I have a QT App and have currently added a new QPushButton.
I have connected the button properly with:
QObject::connect(ui->myButton, SIGNAL(clicked()), this, SLOT(SendResetEchoRequest()));
Most of the time it is working when i click it calls the function. But sometimes it doesn't register my click. Sometimes i need up to 5-10 clicks to make the function fire once and i don't know why.
To be sure this is a problem with the Button / Click i have tried using the function on key UP like this:
if(GetAsyncKeyState(VK_UP)){
SendResetEchoRequest();
}
This works 100% perfectly fine. And when i press my UP key it triggers the function.
Anybody got an idea why sometimes it doesn't register my click?
I am not sure if it will be of any help, I would like to suggest a quick exercise to examine.
You can connect to the signals pressed and released and in the slot routine try to set the button text to "Pressed"and on button release it should go back to "<your button text>"
QObject::connect(ui->myButton, SIGNAL(pressed()), this, SLOT(setbuttonPressed()));
QObject::connect(ui->myButton, SIGNAL(released()), this, SLOT(setbuttonReleased()));
setbuttonPressed() {
ui->myButton->setText("Pressed"); }
setbuttonReleased() {
ui->myButton->setText("My Button"); }
This way when you see that occasional problem you can examine if QAbstractButton or QPushButton class ever signals anything. This is just my thought to debug what's going on, may not be the solution to your problem.
Related
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
I am writing a simple GUI, in which I have a ComboBoxText. I write a log message when ever the user clicks on the ComboBoxText.
I have tried almost all the button release and popup signals but no results. The only thing which works is signal_changed() but I don't not need that. Please help me, below is my sample code :
myCombo->signal_button_release_event().connect(sigc::mem_fun(this,&ComboBoxText::ComboInput),false);
and here is the call back function:
bool ComboBoxText::ComboInput(GdkEventButton *pEvt) {
// Here do the desired stuffs !!
return false; }
Use GTK+ property popup-shown. Not sure about Gtkmm syntax, probably property_popup_shown().get_value().
If you need a signal to listen to, connect to popdown or notify::popup-shown (the latter is invoked when property value changes; again, I'm not sure about Gtkmm syntax).
The idea here was to fire an event when the ComboBoxText is clicked. After some readings I figured it out that the ComboBoxText does not fire any on_click event as such.
One could mask a key press event (which by the way gets fired) and call the signal handler. This might not be handy for people who specifically looking for a on_click event but for those who are working with a keyboard or touch screen device. Here is a small chunk of code :`
mCombo.add_events(Gdk::KEY_PRESS_MASK);
mCombo.signal_event().connect(sigc::mem_fun(this,&ClassName::Handler),false);
cheers :)
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()
In my QMenuBar, I have several menus.
One of those menus has a QWidgetAction in it.
It shows up fine, but the problem is that once the user completes his input, I want the menu to disappear (as is the normal behavior for a classical QAction).
However, I am not sure on how to do that. In my QWidgetAction, there is a button the user presses when he is done; I can therefore bind to this button's clicked() signal.
In the slot, I tried to setFocus() an element outside the menu but the menu still doesn't disappear.
How to tell the menu to close itself when my users finish interacting with the QWidgetAction?
Thanks
QMenu inherits QWidget, so calling yourMenu->hide() should do the work.
Hope this helps.
I just started using QtCreator tonight, and it seems it puts all of the interface stuff inside of the ui file. I followed a tutorial to create a resource for my icons, then I added them to a menu bar at the top.
I need to make a connection when one of them is clicked though, and cannot figure out how to make a callback for it.
Am I going to have to completely create them through code or is there some way to add a callback for them (rather than just making them interact with other objects).
Menu bar items are action objects. To do something when they are clicked, you need to catch the triggered() signal from the action. Read more about signals and slots here.
To do this, you need to declare a new slot in your MainWindow class. Qt also supports doing this automatically, without the need to connect anything, but I prefer doing it myself. If you're not interested, just skip this part.
First, we declare a new slot in your window class:
private slots:
void clickMenuButton();
Then, in your constructor, you need to connect the triggered signal to your new slot:
connect(ui.actionObject, SIGNAL(triggered()), this, SLOT(clickMenuButton()));
The first argument is the object that holds the signal we'll listen to (your menu button). The second is the name of the signal. The third is the object that holds the receiving slot (in this case, our window). The fourth is the slot.
And just like that, clickMenuButton() will be called whenever the action is clicked.
As I said before, Qt can also automatically connect signals to slots. The disadvantage here seems to be that you can't change the slot's name, but you don't need to connect it either.
Qt Creator supports creation of slots for widgets: in the case of your menu action, you should go to the form designer, and you should see a list of actions in your form (if you don't, find the Action Editor). Right click the action you want, and push Go to slot.... There, double click triggered().
Qt Creator will then open the new slot in your code editor, and you can do whatever you want to here!
To do that you'll need to add a QAction, add it to the menu, associate an icon with it and then create a callback for it. I'm using the VS Integration so I don't know the details of how to do it in Creator but it should be possible without creating stuff in code.
There should be somewhere an actions editor. from there you add an action, then right-click it or something to add an icon to it, then drag it do the menu and then possibly double click it to create a slot for it. This is how it works in the VS Integration atleast.