This is my class declaration:
class Browser : public QWidget {
Q_OBJECT
public:
Browser(QWidget *parent = 0);
QStringList loadSettings(QString settings_file);
private slots:
void toggleFullscreen();
private:
void createActions();
QAction *aToggleFullscreen;
};
And relevand definitions:
void Browser::toggleFullscreen() {
out << "fullscreen!" << endl;
}
void Browser::createActions() {
aToggleFullscreen = new QAction(this);
aToggleFullscreen->setShortcut(tr("F11"));
connect(aToggleFullscreen, SIGNAL(triggered()), this, SLOT(toggleFullscreen()));
}
I'm calling createActions() from Browser::Browser.
I have no runtime warning that slot doesn't exists, etc. But still nothing is triggered if I hit F11.
I tried also:
aToggleFullscreen->setShortcut(QString("F11"));
What is it wrong with my code?
You forgot to actually add your action to the Browser, so it never gets triggered. This should work:
void Browser::createActions() {
aToggleFullscreen = new QAction(this);
aToggleFullscreen->setShortcut(tr("F11"));
connect(aToggleFullscreen, SIGNAL(triggered()), this, SLOT(toggleFullscreen()));
addAction(aToggleFullscreen);
}
Related
In Class Buttons, I have a btnRightClicked signal and a mousePressEvent slot:
void Buttons::mousePressEvent(QMouseEvent *e)
{
if(e->button() == Qt::RightButton) {
emit btnRightClicked();
}
}
And in mainwindow.cpp, I connect the btnRightClicked signal to onRightClicked slot like this:
connect(&mButtons, SIGNAL(btnRightClicked()), this, SLOT(onRightClicked()));
The onRightClicked slot is like this:
void MainWindow::onRightClicked()
{
qDebug() << "right clicked";
}
But I ran this program, nothing happened. I guess the reason is because I did not connect to the mousePressEvent slot. I am kind of new to Qt, I do not know if I am right or not.
I set up some buttons on the central widget, I want them to have the right clicked event when right click each of them. So how can I make this work?Thanks
Edit:
in button.h:
class Buttons : public QObject
{
Q_OBJECT
public:
Buttons();
QVector<QPushButton*> buttons;
void setButtons(int totalBtns) {
for(int i = 0; i < totalBtns; i++) {
buttons[i]->setObjectName(QString::number(i));
buttons[i]->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
}
}
public slots:
void mousePressEvent(QMouseEvent *e) {
if(e->button() == Qt::RightButton) {
emit btnRightClicked();
}
}
signals:
void btnRightClicked();
};
To get the mouse right click on your widget, you need to implement your own button widget.
class MyButton : public QPushButton
{
Q_OBJECT
public:
MyButton(QWidget *parent = Q_NULLPTR);
private slots:
void mousePressEvent(QMouseEvent *e);
signals:
void btnRightClicked();
};
cpp
MyButton:MyButton(QWidget * parent) :
QPushButton(parent)
{
}
void MyButton::mousePressEvent(QMouseEvent *e)
{
if(e->button()==Qt::RightButton)
emit btnRightClicked();
//this forwards the event to the QPushButton
QPushButton::mousePressEvent(e);
}
In your buttons class change the button vector to
QVector<MyButton*> buttons;
Then register the right click event of your MyButton to your signal in Buttons class then forwared the signal to your mainWindow
connect(&mButtons, &Buttons::btnRightClicked,
this, &MainWindow::onRightClicked);
I'm developing a multithreaded application, I need to instantiate n devices by modbus.
So I created a controller (ServiceSM) that instantiates N threads (ServiceSlots).
The devices are varied so I had to create "drivers" for each type of device, one of the drivers uses the QModbusClient class, so I created a controller to manage the device type.
schema
To test the operation of the state machine and connection to the device, I made an example code to run in a graphical interface.
I deleted some snippets of code that do not matter to make it easier to understand
In the MD4040driver class
When my code runs this section, the following messages appear.
If I instantiate the DeviceDriver class in the graphical interface, it works perfectly, the problem occurs when I instantiate it inside a thread.
when calls
modbusDevice->connectDevice()
MD4040drive::sm_conn() - try connect - this my message
Error:
QObject::connect: Cannot queue arguments of type
'QModbusDevice::State' (Make sure 'QModbusDevice::State' is registered
using qRegisterMetaType().)
QObject: Cannot create children for a parent that is in a different
thread. (Parent is QTcpSocket(0x24a6ce8), parent's thread is
ServiceSlots(0xea66488), current thread is QThread(0x2418a78)
QObject: Cannot create children for a parent that is in a different
thread. (Parent is QTcpSocket(0x24a6ce8), parent's thread is
ServiceSlots(0xea66488), current thread is QThread(0x2418a78)
void MD4040drive::sm_conn()
{
if (modbusDevice->state() != QModbusDevice::ConnectedState) {
modbusDevice->setConnectionParameter(QModbusDevice::NetworkPortParameter, this->cfg.modbus.porta );
modbusDevice->setConnectionParameter(QModbusDevice::NetworkAddressParameter, this->cfg.modbus.ip);
modbusDevice->setTimeout( this->cfg.modbus.timeout );
modbusDevice->setNumberOfRetries(this->cfg.modbus.retries);
qDebug() << "MD4040drive::sm_conn() - try connect";
if (!modbusDevice->connectDevice()) {
qDebug() << "Erro: " << modbusDevice->errorString();
} else {
qDebug() << "Aguardando conexão...";
}
}
else{
//already connected...
this->getDados_NO_TH();
}
}
rest my code(parts)
devicedriverviewgui.h
devicedriverviewgui.cpp
class DeviceDriverViewGUI : public QDialog
{
Q_OBJECT
public:
explicit DeviceDriverViewGUI(QWidget *parent = 0);
~DeviceDriverViewGUI();
private slots:
void on_pbTry_clicked();
private:
Ui::DeviceDriverViewGUI *ui;
ServiceSlots *serviceSlot;
};
void DeviceDriverViewGUI::on_pbTry_clicked()
{
Equip equip_try = Equip();
serviceSlot = new ServiceSlots();
serviceSlot->setEquipamento(equip_try);
serviceSlot->start();
}
serviceslots.h
serviceslots.cpp
class ServiceSlots : public QThread
{
Q_OBJECT
public:
ServiceSlots();
void run();
private:
QTimer *timer;
DeviceDriver *device;
private slots:
void sm_getData();
void device_response(bool boEnd);
};
void ServiceSlots::run()
{
int e;
eventLoop = new QEventLoop();
timer = new QTimer();
connect(timer, SIGNAL(timeout()),this, SLOT(sm_controler()));
timer->start(TICK_SM_SLOT);
this->device = new DeviceDriver();
e = eventLoop->exec();
qDebug() << "Exit loop"<< e;
}
void ServiceSlots::sm_controler()
{
if(this->idleState){;}
else{
this->sm_getData();
this->idleState = true;
}
}
void ServiceSlots::sm_getData()
{
connect(device,SIGNAL(end(bool)),this,SLOT(device_response(bool)));
device->requestDeviceDriver(&this->equipamento,&this->next_date);
}
devicedriver.h
devicedriver.cpp
class DeviceDriver : public QObject
{
Q_OBJECT
public:
DeviceDriver();
void requestDeviceDriver(Equip *equip,QDateTime *date);
private:
//Drivers de dispositivos..
MD4040drive *md4040;
private slots:
//Request data to driver...
void request();
signals:
void end(bool boEnd);
};
void DeviceDriver::request()
{
connect(md4040,SIGNAL(end(bool)),this,SLOT(md4040_end(bool)));
this->md4040->requestMD4040drive(&this->equip,&this->date);
}
DeviceDriver::DeviceDriver(){
----
md4040 = new MD4040drive();
---
}
void DeviceDriver::requestDeviceDriver(Equip *equip, QDateTime *date){
this->equip = *equip;
this->date = *date;
this->request();
}
md4040drive.h
md4040drive.cpp
class MD4040drive : public QObject // QObject//public QObject QRunnable QThread
{
Q_OBJECT
public:
explicit MD4040drive(QObject *parent = 0);
~MD4040drive();
void requestMD4040drive(Equip *equip,QDateTime *date);
private:
void run();
QModbusClient *modbusDevice;
private slots:
void m_conn();
signals:
void end(bool boRun);
};
MD4040drive::MD4040drive(QObject *parent): QObject(parent)
{
modbusDevice = new QModbusTcpClient();
connect(modbusDevice, &QModbusClient::stateChanged,this, &MD4040drive::onStateChanged);
}
void MD4040drive::requestMD4040drive(Equip *equip, QDateTime *date)
{
this->equip = *equip;
this->date = *date;
this->run();
}
void MD4040drive::run()
{
this->sm_conn();
}
void MD4040drive::sm_conn()
{
if (modbusDevice->state() != QModbusDevice::ConnectedState) {
modbusDevice->setConnectionParameter(QModbusDevice::NetworkPortParameter, this->cfg.modbus.porta );
modbusDevice->setConnectionParameter(QModbusDevice::NetworkAddressParameter, this->cfg.modbus.ip);
modbusDevice->setTimeout( this->cfg.modbus.timeout );
modbusDevice->setNumberOfRetries(this->cfg.modbus.retries);
qDebug() << "MD4040drive::sm_conn() - try connect";
if (!modbusDevice->connectDevice()) {
qDebug() << "Erro: " << modbusDevice->errorString();
} else {
qDebug() << "Aguardando conexão...";
}
}
else{
//already connected...
this->getDados_NO_TH();
}
}
There are a few problems:
You need to call qRegisterMetaType<QModbusDevice::State>() in main().
You need to maintain parent-child relationships between all objects that are potentially moved to other threads as a group.
The ServiceSlots and DeviceDriver classes seem to be unnecessary.
The ubiquitous this-> is non-idiomatic C++. Don't write this-> unless you need to disambiguate a member from a local variable.
Prefer to hold objects by value if they have the same lifetime as the parent object. Let the compiler generate memory management code for you!
Leverage C++11.
Fist of all, let's have a helper SafeThread class that provides us with a thread that is safely destructible at any time:
class SafeThread : public QThread {
Q_OBJECT
using QThread::run;
public:
using QThread::QThread;
~SafeThread() { quit(); wait(); }
};
The DeviceDriverViewGUI class can hold the drive and its thread by value:
class DeviceDriverViewGUI : public QDialog
{
Q_OBJECT
public:
explicit DeviceDriverViewGUI(QWidget *parent = nullptr);
private:
Ui::DeviceDriverViewGUI ui;
MD4040drive drive;
SafeThread driveThread{this};
Equip equipamento;
QDateTime nextDate;
Q_SLOT void on_pbTry_clicked();
};
Then, the pushbutton can be connected directly to the drive's thread context, and run the requestMD4040drive in the proper thread:
DeviceDriverViewGUI::DeviceDriverViewGUI(QWidget *parent) : QDialog(parent)
{
ui.setupUi(this);
// vvvvvv -- gives the thread context
connect(ui.pbTry, &QPushButton::clicked, &drive, [this]{
Q_ASSERT(QThread::currentThread() == drive.thread()); // ensured by the thread context
drive.requestMD4040drive(&equipamento, nextDate);
});
connect(&drive, &MD4040drive::end, this, [this](bool end){
//...
});
drive.moveToThread(&driveThread);
driveThread.start();
}
When done this way, you don't need any extraneous helper objects nor timers to queue requests. Qt handles all of it.
When passing Qt value classes to functions, pass them by const reference, not by pointer. The MD4040drive should look roughly as follows:
class MD4040drive : public QObject
{
Q_OBJECT
public:
explicit MD4040drive(QObject *parent = nullptr);
void requestMD4040drive(Equip *equip, const QDateTime &date);
Q_SIGNAL void end(bool boRun);
private:
Equip *equip = nullptr;
QDateTime date;
QModbusTcpClient modbusDevice{this};
Cfg cfg;
Q_SLOT void onStateChanged();
Q_SLOT void m_conn();
void sm_conn();
void getDados_NO_TH() {}
};
The implementation:
MD4040drive::MD4040drive(QObject *parent): QObject(parent)
{
connect(&modbusDevice, &QModbusClient::stateChanged,this, &MD4040drive::onStateChanged);
}
void MD4040drive::requestMD4040drive(Equip *equip, const QDateTime &date)
{
this->equip = equip;
this->date = date;
sm_conn();
}
void MD4040drive::sm_conn()
{
if (modbusDevice.state() != QModbusDevice::ConnectedState) {
modbusDevice.setConnectionParameter(QModbusDevice::NetworkPortParameter, cfg.modbus.porta );
modbusDevice.setConnectionParameter(QModbusDevice::NetworkAddressParameter, cfg.modbus.ip);
modbusDevice.setTimeout( this->cfg.modbus.timeout );
modbusDevice.setNumberOfRetries(this->cfg.modbus.retries);
qDebug() << "MD4040drive::sm_conn() - try connect";
if (!modbusDevice.connectDevice()) {
qDebug() << "Erro: " << modbusDevice.errorString();
} else {
qDebug() << "Aguardando conexão...";
}
}
else{
//already connected...
getDados_NO_TH();
}
}
The configuration class might look as follows - notice that the compiler will generate the necessary constructors and destructors for you:
struct Cfg {
struct Modbus {
int porta = 0;
QString ip = QStringLiteral("127.0.0.1");
int timeout = 1000;
int retries = 2;
} modbus;
};
Make sure 'QModbusDevice::State' is registered using qRegisterMetaType()
Means you need to call qRegisterMetaType<QModbusDevice::State>(); before connecting signal/slot that would pass this type of parameter between threads.
And/or add Q_DECLARE_METATYPE(QModbusDevice::State) macro at global scope (never understood clearly which one is actually needed, putting both works for sure...).
See this post for more details: Emitting signals with custom types does not work
I have the following code that works as expected. It updates the progress bar value in each for loop. The only issue I have is when I'm done and call emit ProcessUserRowsFinished() in the method OnProcessUserRowsStarted the program crashes.
class UsersProcess: public QObject
{
Q_OBJECT
public:
UsersProcess(CTCore::DBConnect* db_context, UserSettingsMap user_settings_map);
void SetProgressBar(QProgressBar *progress_bar);
private:
QProgressBar *progressBar;
QSharedPointer<QList<CTCoreZen::User>> listUsers;
QScopedPointer<QThread> threadRowWorker;
signals:
void ProcessUserRowsFinished();
void ProgressBarSetValue(int value);
}
void UsersProcess::SetProgressBar(QProgressBar *progress_bar)
{
this->progressBar = progress_bar;
}
void UsersProcess::OnUserListSuccess(QList<CTCoreZen::User> *users)
{
this->listUsers.reset(users);
this->progressBar->setVisible(true);
this->progressBar->setTextVisible(true);
this->progressBar->setMinimum(0);
this->progressBar->setMaximum(this->listUsers->size());
this->progressBar->setValue(0);
this->threadRowWorker.reset(new QThread());
this->moveToThread(this->threadRowWorker.data());
connect(this->threadRowWorker.data(), &QThread::started, this, &UsersProcess::OnProcessUserRowsStarted);
connect(this, &UsersProcess::ProgressBarSetValue, this->progressBar, &QProgressBar::setValue);
connect(this, &UsersProcess::ProcessUserRowsFinished, this->threadRowWorker.data(), &QThread::quit);
connect(this, &UsersProcess::ProcessUserRowsFinished, this, &UsersProcess::deleteLater);
connect(this->threadRowWorker.data(), &QThread::finished, this->threadRowWorker.data(), &QThread::deleteLater);
this->threadRowWorker->start();
}
void UsersProcess::OnProcessUserRowsStarted()
{
int row = 0;
UsersData userData(this->dbContext);
int maxRows = this->listUsers->size();
for(auto iter = this->listUsers->begin(); iter != this->listUsers->end(); ++iter)
{
row++;
emit this->ProgressBarSetValue(row);
}
emit ProcessUserRowsFinished();
}
This is because of your thread has been deleted.
This call deletes the instance of class UsersProcess and QScopedPointer deletes the thread.
connect(this, &UsersProcess::ProcessUserRowsFinished, this, &UsersProcess::deleteLater);
But you also have this connections
connect(this, &UsersProcess::ProcessUserRowsFinished, this->threadRowWorker.data(), &QThread::quit);
connect(this->threadRowWorker.data(), &QThread::finished, this->threadRowWorker.data(), &QThread::deleteLater);
When one of this events fires the thread is already deleted.
I got this Error Message when I compile my project:
"Can not convert 'Principal::setValues' from type 'void*(Principal::)(void*)' to type 'void*()(void)' "
...
enter code here
void* Principal:: setValues(void*){
QString velocidadCARGA=QString::number(VelocidadCargador);
QString velocidadLAVA=QString::number(VelocidadLavado);
ui->Velocidad_Carga->setText(velocidadCARGA);
ui->Velocidad_Lavado->setText(velocidadLAVA);
ui->lbl_CantidadActual_Banda_Principal->setNum(botellasCargadas);
return NULL;
}
void Principal::on_Start_Cargador_clicked(){
pthread_t hilo3;
pthread_create(&hilo3,NULL,setValues,NULL);//error in this line.
pthread_join(hilo3,NULL);
}
Principal::setValues is a member function, so its type does not conform with a function type required by pthread_create.
To launch a member function in a thread you can declare some static method and pass this object into it:
class Principal
{
...
static void* setValuesThread(void *data);
...
}
void* Principal::setValuesThread(void *data)
{
Principal *self = reinterpret_cast<Principal*>(data);
self->setValues();
return NULL;
}
// your code
void Principal::setValues()
{
QString velocidadCARGA=QString::number(VelocidadCargador);
QString velocidadLAVA=QString::number(VelocidadLavado);
ui->Velocidad_Carga->setText(velocidadCARGA);
ui->Velocidad_Lavado->setText(velocidadLAVA);
ui->lbl_CantidadActual_Banda_Principal->setNum(botellasCargadas);
}
void Principal::on_Start_Cargador_clicked()
{
pthread_t hilo3;
pthread_create(&hilo3, NULL, Principal::setValuesThread, this);
pthread_join(hilo3,NULL);
}
But if Principal is a Qt widget (and I suppose it is), this code won't work because in Qt you can access widgets from the main thread only.
If you want to have some heavy calculations in a worker thread and then pass the results to your widget, you can use QThread and Qt signals/slots mechanism.
A simple example:
class MyThread : public QThread
{
Q_OBJECT
public:
MyThread(QObject *parent = 0);
void run();
signals:
void dataReady(QString data);
}
void MyThread::run()
{
QString data = "Some data calculated in this worker thread";
emit dataReady(data);
}
class Principal
{
...
public slots:
void setData(QString data);
}
void Principal::setData(QString data)
{
ui->someLabel->setText(data);
}
void Principal::on_Start_Cargador_clicked()
{
MyThread *thread = new MyThread;
connect(thread, SIGNAL(dataReady(QString)), this, SLOT(setData(QString()));
connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
thread->start();
}
Here is some related articles on Qt multithreading technologies:
http://doc.qt.io/qt-5/thread-basics.html
http://doc.qt.io/qt-5/threads-technologies.html
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";
}
int Core::getAuth()
{
LoginDialog *login = new LoginDialog();
int r = login->exec();
delete login;
return r;
}
void Core::appExit() // connected to qapplication aboutToQuit
{
qDebug() << "Core::appExit called";
}
void Core::preInit() // called after getAuth im main.cpp
{
qDebug() << "Core::preInit called";
}
void Core::appMenuTriggered( QAction *action )
{
qDebug() << "action triggered";
}
void Core::appInit()
{
mwnd = new MainWindow();
mwnd->show();
qDebug() << "Core::appInit called";
}
I'm trying to connect mainwindow menubar signal to core slot like this:
connect(mwnd->menuBar(), SIGNAL(triggered()), this, SLOT(appMenuTriggered()));
But it doesn't work. Im new to c++ and Qt. How to connect this?
Or maybe there is better way to handle mainwindow actions to other programm parts.
UPD
Problem solved. Forget to include QMenuBar
You have to give the full function spec in the SIGNAL and SLOT parameters (but without the argument names). Like this:
connect(mwnd->menuBar(),
SIGNAL(triggered(QAction*)),
this,
SLOT(appMenuTriggered(QAction*)));
If you debug such code in Qt Creator, the connect function will write diagnostic error messages to the Application Output pane when it doesn't find a signal or a slot. I suggest that you find these error messages before you fix your problem, so that you know where to look in future. It's very easy to get signals and slots wrong!