signals-slots

问题 I've "Core" object that handles QMainWindow. Core.h code class Core : public QObject { Q_OBJECT public: explicit Core(QObject *parent = 0); ~Core(); void appInit(); int getAuth(); public slots: void appExit(); private slots: void appMenuTriggered(QAction *action); private: void preInit(); MainWindow *mwnd; }; Core.cpp code Core::Core(QObject *parent) : QObject(parent) { qDebug() << "Core::Constructor called"; preInit(); } Core::~Core() { delete mwnd; qDebug() << "Core::Destructor called"; }

问题 I have a pyside app that calls an exectuable. I want to run this executable asynchronously in n processes and capture the output of each process in a QTextEdit. At the moment I have: def run(self, args, worklist): self.viewer = OutputDialog(self) self.procs = [] for path in worklist: final_args = args + path p = QtCore.QProcess(self) p.readyReadStandardOutput.connect(self.write_process_output) self.procs.append(p) p.start(self.exe, final_args) def write_process_output(self): for p in self

问题 In my code I emit a signal (mySignal) and I want to wait for the end of a connected slot (mySlot) execution before it continues: emit mySignal(); // Wait for the end of mySlot execution... // Some code that has to be executed only after the end of mySlot execution... Is there a way to do so ? 回答1: If the sender and the receiver are in the same thread use Qt::DirectConnection , if they are in 2 different threads use Qt::BlockingQueuedConnection . ClassA a; ClassB b; ClassC c; c.moveToThread

问题 Setting up ray-caster I add QRayCaster to my root entity and connect its signal to a slot: void MySceneClass::createRootEntity() { // ... // Add ray caster to root entity m_rayCaster = new Qt3DRender::QRayCaster(m_rootEntity); m_rayCaster->setRunMode(Qt3DRender::QAbstractRayCaster::SingleShot); m_rootEntity->addComponent(m_rayCaster); // Set up signal to slot connection QObject::connect(m_rayCaster, &Qt3DRender::QRayCaster::hitsChanged, this, &MySceneClass::handleRayCasterHits); // ... } I

问题 I have a simple question guys, reading the thread about connecting signals with slots with fewer arguments, and of course, the Qt documentation. However, I do not need to connect signals with slots. I actually want to connect signals with signals with fewer arguments . The documentation is very clear about slots, but what about signals? Is that considered safe? Thanks & Cheers! 回答1: There is no difference. The receiving signal may have a shorter signature than the emitting signal. because it

问题 I was browsing the methods inside of QMainWindow and noticed that some parts (such as resizeEvent and winEvent) are not implemented as signals but rather you have to inherit this class to be able to override them. My question is, how efficient are signals and slots and would it be possible to implement these types of functions as signals from which other classes can subscribe to. For instance, inside of a high performance game engine. 回答1: From what I recall, Trolltech stated that a signal

问题 So for the only way that I can see to create a style signal with PyQt4 is as follows: class MyCustomClass(QtCore.QThread): custom_signal = QtCore.pyqtSignal(str) My beef is if I declare that signal anywhere else, pyqt throws an error at me about how custom_signal doesn't have a connect() function. I would like to create a helper function to help remove the boilerplate/repeated code when I want to do something as simple as: starting a new thread, doing work in that thread, sending the result

问题 So for the only way that I can see to create a style signal with PyQt4 is as follows: class MyCustomClass(QtCore.QThread): custom_signal = QtCore.pyqtSignal(str) My beef is if I declare that signal anywhere else, pyqt throws an error at me about how custom_signal doesn't have a connect() function. I would like to create a helper function to help remove the boilerplate/repeated code when I want to do something as simple as: starting a new thread, doing work in that thread, sending the result

问题 I am learning Qt framework (C++) and was wondering if QT has any mechanisms to protect slots from being called before an object is fully initialized. Consider Class A constructor: A::A() { mTreeView = new QTreeView(); ... connect(mTreeView, &QTreeView::customContextMenuRequested, this, &A::OnContextMenuRequested); ... } My worry is the user would be able to right-click on the tree-view before A's constructor has finished. Another context is as follows: A::A() { mQObj = new MyQObject();

问题 In the Qt document it is said: if several slots are connected to one signal, the slots will be executed one after the other, in the order they have been connected, when the signal is emitted. But in the connect() function, setting the Qt::ConnectionType type as Qt::QueuedConnection means "The slot is invoked when control returns to the event loop of the receiver's thread. The slot is executed in the receiver's thread." and Qt::DirectConnection means "the slot is invoked immediately, when the