qobject

问题 As the QObject documentation and many others explain, a QObject has an identity and thus hides its copy constructor and assignment operator. However, I'm not deriving from QObject for its dynamic properties feature or the signals/slots feature. I only want reflection , or the ability to access Foo::staticMetaObject . class Foo : public QObject { Q_OBJECT Q_ENUMS(Color) public: enum Color { Blue, Red, Pink }; private: Color color; }; Q_DECLARE_METATYPE(Foo::Color) I then can't copy Foo with:

问题 I wanted to know what is the best practice to connect signal/slots between two QObjects created in the contructor of MainWindow but moved to different threads later...default connections seems not working then when I connect with the option Qt::Directconnection things start working...but sometimes the signal/slot fails...following is my code pattern..please let me know if I need to change my class design... MainWindow.cpp MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), {

问题 I wanted to know what is the best practice to connect signal/slots between two QObjects created in the contructor of MainWindow but moved to different threads later...default connections seems not working then when I connect with the option Qt::Directconnection things start working...but sometimes the signal/slot fails...following is my code pattern..please let me know if I need to change my class design... MainWindow.cpp MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), {

问题 I am writing some Qt class which is derived from QObject , it looks like: class A : public QObject { Q_OBJECT public: A() : QObject() {} ..... } but in several places I saw, that the QObject derived classes all have a parent, like: class A : public QObject { Q_OBJECT public: A(QObject* parent = 0) : QObject(parent) {} ..... } So the question is: do I need a parent or not? What is the difference if I have one, if I have a default one (0) or I don't have at all? 回答1: As such you don't need a

问题 I am writing some Qt class which is derived from QObject , it looks like: class A : public QObject { Q_OBJECT public: A() : QObject() {} ..... } but in several places I saw, that the QObject derived classes all have a parent, like: class A : public QObject { Q_OBJECT public: A(QObject* parent = 0) : QObject(parent) {} ..... } So the question is: do I need a parent or not? What is the difference if I have one, if I have a default one (0) or I don't have at all? 回答1: As such you don't need a

问题 I have a situation where a QSharedPointer managed object signalizes that it has finished it's purpose and is ready for deletion soon (after execution left the function emitting my readyForDeletion signal). When working with normal pointers, I'd just call QObject::deleteLater on the object, however this isn't possible with a QSharedPointer -managed instance. My workaround is the following: template<typename T> class QSharedPointerContainer : public QObject { QSharedPointer<T> m_pSharedObj;

问题 I have a situation where a QSharedPointer managed object signalizes that it has finished it's purpose and is ready for deletion soon (after execution left the function emitting my readyForDeletion signal). When working with normal pointers, I'd just call QObject::deleteLater on the object, however this isn't possible with a QSharedPointer -managed instance. My workaround is the following: template<typename T> class QSharedPointerContainer : public QObject { QSharedPointer<T> m_pSharedObj;

问题 I have a custom class I created, say MyClass. Now how to add a reference to MyClass's reference as second parameter in the combo box below: this->ui->comboBox->addItem("item-1", ); Purpose is to when item changed even is fired, i want to get that specific class instance of MyClass and process accordingly. 回答1: First you need to use Q_DECLARE_METATYPE(MyClass*), so that the type can be used in QVariant . Then you can add the item like this: this->ui->comboBox->addItem("item-1", QVariant:

问题 Lets say I have a two classes: class A : public QObject {}; class B : public QObject {}; then I go QObject *a = new A(); QObject *b = new B(); now, how do I make sure that "a" is an instance of class A, and "b" is an instance of class B? currently I do something like this: if (a->inherits(A::staticMetaObject.className())) { ... } else if (a->inherits(A::staticMetaObject.className())) { ... is there a better way? 回答1: You can use qobject_cast<MyClass*>(instance) on QObject derived classes and

问题 I'm using Qt and have some real basic problems. I have created my own widget MyTest that have a variable obj . I need to set this variable obj from an object outside of the widget so that the variable is copied not just a pointer to another object. I get an error message and can't figure out how to do this basic stuff. This is the code I'm using: MyTest.h: class MyTest : public QWidget { Q_OBJECT public: void setObj(QObject &inobj); QObject obj; .... } MyTest.cpp: void MyTest::setObj(QObject