General and Desktop

@HerrWinfried The problem is that VS2022 doesn't return by default the right value for __cplusplus No idea if that's a bug or a feature in VS2022. However, here the solution how to overcome this issue: https://docs.microsoft.com/en-us/cpp/build/reference/zc-cplusplus?view=msvc-170 cheers Greg

@KroMignon said in Parsing JSON file: @jenya7 said in Parsing JSON file: It works. Thank you. But you did not reply to my question... What exactly did not work with your code? AFAIK, there is no difference between temperature.value("Maximum") and temperature["Maximum"]. Yes. It should be the same. Probably I didn't cast it to the right data type.

@django-Reinhard Fortunately I do not distribute any Qt apps, so I have never used them :) But if I did I would be looking at using linuxdeployqt and windeployqt.

@new-qt_user-2022 All the best! Feel free to post new questions if you'd like further help.

@themts Assuming you do write a separate Qt "VPN spawner" application, you then have a choice if it helps: you can start that startDetached(), or if you prefer for communication with it you can start it with normal start() and have it do the startDetached() when it starts the VPN process.

Use QComboBox::setItemData() with Qt::EditRole (or Qt::DisplayRole - it's the same for the underlying QStandardItemModel)

My bad, I was actually using QGraphicsView as a base. I've instead made a custom QGraphicsScene and I've overridden the mouse press event, like so: void CustomGraphicsScene::mousePressEvent(QGraphicsSceneMouseEvent *evt) { switch (evt->button()) { case Qt::LeftButton: { QList<QGraphicsItem *> items = this->items(evt->pos(), Qt::IntersectsItemBoundingRect); QListIterator<QGraphicsItem *> it(items); while (it.hasNext()) { QGraphicsItem *item = it.next(); if (item->boundingRegion(item->sceneTransform()) .contains(evt->pos().toPoint())) { item->setSelected(!item->isSelected()); break; // This can happen twice cuz of float rounding nonsense } } break; } case Qt::RightButton: { clearSelection(); break; } default: { break; } } QGraphicsScene::mousePressEvent(evt); } The reason I don't just use the graphics view mouse event is because, even though it was working before to an extent, it broke when I scrolled because the mouse event's position doesn't scroll with it. This doesn't work the same as that did, though, when it comes to selection of the whole item. Now I'm back where I started and am considering creating a rectangle around the point & getting the containing items of that & doing the boundingRect() logic myself. The code that somewhat worked before: void CustomGraphicsView::mousePressEvent(QMouseEvent *evt) { switch (evt->button()) { case Qt::LeftButton: { QList<QGraphicsItem *> items = this->scene()->items(evt->pos(), Qt::IntersectsItemBoundingRect); QListIterator<QGraphicsItem *> it(items); while (it.hasNext()) { QGraphicsItem *item = it.next(); if (item->boundingRegion(item->sceneTransform()).contains(evt->pos())) { item->setSelected(!item->isSelected()); break; // This can happen twice cuz of float rounding nonsense } } break; } case Qt::RightButton: { scene()->clearSelection(); break; } default: { break; } } QGraphicsView::mousePressEvent(evt); }

@kshegunov Heureka! You put me onto the right track: I found the following SQL working on SQLITE, solving my problem: SELECT productId , dateOfP , (SELECT sum(value) FROM (SELECT value FROM purchases AS pu WHERE pu.productId = purchases.productId AND pu.dateOfP > DATE(purchases.dateOfP, '-1 years') AND pu.dateOfP <= purchases.dateOfP) ) AS Summe FROM purchases GROUP BY dateOfP So thank you and also to Christian, who pointed into the right direction!

Hi That many labels are heavy to draw. A listView / Table with a delegate will be much faster. Look at https://forum.qt.io/topic/62363/custom-delegate/3 for starter code.

@Meeuxi said in How to create a QImage or QPixmap from raw pixel data (TGA): bytesPerLine You must know this since you created the raw image data CleanupFunction and *cleanupinfo. Since char* data need to stay alive until the whole lifetime of the QImage object (as stated in the documentation) you have two options a) create a QImage::copy() of the qimage so the bytes are copied b) make sure to delete the bytes when the image gets destroyed - this is what the cleanup function is for. So pass a function which cleans up your image data.

Hi @JonB, thanks for your reply. Ok, I'll try to look it up more before I ask here.

Why do you ask the same question every week (and deleting the old topic afterwards)? https://forum.qt.io/topic/133112/qdebug-compile-problem

Now it finally starts making sense. I was able to link the signals and slots together thanks to your explanation. I think the signal procedures are like radio transmitters that emit a message at a certain frequency. And a slot is the transmitter that must be tuned to the same frequency with connect() to be useful. But just like in radio, repeater receiver/transmitter pairs (chaining) are needed over long distances (across class boundaries). Please excuse my ramblings and many thanks for your helpful, clear explanations.

@Kent-Dorfman +1 for your command of the English language to (correctly) use "one fell swoop", and not the spelling so often found which refers to football or chickens... :) In a single word, is the way to achieve your desired behaviour by defining an eventFilter() on the dialog, where you can select which events to handle/pass on and which to ignore?

@Kill-Animals said in Do I need the private libraries in order to make a custom QGraphicsLayout?: do I need to be using the private libraries here No. They are private to the Qt library itself for a reason. The subclasses that already exist layout items in non-overlapping areas (horizontally, vertically, or both). It sounds like you want something far more complex than that. If you want to handle this as a layout manager then you really have no choice but to subclass QGraphicsLayout. When you do that your subclass needs to implement its own logic for all of the pure virtual members and develop its own mechanisms for actually laying out the contained items. It should not need to reach into the private workings of the abstract QGraphicsLayout to achieve this.

My mistake. If you note the second constructor does what I want: get a two dimensional array of [row ][column] that will allow me to construct a contiguous array of qreals. White the final constructor I was trying to make it less verbose. Some other languages allow something like x[0][:] to return and array with the first row of x[][]. Also, I will note that I have watching on but I do not get a notification unless I click no the icon, before a number, representing the number of notifications, would appear on the icon.

@JonB You are right. I will try.

@Publicnamer I look forward to your future illustration of such fundamental bugs in QString. The problem with programmers these days is that they do insist there are no bugs (without evidence), I don't agree with your sentiment here. Rather I find the problem with (some) programmers is that they are too quick to blame their tools --- toolkit, Qt, whatever --- when they should reflect on how widely used it is among other people and it is their own code they should examine instead. Speaking at least from experience on this forum I know just how many people come say "there is a bug in Qt" when their own code is faulty. Lots & lots of times....

@pingal That is a funny one! Windows should be case-insensitive, filename-wise. However, it looks like MinGW linker is case-sensitive to some degree.