and mainWindow is in the other screen, becuse I use showMaximized

[mrjj]

@vale88
well WM_NCLBUTTONUP would be send when you release mouse on
the title bar, if that is enough?
You can then check which screen you are on.

[A Former User]

@mrjj but this event works when I click on title bar, right?so it's like pressEvent, and when release the mouse, how Can i use it?

[mrjj]

@vale88
something like

bool nativeEvent(const QByteArray &eventType, void *message, long *result) 
{
    MSG *msg = (MSG *)(message);
    if (msg->message == WM_NCLBUTTONDOWN || msg->message == WM_NCLBUTTONUP) {
        int mouseX = GET_X_LPARAM(msg->lParam);
        int mouseY = GET_Y_LPARAM(msg->lParam);
        QRect frame = frameGeometry();
        QRect content = geometry();
        if (mouseY < content.y() && mouseY >= frame.y()) {
            if ( msg->message == WM_NCLBUTTONDOWN )  {
                // ON CLICK
            }  else {
                // ON RELEASE
            }
        }
    }

    *result = 0;
    return false;
}

[A Former User]

@mrjj Ok thanks, tomorrow I try, if there is an other way to resize the mainWindow when it's in an other screen, please tell me it, thanks

[A Former User]

@mrjj I have an error in frameGeometry and geometry, qt said that isn't declared

[A Former User]

@mrjj I tried you code but it works only on click and not when I release

[mrjj]

well there was a typo
if (WM_NCLBUTTONDOWN ) {
should have been
if (msg->message == WM_NCLBUTTONDOWN ) {

so it would always say it was clicked.

Update:
You are right - it's not sending the WM_NCLBUTTONUP
I assume left click starts a drag, and no UP event will be seen since windows then do a mouse capture.

So sorry. forget they code. it cannot work for what you want since you will never get the UP event.