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using QKeyEvents

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  • SGaistS SGaist

    The last implementation I saw does not call it at all which means that all events are filtered out.

    To check, comment out the filter installation and see if it does work correctly.

    mzimmersM Offline
    mzimmersM Offline
    mzimmers
    wrote on last edited by
    #19

    @SGaist let's make sure we're talking about the same thing. Here's where I create the filter:

        // create and connect a KeyPress object.
        m_keyPress = new KeyPress(this);
        connect(m_keyPress, &KeyPress::keyEvent, this, &Widget::handleKeyEvent);
        installEventFilter(m_keyPress);
    
        // hide the button for the NICs window.
    //    ui->pushButtonNics->setVisible(false);
    

    You'll notice that the last line is commented out. And, it works. So it would seem that it has something to do with the filter...?

    1 Reply Last reply
    0
    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #20

      Can you provide a minimal compilable example that shows the behaviour ?
      Si au can check on my side what is going on.

      Interested in AI ? www.idiap.ch
      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

      mzimmersM 1 Reply Last reply
      0
      • SGaistS SGaist

        Can you provide a minimal compilable example that shows the behaviour ?
        Si au can check on my side what is going on.

        mzimmersM Offline
        mzimmersM Offline
        mzimmers
        wrote on last edited by
        #21

        @SGaist

        keypress.h

        #ifndef KEYPRESS_H
        #define KEYPRESS_H
        
        #include <QWidget>
        #include <QtGui>
        
        class KeyPress : public QObject
        {
            Q_OBJECT
        public:
            explicit KeyPress(QWidget *parent = nullptr);
        protected:
            bool eventFilter(QObject *obj, QEvent *ev) override;
        
        signals:
            void keyEvent(QEvent event, int key);
        };
        
        #endif // KEYPRESS_H
        

        keypress.cpp

        #include "keypress.h"
        
        KeyPress::KeyPress(QWidget *parent) : QObject (parent)
        {
        }
        
        bool KeyPress::eventFilter(QObject *obj, QEvent *ev)
        {
            Q_UNUSED(obj)
        
            bool rc = false;
            int key;
            QKeyEvent *qke;
        
            if (ev->type() == QEvent::ShortcutOverride || ev->type() == QEvent::KeyRelease)
            {
                qke = static_cast<QKeyEvent *>(ev);
                key = qke->key();
        
                // don't bother signaling when the key isn't meaningful to us.
                if (key == 'c' || key == 'C' || key == 'd' || key == 'D')
                {
                    emit keyEvent(*ev, key);
                }
                rc = true;
            }
            else
            {
                rc = QObject::eventFilter(obj, ev);
            }
            return rc;
        }
        

        Let me know if there's something more you want to look at...thanks.

        1 Reply Last reply
        0
        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #22

          A minimal widget that you install that filter on would be nice :-)

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

          1 Reply Last reply
          0
          • mzimmersM Offline
            mzimmersM Offline
            mzimmers
            wrote on last edited by
            #23

            widget.h

            #ifndef WIDGET_H
            #define WIDGET_H
            
            #include <QWidget>
            #include "keypress.h"
            
            namespace Ui {
                class Widget;
            }
            
            class Widget : public QWidget
            {
                Q_OBJECT
            
            private:
                Ui::Widget *ui;
                KeyPress *m_keyPress = nullptr;
                bool C_pressed = false;
                bool D_pressed = false;
            
            public:
                explicit Widget(QWidget *parent = nullptr);
                ~Widget();
            private slots:
                void on_pushButtonQuit_clicked();
                void on_pushButtonNics_clicked();
                void handleKeyEvent(QEvent event, int key);
            signals:
                void quitButtonPushed(int rc);
            };
            #endif // WIDGET_H
            
            

            widget.cpp

            #include <iostream>
            #include <sstream>
            #include <stdio.h>
            
            #include <QDebug>
            
            #include "editdialog.h"
            #include "nics.h"
            #include "widget.h"
            #include "ui_widget.h"
            
            using namespace std;
            
            Widget::Widget(QWidget *parent) :
                QWidget(parent),
                ui(new Ui::Widget)
            {
                ui->setupUi(this);
            
                // create and connect a KeyPress object.
                m_keyPress = new KeyPress(this);
                connect(m_keyPress, &KeyPress::keyEvent, this, &Widget::handleKeyEvent);
                installEventFilter(m_keyPress);
            
                // hide the button for the NICs window.
                ui->pushButtonNics->setVisible(false);
            }
            
            Widget::~Widget()
            {
                delete ui;
            }
            
            
            void Widget::on_pushButtonQuit_clicked()
            {
                emit quitButtonPushed(0);
            }
            
            void Widget::handleKeyEvent(QEvent event, int key)
            {
                if (event.type() == QEvent::ShortcutOverride)
                {
                    if (key == 'c' || key == 'C')
                    {
                        C_pressed = true;
                    }
                    else if ((key == 'd' || key == 'D'))
                    {
                        D_pressed = true;
                    }
            
                }
                else if (event.type() == QEvent::KeyRelease)
                {
                    if (key == 'c' || key == 'C')
                    {
                        C_pressed = false;
                    }
                    else if ((key == 'd' || key == 'D'))
                    {
                        D_pressed = false;
                    }
                }
            
                if (C_pressed && D_pressed)
                {
                    ui->pushButtonNics->setVisible(true);
                }
                else
                {
                    ui->pushButtonNics->setVisible(false);
                }
            }
            
            
            
            void Widget::on_pushButtonNics_clicked()
            {
                Nics nics(this);
                nics.exec();
            }
            

            You'll want to connect the Widget signal to something. Sorry...this was as compact as I dared make it.

            Thanks for looking at this.

            1 Reply Last reply
            0
            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #24

              Since I don't have the .ui file I modified the code a bit.

              I created a QPushButton and did an explicit connection and it worked was expected.

              Interested in AI ? www.idiap.ch
              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

              mzimmersM 1 Reply Last reply
              0
              • SGaistS SGaist

                Since I don't have the .ui file I modified the code a bit.

                I created a QPushButton and did an explicit connection and it worked was expected.

                mzimmersM Offline
                mzimmersM Offline
                mzimmers
                wrote on last edited by
                #25

                @SGaist well, doesn't that tear the rag right off the bush.

                What exactly did you mean by "explicit" connection?

                1 Reply Last reply
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                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #26

                  By explicit I meant writing the connect statement. Currently you are using the connectSlotsByName feature that is called as part of setupUi.

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                  1 Reply Last reply
                  1
                  • mzimmersM Offline
                    mzimmersM Offline
                    mzimmers
                    wrote on last edited by
                    #27

                    OK...I added the explicit connection in widget.cpp:

                        connect(ui->pushButtonNics, &QPushButton::clicked, this, &Widget::on_pushButtonNics_clicked);
                    

                    Here's my widget.ui:

                    <?xml version="1.0" encoding="UTF-8"?>
                    <ui version="4.0">
                     <class>Widget</class>
                     <widget class="QWidget" name="Widget">
                      <property name="geometry">
                       <rect>
                        <x>0</x>
                        <y>0</y>
                        <width>320</width>
                        <height>160</height>
                       </rect>
                      </property>
                      <property name="sizePolicy">
                       <sizepolicy hsizetype="Preferred" vsizetype="MinimumExpanding">
                        <horstretch>0</horstretch>
                        <verstretch>0</verstretch>
                       </sizepolicy>
                      </property>
                      <property name="minimumSize">
                       <size>
                        <width>320</width>
                        <height>160</height>
                       </size>
                      </property>
                      <property name="windowTitle">
                       <string>Discovery Utility</string>
                      </property>
                      <widget class="QPushButton" name="pushButtonNics">
                       <property name="geometry">
                        <rect>
                         <x>130</x>
                         <y>50</y>
                         <width>75</width>
                         <height>23</height>
                        </rect>
                       </property>
                       <property name="text">
                        <string>NICs</string>
                       </property>
                      </widget>
                     </widget>
                     <layoutdefault spacing="6" margin="11"/>
                     <resources/>
                     <connections/>
                    </ui>
                    

                    And, just for good measure, here's main.cpp:

                    #include <QApplication>
                    
                    #include <stdio.h>
                    
                    #include "widget.h"
                    
                    using namespace std;
                    
                    int main(int argc, char *argv[])
                    {
                        int rc;
                        QApplication a(argc, argv);
                        Widget *widget;
                    
                        widget = new Widget();
                        widget->show();
                        rc = a.exec();
                        return rc;
                    }
                    

                    This is my entire project, except for the pro file itself:

                    QT       += core gui network serialport xml
                    
                    greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
                    
                    TARGET = discovery_utility_test
                    DEFINES += QT_DEPRECATED_WARNINGS
                    SOURCES += \
                    	keypress.cpp \
                    	main.cpp \
                    	nics.cpp \
                    	widget.cpp
                    
                    HEADERS += \
                    	keypress.h \
                    	nics.h \
                    	widget.h \
                    
                    FORMS += \
                    	nics.ui \
                    	widget.ui
                    

                    Could it possibly be due to the way that I'm building it? Or, maybe a Windows issue (you're testing on Linux, right)?

                    Thanks...

                    1 Reply Last reply
                    0
                    • mzimmersM Offline
                      mzimmersM Offline
                      mzimmers
                      wrote on last edited by
                      #28

                      This problem has to do with setting the button's visibility. If I disable this line in my widget c'tor:

                      //    ui->pushButtonNics->setVisible(false);
                      

                      My slot receives the signal, and opens the Nics dialog. After the dialog closes, I set the button to not visible, and the problem recurs.

                      This problem exists on Windows 10, but not on MacOS. Could it be a bug?

                      1 Reply Last reply
                      0
                      • SGaistS Offline
                        SGaistS Offline
                        SGaist
                        Lifetime Qt Champion
                        wrote on last edited by
                        #29

                        One silly test, did you try to make the button invisible after calling connect. AFAIK, it should have no relation but it's worth a shot.

                        Interested in AI ? www.idiap.ch
                        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                        mzimmersM 1 Reply Last reply
                        0
                        • SGaistS SGaist

                          One silly test, did you try to make the button invisible after calling connect. AFAIK, it should have no relation but it's worth a shot.

                          mzimmersM Offline
                          mzimmersM Offline
                          mzimmers
                          wrote on last edited by
                          #30

                          @SGaist yes, that's how I had it:

                          Widget::Widget(QWidget *parent) :
                              QWidget(parent),
                              ui(new Ui::Widget)
                          {
                              ui->setupUi(this);
                          
                              // create and connect a KeyPress object.
                              m_keyPress = new KeyPress(this);
                              connect(m_keyPress, &KeyPress::keyEvent, this, &Widget::handleKeyEvent);
                              connect(ui->pushButtonNics, &QPushButton::clicked, this, &Widget::on_pushButtonNics_clicked);
                              installEventFilter(m_keyPress);
                          
                              // hide the button for the NICs window.
                          //    ui->pushButtonNics->setVisible(false);
                          }
                          
                          1 Reply Last reply
                          0
                          • mzimmersM Offline
                            mzimmersM Offline
                            mzimmers
                            wrote on last edited by
                            #31

                            Update: I submitted a bug report on this; no movement on it yet.

                            One of my users noticed that the application is now rather CPU-intensive. I verified that it was the key filter by disabling this code in my main widget:

                                m_keyPress = new KeyPress(this);
                                connect(m_keyPress, &KeyPress::keyEvent, this, &Widget::handleKeyEvent);
                                installEventFilter(m_keyPress);
                            

                            Here's the filter:

                            bool KeyPress::eventFilter(QObject *obj, QEvent *ev)
                            {
                                Q_UNUSED(obj)
                            
                                bool rc = false;
                                int key;
                                QKeyEvent *qke;
                                QEvent::Type type = ev->type();
                                if (type == QEvent::ShortcutOverride || type == QEvent::KeyRelease)
                                {
                                    qke = static_cast<QKeyEvent *>(ev);
                                    key = qke->key();
                            
                                    // don't bother signaling when the key isn't meaningful to us.
                                    if (key == 'c' || key == 'C' || key == 'd' || key == 'D')
                                    {
                                        emit keyEvent(*ev, key);
                                    }
                                    rc = true;
                                }
                                else
                                {
                                    rc = QObject::eventFilter(obj, ev);
                                }
                                return rc;
                            }
                            

                            I don't see anything really inefficient in my code, but with this enabled, the app uses ~15% of my CPU (on an i3) at idle. Is this to be expected, or am I doing something wrong?

                            Thanks...

                            1 Reply Last reply
                            0
                            • SGaistS Offline
                              SGaistS Offline
                              SGaist
                              Lifetime Qt Champion
                              wrote on last edited by
                              #32

                              What type of widgets are you checking ?
                              You can add an additional check for the obj parameter class to avoid further checks.

                              Interested in AI ? www.idiap.ch
                              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                              JonBJ mzimmersM 2 Replies Last reply
                              0
                              • SGaistS SGaist

                                What type of widgets are you checking ?
                                You can add an additional check for the obj parameter class to avoid further checks.

                                JonBJ Offline
                                JonBJ Offline
                                JonB
                                wrote on last edited by
                                #33

                                @SGaist
                                If @mzimmers says:

                                but with this enabled, the app uses ~15% of my CPU (on an i3) at idle

                                assuming "idle" means not pressing any key, why is this KeyPress::eventFilter() being hit at all, let alone loads of times to use that CPU?

                                mzimmersM 1 Reply Last reply
                                0
                                • SGaistS SGaist

                                  What type of widgets are you checking ?
                                  You can add an additional check for the obj parameter class to avoid further checks.

                                  mzimmersM Offline
                                  mzimmersM Offline
                                  mzimmers
                                  wrote on last edited by
                                  #34

                                  @SGaist well, maybe that's my problem -- I'm checking the entire QWidget. (The idea was to reveal hidden buttons when certain keys were pressed.) Given that, I'm not sure there's any meaningful obj parameter checking I can do.

                                  1 Reply Last reply
                                  0
                                  • JonBJ JonB

                                    @SGaist
                                    If @mzimmers says:

                                    but with this enabled, the app uses ~15% of my CPU (on an i3) at idle

                                    assuming "idle" means not pressing any key, why is this KeyPress::eventFilter() being hit at all, let alone loads of times to use that CPU?

                                    mzimmersM Offline
                                    mzimmersM Offline
                                    mzimmers
                                    wrote on last edited by
                                    #35

                                    @JonB I suspect I'm doing something wrong with my use of the filter, but I'm not sure what to change. I think my filterEvent() is being called for all events, not just for key events.

                                    JonBJ 1 Reply Last reply
                                    0
                                    • mzimmersM mzimmers

                                      @JonB I suspect I'm doing something wrong with my use of the filter, but I'm not sure what to change. I think my filterEvent() is being called for all events, not just for key events.

                                      JonBJ Offline
                                      JonBJ Offline
                                      JonB
                                      wrote on last edited by
                                      #36

                                      @mzimmers said in using QKeyEvents:

                                      I think my filterEvent() is being called for all events, not just for key events.

                                      I suspect that is more like it ;-) I would worry about that before anything else :)

                                      Use a debugger or qDebug()s to at least see when your filter is being hit, when the user isn't doing anything?

                                      mzimmersM 1 Reply Last reply
                                      0
                                      • JonBJ JonB

                                        @mzimmers said in using QKeyEvents:

                                        I think my filterEvent() is being called for all events, not just for key events.

                                        I suspect that is more like it ;-) I would worry about that before anything else :)

                                        Use a debugger or qDebug()s to at least see when your filter is being hit, when the user isn't doing anything?

                                        mzimmersM Offline
                                        mzimmersM Offline
                                        mzimmers
                                        wrote on last edited by
                                        #37

                                        @JonB

                                            qDebug() << QTime::currentTime().toString();
                                        

                                        Got about 6000 hits in ~2 seconds of run time. That explains the CPU usage.

                                        I have no idea what could possibly be generating that many events, though.

                                        JonBJ 1 Reply Last reply
                                        0
                                        • mzimmersM mzimmers

                                          @JonB

                                              qDebug() << QTime::currentTime().toString();
                                          

                                          Got about 6000 hits in ~2 seconds of run time. That explains the CPU usage.

                                          I have no idea what could possibly be generating that many events, though.

                                          JonBJ Offline
                                          JonBJ Offline
                                          JonB
                                          wrote on last edited by
                                          #38

                                          @mzimmers
                                          Start by debugging out ev->type()!

                                          mzimmersM 1 Reply Last reply
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