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How do I use QKeyEvent::key() even if window is not on top?

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  • mrjjM mrjj

    Hi
    it sounds like you want a global hot key
    https://msdn.microsoft.com/en-us/library/windows/desktop/ms646309(v=vs.85).aspx

    ? Offline
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    A Former User
    wrote on last edited by
    #7

    @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

    Hi
    it sounds like you want a global hot key
    https://msdn.microsoft.com/en-us/library/windows/desktop/ms646309(v=vs.85).aspx

    This looks like what I need. Thanks!
    Using this results in 2 error messages:

    - mainwindow.obj:-1: Fehler: LNK2019: unresolved external symbol __imp_RegisterHotKey referenced in function "public: void __cdecl MainWindow::timer(void)" (?timer@MainWindow@@QEAAXXZ)
    - debug\Code_Manager.exe:-1: Fehler: LNK1120: 1 unresolved externals
    

    I have tried checking whether the b-key is pressed:

        if (RegisterHotKey(NULL, 1, MOD_ALT | MOD_NOREPEAT, 0x42) == TRUE)  //0x42 is 'b'
        {
            ui->label->setText("true");
        }
        else
        {
            ui->label->setText("false");
        }
    
    mrjjM 1 Reply Last reply
    0
    • ? A Former User

      @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

      Hi
      it sounds like you want a global hot key
      https://msdn.microsoft.com/en-us/library/windows/desktop/ms646309(v=vs.85).aspx

      This looks like what I need. Thanks!
      Using this results in 2 error messages:

      - mainwindow.obj:-1: Fehler: LNK2019: unresolved external symbol __imp_RegisterHotKey referenced in function "public: void __cdecl MainWindow::timer(void)" (?timer@MainWindow@@QEAAXXZ)
      - debug\Code_Manager.exe:-1: Fehler: LNK1120: 1 unresolved externals
      

      I have tried checking whether the b-key is pressed:

          if (RegisterHotKey(NULL, 1, MOD_ALT | MOD_NOREPEAT, 0x42) == TRUE)  //0x42 is 'b'
          {
              ui->label->setText("true");
          }
          else
          {
              ui->label->setText("false");
          }
      
      mrjjM Offline
      mrjjM Offline
      mrjj
      Lifetime Qt Champion
      wrote on last edited by
      #8

      @SnuggleKat
      Hi
      The trick is always check which library to link to
      alt text

      Then add

      LIBS += -luser32

      to the .pro file.

      ? 1 Reply Last reply
      1
      • mrjjM mrjj

        @SnuggleKat
        Hi
        The trick is always check which library to link to
        alt text

        Then add

        LIBS += -luser32

        to the .pro file.

        ? Offline
        ? Offline
        A Former User
        wrote on last edited by
        #9

        @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

        LIBS += -luser32

        Thanks, but the problem still remains the same

        mrjjM 1 Reply Last reply
        0
        • ? A Former User

          @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

          LIBS += -luser32

          Thanks, but the problem still remains the same

          mrjjM Offline
          mrjjM Offline
          mrjj
          Lifetime Qt Champion
          wrote on last edited by mrjj
          #10

          @SnuggleKat
          Remember to run qmake after adding it
          Up in the build menu.

          ? 1 Reply Last reply
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          • mrjjM mrjj

            @SnuggleKat
            Remember to run qmake after adding it
            Up in the build menu.

            ? Offline
            ? Offline
            A Former User
            wrote on last edited by A Former User
            #11

            @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

            @SnuggleKat
            Remember to run qmake after adding it
            Up in the build menu.

            Thanks. I could compile it now. But the key value doesn't get checked. Could this issue be caused by the function being inside called up by a QTimer?
            If I put the function into the MainWindow::MainWindow the RegisterHotKey permanently returns TRUE

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            • mrjjM Offline
              mrjjM Offline
              mrjj
              Lifetime Qt Champion
              wrote on last edited by
              #12

              Hi
              You mean from a timer slot ?
              Should not make a difference however if you call it multiple times t without -
              UnregisterHotKey , it might considered it already registered and return false.
              you can show what GetLastError says in that case.

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              • mrjjM mrjj

                Hi
                You mean from a timer slot ?
                Should not make a difference however if you call it multiple times t without -
                UnregisterHotKey , it might considered it already registered and return false.
                you can show what GetLastError says in that case.

                ? Offline
                ? Offline
                A Former User
                wrote on last edited by
                #13

                @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                Hi
                You mean from a timer slot ?
                Should not make a difference however if you call it multiple times t without -
                UnregisterHotKey , it might considered it already registered and return false.
                you can show what GetLastError says in that case.

                Well, I got it working while the window is on top. But once I leave the window the button isn't registered anymore.

                RegisterHotKey(NULL, 0, MOD_IGNORE_ALL_MODIFIER, 0x42);
                    MSG msg;
                    GetMessage(&msg, 0, 0, 0);
                    PeekMessage(&msg, 0, 0, 0, 0x0001);
                
                    if(msg.wParam == 0x42)  //0x42 is 'b'
                    {
                        ui->label->setText("true");
                        *(cheat_array + 16) = 0x11;
                    }
                    else
                    {
                        ui->label->setText("false");
                        *(cheat_array + 16) = 0x00;
                    }
                
                1 Reply Last reply
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                • mrjjM Offline
                  mrjjM Offline
                  mrjj
                  Lifetime Qt Champion
                  wrote on last edited by
                  #14

                  Hi
                  You are using NULL for windows handle
                  Docs says
                  "If this parameter is NULL, WM_HOTKEY messages are posted to the message queue of the calling thread and must be processed in the message loop."

                  So i am wondering if it gets delivered by Qt when its not active.

                  Try to use its
                  (HWND)winId();
                  instead of NULL

                  ? 1 Reply Last reply
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                  • mrjjM mrjj

                    Hi
                    You are using NULL for windows handle
                    Docs says
                    "If this parameter is NULL, WM_HOTKEY messages are posted to the message queue of the calling thread and must be processed in the message loop."

                    So i am wondering if it gets delivered by Qt when its not active.

                    Try to use its
                    (HWND)winId();
                    instead of NULL

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                    A Former User
                    wrote on last edited by
                    #15

                    @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                    (HWND)winId();

                    no change

                    mrjjM 1 Reply Last reply
                    0
                    • ? A Former User

                      @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                      (HWND)winId();

                      no change

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

                      @SnuggleKat
                      Ok, i think its related to how the events are sent when windows not
                      in focus.

                      try use eventfilter for native events and see if it comes there when not in focus.
                      https://forum.qt.io/topic/32640/help-with-qabstractnativeeventfilter

                      you can also try this sample ( non qt) and see if that works in all cases.
                      Its uses native msg pump.

                      #include <stdio.h>
                      #include <tchar.h>
                      #include <windows.h>
                      
                      int main()
                      {       
                      	enum{ONE_KEYID = 1, TWO_KEYID = 2};
                      	RegisterHotKey(0, ONE_KEYID, MOD_NOREPEAT, 0x31); // register 1 key as hotkey
                      	RegisterHotKey(0, TWO_KEYID, MOD_NOREPEAT, 0x32); // register 2 key as hotkey
                      	MSG msg;
                      	while(GetMessage(&msg, 0, 0, 0))
                      	{
                      		PeekMessage(&msg, 0, 0, 0, 0x0001);
                      		switch(msg.message)
                      		{
                      		case WM_HOTKEY:
                      			if(msg.wParam == ONE_KEYID)
                      			{
                      				printf("1 Pressed");
                      			}
                      			else if(msg.wParam == TWO_KEYID)
                      			{
                      				printf("2 Pressed");
                      			}
                      		}
                      	}
                      	return 0;
                      }
                      
                      ? 1 Reply Last reply
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                      • mrjjM mrjj

                        @SnuggleKat
                        Ok, i think its related to how the events are sent when windows not
                        in focus.

                        try use eventfilter for native events and see if it comes there when not in focus.
                        https://forum.qt.io/topic/32640/help-with-qabstractnativeeventfilter

                        you can also try this sample ( non qt) and see if that works in all cases.
                        Its uses native msg pump.

                        #include <stdio.h>
                        #include <tchar.h>
                        #include <windows.h>
                        
                        int main()
                        {       
                        	enum{ONE_KEYID = 1, TWO_KEYID = 2};
                        	RegisterHotKey(0, ONE_KEYID, MOD_NOREPEAT, 0x31); // register 1 key as hotkey
                        	RegisterHotKey(0, TWO_KEYID, MOD_NOREPEAT, 0x32); // register 2 key as hotkey
                        	MSG msg;
                        	while(GetMessage(&msg, 0, 0, 0))
                        	{
                        		PeekMessage(&msg, 0, 0, 0, 0x0001);
                        		switch(msg.message)
                        		{
                        		case WM_HOTKEY:
                        			if(msg.wParam == ONE_KEYID)
                        			{
                        				printf("1 Pressed");
                        			}
                        			else if(msg.wParam == TWO_KEYID)
                        			{
                        				printf("2 Pressed");
                        			}
                        		}
                        	}
                        	return 0;
                        }
                        
                        ? Offline
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                        A Former User
                        wrote on last edited by
                        #17

                        @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                        @SnuggleKat
                        Ok, i think its related to how the events are sent when windows not
                        in focus.

                        try use eventfilter for native events and see if it comes there when not in focus.
                        https://forum.qt.io/topic/32640/help-with-qabstractnativeeventfilter

                        you can also try this sample ( non qt) and see if that works in all cases.
                        Its uses native msg pump.

                        #include <stdio.h>
                        #includ...
                        

                        My recent code update was based on this example.
                        Tried rebuilding it but didn't work either.

                        And I'm a little bit lost about the EventFilter thing..

                        mrjjM 1 Reply Last reply
                        0
                        • ? A Former User

                          @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                          @SnuggleKat
                          Ok, i think its related to how the events are sent when windows not
                          in focus.

                          try use eventfilter for native events and see if it comes there when not in focus.
                          https://forum.qt.io/topic/32640/help-with-qabstractnativeeventfilter

                          you can also try this sample ( non qt) and see if that works in all cases.
                          Its uses native msg pump.

                          #include <stdio.h>
                          #includ...
                          

                          My recent code update was based on this example.
                          Tried rebuilding it but didn't work either.

                          And I'm a little bit lost about the EventFilter thing..

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

                          @SnuggleKat

                          The link have sample of such eventfiler.
                          its not much code.

                          Its odd, the other sample didnt work as its windows less and have message pump.
                          But if u mix with a normal Qt it makes sense as the events are eating by QApplication then.

                          ? 1 Reply Last reply
                          0
                          • mrjjM mrjj

                            @SnuggleKat

                            The link have sample of such eventfiler.
                            its not much code.

                            Its odd, the other sample didnt work as its windows less and have message pump.
                            But if u mix with a normal Qt it makes sense as the events are eating by QApplication then.

                            ? Offline
                            ? Offline
                            A Former User
                            wrote on last edited by
                            #19

                            @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                            @SnuggleKat

                            The link have sample of such eventfiler.
                            its not much code.

                            Its odd, the other sample didnt work as its windows less and have message pump.
                            But if u mix with a normal Qt it makes sense as the events are eating by QApplication then.

                            I'm sorry, I can't get it to compile..

                            Could it be it doesn't work because the timer() function is a (public) slot?

                            mrjjM 1 Reply Last reply
                            0
                            • ? A Former User

                              @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                              @SnuggleKat

                              The link have sample of such eventfiler.
                              its not much code.

                              Its odd, the other sample didnt work as its windows less and have message pump.
                              But if u mix with a normal Qt it makes sense as the events are eating by QApplication then.

                              I'm sorry, I can't get it to compile..

                              Could it be it doesn't work because the timer() function is a (public) slot?

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

                              @SnuggleKat
                              A slot is just a normal c++ function.

                              But i dont understand why you need to call it in a timer.
                              You normally call it ONLY once to set up hot key.
                              Then reacts to WM_HOTKEY native event.
                              There would be no need of a timer.

                              Mixing Qt application and GetMessage() might have side effects.

                              This might help
                              http://amin-ahmadi.com/2015/11/14/how-to-use-system-wide-hotkeys-in-your-qt-application/

                              ? 1 Reply Last reply
                              0
                              • mrjjM mrjj

                                @SnuggleKat
                                A slot is just a normal c++ function.

                                But i dont understand why you need to call it in a timer.
                                You normally call it ONLY once to set up hot key.
                                Then reacts to WM_HOTKEY native event.
                                There would be no need of a timer.

                                Mixing Qt application and GetMessage() might have side effects.

                                This might help
                                http://amin-ahmadi.com/2015/11/14/how-to-use-system-wide-hotkeys-in-your-qt-application/

                                ? Offline
                                ? Offline
                                A Former User
                                wrote on last edited by
                                #21

                                @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                                @SnuggleKat
                                A slot is just a normal c++ function.

                                But i dont understand why you need to call it in a timer.
                                You normally call it ONLY once to set up hot key.
                                Then reacts to WM_HOTKEY native event.
                                There would be no need of a timer.

                                Mixing Qt application and GetMessage() might have side effects.

                                This might help
                                http://amin-ahmadi.com/2015/11/14/how-to-use-system-wide-hotkeys-in-your-qt-application/

                                I need it in a timer because it executes the codehandler as many times a second as defined by the user.
                                However, I could also transfer the key_value or key_code over to the timer

                                1 Reply Last reply
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                                • mrjjM Offline
                                  mrjjM Offline
                                  mrjj
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #22

                                  Ok. but try the sample i linked. it is using virtual override for native Event and it might work when app is not focused.
                                  Else an event filter on application seems the best way to grab WM_HOTKEY.

                                  ? 1 Reply Last reply
                                  0
                                  • mrjjM mrjj

                                    Ok. but try the sample i linked. it is using virtual override for native Event and it might work when app is not focused.
                                    Else an event filter on application seems the best way to grab WM_HOTKEY.

                                    ? Offline
                                    ? Offline
                                    A Former User
                                    wrote on last edited by
                                    #23

                                    @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                                    Ok. but try the sample i linked. it is using virtual override for native Event and it might work when app is not focused.
                                    Else an event filter on application seems the best way to grab WM_HOTKEY.

                                    Wow, it works, thank you!
                                    For some reason it makes the b-key not typing anything. is there are workaround?

                                    mrjjM 1 Reply Last reply
                                    0
                                    • ? A Former User

                                      @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                                      Ok. but try the sample i linked. it is using virtual override for native Event and it might work when app is not focused.
                                      Else an event filter on application seems the best way to grab WM_HOTKEY.

                                      Wow, it works, thank you!
                                      For some reason it makes the b-key not typing anything. is there are workaround?

                                      mrjjM Offline
                                      mrjjM Offline
                                      mrjj
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #24

                                      @SnuggleKat
                                      Super :)
                                      Some other app might have requested a hotkey on b.
                                      So if be is not sent to you. it means something else takes it.
                                      I think F12 also reserved and some others.

                                      ? 1 Reply Last reply
                                      0
                                      • mrjjM mrjj

                                        @SnuggleKat
                                        Super :)
                                        Some other app might have requested a hotkey on b.
                                        So if be is not sent to you. it means something else takes it.
                                        I think F12 also reserved and some others.

                                        ? Offline
                                        ? Offline
                                        A Former User
                                        wrote on last edited by
                                        #25

                                        @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                                        @SnuggleKat
                                        Super :)
                                        Some other app might have requested a hotkey on b.
                                        So if be is not sent to you. it means something else takes it.
                                        I think F12 also reserved and some others.

                                        I see!
                                        Well, it's not too bad though. I will upload a demo once I have made some more progress with my application

                                        mrjjM 1 Reply Last reply
                                        1
                                        • ? A Former User

                                          @mrjj said in How do I use QKeyEvent::key() even if window is not on top?:

                                          @SnuggleKat
                                          Super :)
                                          Some other app might have requested a hotkey on b.
                                          So if be is not sent to you. it means something else takes it.
                                          I think F12 also reserved and some others.

                                          I see!
                                          Well, it's not too bad though. I will upload a demo once I have made some more progress with my application

                                          mrjjM Offline
                                          mrjjM Offline
                                          mrjj
                                          Lifetime Qt Champion
                                          wrote on last edited by
                                          #26

                                          @SnuggleKat
                                          Super. please mark as solved if possible.
                                          You can always open other if later questions comes up.

                                          ? 1 Reply Last reply
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