I'm learning and messing around in Qt with Widget application and I made some QPushButtons that do some straight forward actions, but as you would expect only when you click them with mouse, how can you make it work that way, that a specific keyboard press event does that same work as clicking that button? I couldn't get much from online tutorials as I don't even know how to specify what am I looking for. Thanks
use QShortcut or create derived class from QPushButton and re-implement QKeyPressEvent method
Related
In order to create a QComboBox that can filter its values list when typing in it, I attached a slot to the QComboBox's editTextChanged-event, to open its list view popup when the user starts typing. This is done like so:
void SearchableComboBox::slotEditing(QString in_text)
{
this->showPopup();
}
Unfortunately, this immediatly steals the focus from the QLineEdit and I can't type anymore.
Calling lineEdit()->setFocus() makes no difference, and I don't want to grabKeyboard() since this creates a whole other world of pain.
Any recommendations?
This isn't really a combobox then, more of a completion listview for a lineedit. I implemented exactly that in ruqola (KDE client for rocket chat), you can see the source code at https://lxr.kde.org/source/network/ruqola/src/widgets/common/completionlistview.cpp. Notice the little dance with the focus proxy thing:
setFocusPolicy(Qt::NoFocus);
textWidget->setFocusPolicy(origPolicy);
setFocusProxy(textWidget);
and the long method slotCompletionAvailable() for positioning the completion popup at the right place...
Use the Focus Proxy method for this purpose. See https://doc.qt.io/qt-5/qwidget.html#setFocusProxy
With this the pop-up would relay its inputs to the lineedit.
In your case you could try something like
this->setFocusProxy( this->lineEdit() );
But maybe you should read how to use a QCompleter. This would provide Autocompletion while typing and is maybe also useful for you.
I couldn't find an answer to this so here goes nothing:
I'm developing a GUI for an embedded Linux and it needs to be able to push 2 buttons and do different functions when one of the 2 is already pushed (like a shiftbutton on your keyboard). I tried using button->setAutoRepeat(true);
It does what it says but it doesn't allow other buttons to be pressed at the same time. The embedded Linux system has a 10-finger touchscreen so it should allow multiple buttons at the same time.
TL;DR: I can't find a way to press another button while a button is already pressed.
Solution 1:
Use QAbstractButton::isDown() to check if the shift like button is down when processing event in the action button.
Solution 2:
QAbstractButton hsd setChecked/isChecked functions which can be useful.
Solution 3:
Subclass the QPushButton and reimplement keyPressEvent or you can install event filter for your button and process QMouseEvent. This solution will give you more flexibility in your code.
Choose one of it depending on usage and requirement.
Working with wxWidgets on W7, with focus over a wxButton, I would like to avoid button activation pressing SPACE or ENTER keys.
The button should reacts only on click events.
What is the right way to do it?
Thanks
You should be able to do this by catching EVT_KEY_DOWN event and doing nothing in your handler, but I'd strongly recommend not doing this. Users expect these keys to work with the buttons and if you want something that doesn't react to the keyboard, you should use some other (custom) control and not wxButton at all.
I have 3 buttons on QMessageBox added by QMessageBox::addButton() method. Is it possible to prevent closing the message box if a button has been clicked? By default every button closes the window, but I don't want to do it for one button.
One interesting way to approach it that worked for me is to completely disconnect the signals for the target button created, and then re-add the intended functionality. This won't work for everyone, especially if the button isn't created this way and/or you still want to close the dialog correctly. (There might be a way to add it back and/or simulate the behavior with QDialog::accept, QDialog::reject, QDialog::done - haven't tried yet.)
Example:
QMessageBox *msgBox = new QMessageBox(this);
QAbstractButton *doNotCloseButton = msgBox->addButton(tr("This button will not close anything"), QMessageBox::ActionRole);
// Disconnect all events - this will prevent the button from closing the dialog
doNotCloseButton->disconnect();
connect(doNotCloseButton, &QAbstractButton::clicked, this, [=](){ doNotCloseButton->setText("See? Still open!"); });
If you can get a pointer to the QMessageBox widget, you can try to install a QObject::eventFilter on it which filters the QEvent::Close.
Just had the same problem but I wanted to add a checkbox and it kept closing the dialog on clicked even with the ButtonRole set to QMessageBox::ActionRole (tried others too). For this scenario I just called blockSignals(true) on the QCheckBox and now it allows check/uncheck behaviour without closing the dialog. Luckily QCheckBox works fine without signals but assume you want a signal from your button.
They should likely add a new role that doesn't close the dialog as it's a pain to derive a class for simple customizations.
I looked through the addButton() functions overloads, but there is no custom behavior for the buttons you add with this method. They will behave like the standard buttons on a messagebox should.
However if you want to create a fully customizable dialog, then your best option is to extend the QDialog class and use whatever controlls you like on it.
Thanks to #Albert's Answer, I found that this also possible in python:
messagebox = QMessageBox()
button = QPushButton("This button will not close anything")
messagebox.addButton(button, QMessageBox.ButtonRole.NoRole)
button.disconnect()
I'm using the Qt library to show a slideshow on the second monitor when the user isn't using the second monitor. An example is the user playing a game in the first monitor and showing the slideshow in the second monitor.
The problem is that when I open a new window in Qt, it automatically steals the focus from the previous application. Is there any way to prevent this from happening?
It took me a while to find it but I found it: setAttribute(Qt::WA_ShowWithoutActivating);
This forces the window not to activate. Even with the Qt::WindowStaysOnTopHint flag
If you want to make floating preview box/ any other widget just use below
thumbnail = new QLabel;
thumbnail->setAttribute(Qt::WA_ShowWithoutActivating);
thumbnail->setParent(0);
thumbnail->setWindowFlags(Qt::Tool | Qt::FramelessWindowHint|Qt::WindowStaysOnTopHint);
Qt::Tool is important flag to make it work. I mean not stealing focus.
Widgets don't accept focus by default but presumably you haven't created a plain widget? Which subclass was it? QMainWindow or something else?
It's possible the window subclasses default to accepting focus so try explicitly calling QWidget::setFocusPolicy with Qt::NoFocus before calling QWidget::show().
Also, make sure you're not calling QWidget::activateWindow() on the window or any of its widgets at any point.