Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. Simulate left mouse button unclick (release button)
Forum Update on Monday, May 27th 2025

Simulate left mouse button unclick (release button)

Scheduled Pinned Locked Moved Solved General and Desktop
31 Posts 3 Posters 14.3k Views
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • A Andrey Shmelew

    @mrjj
    Hello and Happy New Year!

    I installed VLC media player on my beaglebone, and have been playing with controls (combobox, scrollbars etc...), and all was going well, no bugs with comboboxes, touch screen clicks and releases fine.
    I noticed that combobox in VLC player and combobox in QT are differented of each other.

    VLC acceps the touch fully as a mouse, i suppose.

    mrjjM Offline
    mrjjM Offline
    mrjj
    Lifetime Qt Champion
    wrote on last edited by
    #14

    @Andrey-Shmelew
    Hi
    Happy new year to you too

    Ok it does sound like it is working as it should. Maybe VLC is very touch friendly.

    Can we test with one app ( nothing as well used with touch as VLC ) to test ?

    Still think its just controller that slips a mouse up sometimes but not sure yet.

    A 1 Reply Last reply
    0
    • mrjjM mrjj

      @Andrey-Shmelew
      Hi
      Happy new year to you too

      Ok it does sound like it is working as it should. Maybe VLC is very touch friendly.

      Can we test with one app ( nothing as well used with touch as VLC ) to test ?

      Still think its just controller that slips a mouse up sometimes but not sure yet.

      A Offline
      A Offline
      Andrey Shmelew
      wrote on last edited by
      #15

      @mrjj said in Simulate left mouse button unclick (release button):

      Can we test with one app ( nothing as well used with touch as VLC ) to test ?

      yes, sure, i will try evrethyng i can

      mrjjM 1 Reply Last reply
      0
      • A Andrey Shmelew

        @mrjj said in Simulate left mouse button unclick (release button):

        Can we test with one app ( nothing as well used with touch as VLC ) to test ?

        yes, sure, i will try evrethyng i can

        mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by mrjj
        #16

        @Andrey-Shmelew
        Super
        Did you also check with main window that
        void MainWindow::mouseReleaseEvent(QMouseEvent* event)
        {
        qDebug() << ("button Released");
        }

        is always called?
        Make sure only to click on the mainwindow.

        A 1 Reply Last reply
        0
        • mrjjM mrjj

          @Andrey-Shmelew
          Super
          Did you also check with main window that
          void MainWindow::mouseReleaseEvent(QMouseEvent* event)
          {
          qDebug() << ("button Released");
          }

          is always called?
          Make sure only to click on the mainwindow.

          A Offline
          A Offline
          Andrey Shmelew
          wrote on last edited by Andrey Shmelew
          #17

          @mrjj said in Simulate left mouse button unclick (release button):

          is always called

          if only i did not press combobox...

          As soon as I clicked combobox, no matter how many times I clicked on the mainwindow, label_7 is always "Only left button"

          qDebug() << ("button Released"); is not working in linux app, so i use label_7 as debug out

          mrjjM 1 Reply Last reply
          0
          • A Andrey Shmelew

            @mrjj said in Simulate left mouse button unclick (release button):

            is always called

            if only i did not press combobox...

            As soon as I clicked combobox, no matter how many times I clicked on the mainwindow, label_7 is always "Only left button"

            qDebug() << ("button Released"); is not working in linux app, so i use label_7 as debug out

            mrjjM Offline
            mrjjM Offline
            mrjj
            Lifetime Qt Champion
            wrote on last edited by
            #18

            @Andrey-Shmelew
            Yes combo is special as it drop down a floating window and use event filer for selection so
            it is not canceled correctly, it will then eat all events and nothing else can be clicked.

            ehh qDebug() not working in linux ? you mean outside Creator or ?
            Dont matter. Label is fine :)

            A 1 Reply Last reply
            1
            • mrjjM mrjj

              @Andrey-Shmelew
              Yes combo is special as it drop down a floating window and use event filer for selection so
              it is not canceled correctly, it will then eat all events and nothing else can be clicked.

              ehh qDebug() not working in linux ? you mean outside Creator or ?
              Dont matter. Label is fine :)

              A Offline
              A Offline
              Andrey Shmelew
              wrote on last edited by
              #19

              @mrjj
              Hello!

              So, the problem is not solved,
              should i use events filter?

              thanks!

              mrjjM 1 Reply Last reply
              0
              • A Andrey Shmelew

                @mrjj
                Hello!

                So, the problem is not solved,
                should i use events filter?

                thanks!

                mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by mrjj
                #20

                @Andrey-Shmelew
                well, i would dig a bit deeper into what is going on.
                I never seen combo not work like that.
                Seems something else than missing events.

                But yes, you can most likely work around using event filters but there might surface other stuff
                like broken drag and drop or something as its not a bug in combobox ( no other reports) as such so
                something else is not as expected with the touch.

                I tried at work with touch screen and could not reproduce it so Im a bit lost why
                its not just closing its dropdown.

                I think it will/might be a mess with eventfilter
                but if you only have one combobox you
                need to fix it should be ok
                but if you use combos all over program i would
                go for better solution.

                A 1 Reply Last reply
                1
                • mrjjM mrjj

                  @Andrey-Shmelew
                  well, i would dig a bit deeper into what is going on.
                  I never seen combo not work like that.
                  Seems something else than missing events.

                  But yes, you can most likely work around using event filters but there might surface other stuff
                  like broken drag and drop or something as its not a bug in combobox ( no other reports) as such so
                  something else is not as expected with the touch.

                  I tried at work with touch screen and could not reproduce it so Im a bit lost why
                  its not just closing its dropdown.

                  I think it will/might be a mess with eventfilter
                  but if you only have one combobox you
                  need to fix it should be ok
                  but if you use combos all over program i would
                  go for better solution.

                  A Offline
                  A Offline
                  Andrey Shmelew
                  wrote on last edited by
                  #21

                  @mrjj
                  Unfortunately, i use combos all over program. I want to use comboboxes for configure my device. if you could not reproduce it, maybe it happens because of my touch's non-correct work. If i could make any help for you for help me ...

                  mrjjM raven-worxR 2 Replies Last reply
                  0
                  • A Andrey Shmelew

                    @mrjj
                    Unfortunately, i use combos all over program. I want to use comboboxes for configure my device. if you could not reproduce it, maybe it happens because of my touch's non-correct work. If i could make any help for you for help me ...

                    mrjjM Offline
                    mrjjM Offline
                    mrjj
                    Lifetime Qt Champion
                    wrote on last edited by mrjj
                    #22

                    @Andrey-Shmelew

                    Hmm, I asked another mod here for some input (later) as there is something
                    funky here. Maybe im overlooking something.
                    If your touch acts as pure touch or is faulty then other controls should also have issues.

                    But since we do not have any event trace is very unclear what is happening.
                    Also as far as I know, the drop down part of the combobox is already using event filter.
                    So its not sure event filters are a good/easy fix.

                    I think i would still dig deeper to find real reason. ( look in Qt source)

                    Alternatively, make my own combo box and control the dropdown with lost focus if possible.
                    Didnt check the code so not sure how it handles the dropdown.

                    1 Reply Last reply
                    1
                    • A Andrey Shmelew

                      @mrjj
                      Unfortunately, i use combos all over program. I want to use comboboxes for configure my device. if you could not reproduce it, maybe it happens because of my touch's non-correct work. If i could make any help for you for help me ...

                      raven-worxR Offline
                      raven-worxR Offline
                      raven-worx
                      Moderators
                      wrote on last edited by raven-worx
                      #23

                      @Andrey-Shmelew
                      whats your touch screen model?
                      Whats your input mode (evdev, tslib, libinput) used?
                      What is your used Qt platform (X, LinuxFB, EGLFS)?

                      Just to make sure: you are using QtWidgets right, not QML?

                      btw. VLC also uses Qt for it's GUI. But i currently don't know which version.
                      Can you also try to use Qt 5.8 RC if you encounter the same issues?

                      Also you could log all events like the following. Start the application from the console and you should see the output in stdout.

                      qApp->installEventFilter( this );
                      ...
                      bool eventFilter( QObject* watched, QEvent* event )
                      {
                           switch( event->type() )
                           {
                                     case QEvent::MousePressEvent:
                                     case QEvent::MouseReleaseEvent:
                                     case QEvent::TouchBegin:
                                     case QEvent::TouchCancel:
                                     case QEvent::TouchEnd:
                                              qDebug() << int(event->type()) << watched;
                                    break;
                           }
                      
                           return BaseClass::eventFilter(watched,event);
                      }
                      

                      --- SUPPORT REQUESTS VIA CHAT WILL BE IGNORED ---
                      If you have a question please use the forum so others can benefit from the solution in the future

                      A 2 Replies Last reply
                      3
                      • raven-worxR raven-worx

                        @Andrey-Shmelew
                        whats your touch screen model?
                        Whats your input mode (evdev, tslib, libinput) used?
                        What is your used Qt platform (X, LinuxFB, EGLFS)?

                        Just to make sure: you are using QtWidgets right, not QML?

                        btw. VLC also uses Qt for it's GUI. But i currently don't know which version.
                        Can you also try to use Qt 5.8 RC if you encounter the same issues?

                        Also you could log all events like the following. Start the application from the console and you should see the output in stdout.

                        qApp->installEventFilter( this );
                        ...
                        bool eventFilter( QObject* watched, QEvent* event )
                        {
                             switch( event->type() )
                             {
                                       case QEvent::MousePressEvent:
                                       case QEvent::MouseReleaseEvent:
                                       case QEvent::TouchBegin:
                                       case QEvent::TouchCancel:
                                       case QEvent::TouchEnd:
                                                qDebug() << int(event->type()) << watched;
                                      break;
                             }
                        
                             return BaseClass::eventFilter(watched,event);
                        }
                        
                        A Offline
                        A Offline
                        Andrey Shmelew
                        wrote on last edited by Andrey Shmelew
                        #24

                        @raven-worx
                        This is my display : http://www.waveshare.com/10.1inch-hdmi-lcd-b-with-case.htm
                        i dont know inpute mode (maybe this is a reason of a bug)
                        i also dont know qt platform (maybe Qt Creator 4.1.0
                        Основан на Qt 5.7.0 (MSVC 2013, 32 бита) is answer), and i built qt everywere with gcc arm none eabi compiler.
                        I use QtWidgets, not QML, i am sure.
                        OK I think i can try QT 5.8 RC
                        Ok i will log all events following your code

                        here is video demonstrates how combo works https://drive.google.com/file/d/0ByPoVqOCWO2IVERuMkMzTmZsMjA/view

                        raven-worxR 1 Reply Last reply
                        0
                        • A Andrey Shmelew

                          @raven-worx
                          This is my display : http://www.waveshare.com/10.1inch-hdmi-lcd-b-with-case.htm
                          i dont know inpute mode (maybe this is a reason of a bug)
                          i also dont know qt platform (maybe Qt Creator 4.1.0
                          Основан на Qt 5.7.0 (MSVC 2013, 32 бита) is answer), and i built qt everywere with gcc arm none eabi compiler.
                          I use QtWidgets, not QML, i am sure.
                          OK I think i can try QT 5.8 RC
                          Ok i will log all events following your code

                          here is video demonstrates how combo works https://drive.google.com/file/d/0ByPoVqOCWO2IVERuMkMzTmZsMjA/view

                          raven-worxR Offline
                          raven-worxR Offline
                          raven-worx
                          Moderators
                          wrote on last edited by raven-worx
                          #25

                          @Andrey-Shmelew
                          in the video the mouse cursor changes it's shape (to Qt::IBeamCursor), from then on your widgets do not react anymore.
                          You can also log the focus changes by connecting to QApplication::focusChanged() signal. It would be interesting what's the focus widget is in that case.

                          Maybe you use QWidget::grabMouse() in this widget?

                          Can you also please set QT_DEBUG_PLUGINS=1 environment variable and post the output from the console. Maybe before/after you try the other debug output.
                          This shows what plugins are being loaded.

                          --- SUPPORT REQUESTS VIA CHAT WILL BE IGNORED ---
                          If you have a question please use the forum so others can benefit from the solution in the future

                          A 1 Reply Last reply
                          1
                          • raven-worxR raven-worx

                            @Andrey-Shmelew
                            in the video the mouse cursor changes it's shape (to Qt::IBeamCursor), from then on your widgets do not react anymore.
                            You can also log the focus changes by connecting to QApplication::focusChanged() signal. It would be interesting what's the focus widget is in that case.

                            Maybe you use QWidget::grabMouse() in this widget?

                            Can you also please set QT_DEBUG_PLUGINS=1 environment variable and post the output from the console. Maybe before/after you try the other debug output.
                            This shows what plugins are being loaded.

                            A Offline
                            A Offline
                            Andrey Shmelew
                            wrote on last edited by Andrey Shmelew
                            #26

                            @raven-worx
                            i added QApplication::focusChanged() signal:

                            int main(int argc, char *argv[])
                            {
                                QApplication a(argc, argv);
                                MainWindow w;
                                QObject::connect(&a, SIGNAL(focusChanged(QWidget*,QWidget*)), &w, SLOT(textupdate()));
                                w.show();
                                return a.exec();
                            }
                            

                            then added a slot:

                            void MainWindow::textupdate()
                            {
                            QWidget * fw = qApp->focusWidget();
                            ui->textEdit_3->setText(ui->textEdit_3->toPlainText() + " | " + fw->objectName());
                            }
                            

                            accordingly, i can see focused widget name, right?
                            After it, i noticed strange behaviour:
                            after some clicks on comboboxes, it becomes impossible to control all of widgets besides textEdit widgets (and sometimes... dial). Thats all. All other widgets (sliders, combos) are dead. And strange that when i click on textEdit, mouse cursor is always at the begin.

                            And the following video : https://drive.google.com/open?id=0ByPoVqOCWO2IMmdlMk8xTEVoa0U

                            PS, sometimes when bug happens, i can select text in textEdit by my finger (as if I hold down the left mouse button), so i made a conclusion that "touch mouse button" didnt released properly. And the video:
                            https://drive.google.com/open?id=0ByPoVqOCWO2IS2lIQUpBSlNPWDA

                            trying QT 5.8 RC did not bring good results

                            case QEvent::MousePressEvent:
                            case QEvent::MouseReleaseEvent:

                            MousePressEvent and MouseReleaseEvent are not exsist

                            PPS: After i connect regular mouse and click left button, all becomes normal.

                            1 Reply Last reply
                            0
                            • raven-worxR raven-worx

                              @Andrey-Shmelew
                              whats your touch screen model?
                              Whats your input mode (evdev, tslib, libinput) used?
                              What is your used Qt platform (X, LinuxFB, EGLFS)?

                              Just to make sure: you are using QtWidgets right, not QML?

                              btw. VLC also uses Qt for it's GUI. But i currently don't know which version.
                              Can you also try to use Qt 5.8 RC if you encounter the same issues?

                              Also you could log all events like the following. Start the application from the console and you should see the output in stdout.

                              qApp->installEventFilter( this );
                              ...
                              bool eventFilter( QObject* watched, QEvent* event )
                              {
                                   switch( event->type() )
                                   {
                                             case QEvent::MousePressEvent:
                                             case QEvent::MouseReleaseEvent:
                                             case QEvent::TouchBegin:
                                             case QEvent::TouchCancel:
                                             case QEvent::TouchEnd:
                                                      qDebug() << int(event->type()) << watched;
                                            break;
                                   }
                              
                                   return BaseClass::eventFilter(watched,event);
                              }
                              
                              A Offline
                              A Offline
                              Andrey Shmelew
                              wrote on last edited by Andrey Shmelew
                              #27

                              @raven-worx said in Simulate left mouse button unclick (release button):

                              Also you could log all events like the following. Start the application from the console and you should see the output in stdout.

                              this is code to see events in event filter:

                              bool MainWindow::eventFilter(QObject *obj, QEvent *event)
                              {
                                  switch( event->type() ){
                                  case QEvent::MouseButtonDblClick:
                                      //        qDebug() << "Mouse Button Double Clicked";
                                      ui->textEdit_3->setText("Mouse Double Clicked");
                                      break;
                                  case QEvent::MouseButtonPress:
                                      //        qDebug() << "Mouse Button Pressed";
                                      ui->textEdit_3->setText("Mouse Button Pressed");
                                      break;
                                  case QEvent::MouseButtonRelease:
                                      //        qDebug() << "Mouse Button Released";
                                      ui->textEdit_3->setText("Mouse Button Released");
                                      break;
                              
                                  case QEvent::TouchBegin:
                                      //        qDebug() << "TouchBegin";
                                      ui->textEdit_3->setText("TouchBegin");
                                      break;
                              
                                  case QEvent::TouchEnd:
                                      //        qDebug() << "TouchEnd";
                                      ui->textEdit_3->setText("TouchEnd");
                                      break;
                              
                                  case QEvent::TouchCancel:
                                      //        qDebug() << "TouchCancel";
                                      ui->textEdit_3->setText("TouchCancel");
                                      break;
                              
                                  case QEvent::TouchUpdate:
                                      //qDebug() << "TouchUpdate";
                                      ui->textEdit_3->setText("TouchUpdate");
                                      break;
                              
                                  default:
                                      break;
                                  }
                                  // pass the event on to the parent class
                                  return QMainWindow::eventFilter(obj, event);
                              }
                              

                              So, i noticed that mouse when i touch widgets, release event is called but... not always...
                              but if i connect mouse instead of touch screen, and press left button, it becomes OK.

                              A 1 Reply Last reply
                              0
                              • A Andrey Shmelew

                                @raven-worx said in Simulate left mouse button unclick (release button):

                                Also you could log all events like the following. Start the application from the console and you should see the output in stdout.

                                this is code to see events in event filter:

                                bool MainWindow::eventFilter(QObject *obj, QEvent *event)
                                {
                                    switch( event->type() ){
                                    case QEvent::MouseButtonDblClick:
                                        //        qDebug() << "Mouse Button Double Clicked";
                                        ui->textEdit_3->setText("Mouse Double Clicked");
                                        break;
                                    case QEvent::MouseButtonPress:
                                        //        qDebug() << "Mouse Button Pressed";
                                        ui->textEdit_3->setText("Mouse Button Pressed");
                                        break;
                                    case QEvent::MouseButtonRelease:
                                        //        qDebug() << "Mouse Button Released";
                                        ui->textEdit_3->setText("Mouse Button Released");
                                        break;
                                
                                    case QEvent::TouchBegin:
                                        //        qDebug() << "TouchBegin";
                                        ui->textEdit_3->setText("TouchBegin");
                                        break;
                                
                                    case QEvent::TouchEnd:
                                        //        qDebug() << "TouchEnd";
                                        ui->textEdit_3->setText("TouchEnd");
                                        break;
                                
                                    case QEvent::TouchCancel:
                                        //        qDebug() << "TouchCancel";
                                        ui->textEdit_3->setText("TouchCancel");
                                        break;
                                
                                    case QEvent::TouchUpdate:
                                        //qDebug() << "TouchUpdate";
                                        ui->textEdit_3->setText("TouchUpdate");
                                        break;
                                
                                    default:
                                        break;
                                    }
                                    // pass the event on to the parent class
                                    return QMainWindow::eventFilter(obj, event);
                                }
                                

                                So, i noticed that mouse when i touch widgets, release event is called but... not always...
                                but if i connect mouse instead of touch screen, and press left button, it becomes OK.

                                A Offline
                                A Offline
                                Andrey Shmelew
                                wrote on last edited by
                                #28

                                Ok, the problem is solved,

                                i have recieved a new touch-panel, and it is working fine, mouse released lert button after i release my finger.

                                Thanks for help

                                mrjjM 1 Reply Last reply
                                1
                                • A Andrey Shmelew

                                  Ok, the problem is solved,

                                  i have recieved a new touch-panel, and it is working fine, mouse released lert button after i release my finger.

                                  Thanks for help

                                  mrjjM Offline
                                  mrjjM Offline
                                  mrjj
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #29

                                  @Andrey-Shmelew
                                  So it was just a faulty driver or something?

                                  A 1 Reply Last reply
                                  0
                                  • mrjjM mrjj

                                    @Andrey-Shmelew
                                    So it was just a faulty driver or something?

                                    A Offline
                                    A Offline
                                    Andrey Shmelew
                                    wrote on last edited by Andrey Shmelew
                                    #30

                                    @mrjj

                                    it was faulty Touch Hardware Driver IMHO

                                    mrjjM 1 Reply Last reply
                                    1
                                    • A Andrey Shmelew

                                      @mrjj

                                      it was faulty Touch Hardware Driver IMHO

                                      mrjjM Offline
                                      mrjjM Offline
                                      mrjj
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #31

                                      @Andrey-Shmelew

                                      yep I suspected that
                                      But HW is hard to debug remotely :)

                                      Happy programming

                                      1 Reply Last reply
                                      1

                                      • Login

                                      • Login or register to search.
                                      • First post
                                        Last post
                                      0
                                      • Categories
                                      • Recent
                                      • Tags
                                      • Popular
                                      • Users
                                      • Groups
                                      • Search
                                      • Get Qt Extensions
                                      • Unsolved