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Is there any way to recognize if a data is changed from outside?

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  • D Offline
    D Offline
    developer_61
    wrote on last edited by developer_61
    #11

    @JonB sure it was the error that @mrjj say.
    Thank you so much guys you saved my day !

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    • D Offline
      D Offline
      developer_61
      wrote on last edited by developer_61
      #12

      I have another problem now:
      The function showmessage is called two times. Do you know why?
      @JonB @mrjj

      mrjjM 1 Reply Last reply
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      • D developer_61

        I have another problem now:
        The function showmessage is called two times. Do you know why?
        @JonB @mrjj

        mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by mrjj
        #13

        @developer_61

        Well it might be normal as it depends what you do to trigger it,
        Say first file is created and then closed. then open and written to.

        So it might be expected and how it should be :)

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        • D Offline
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          developer_61
          wrote on last edited by
          #14

          @mrjj I open the file change a letter and save it. After that the function is called two times.
          Really confusing. But what you mean the file is created and closed? I mean the file is already existing.

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          • D developer_61

            Hi !

            I have a QTComboBox and can choose datas there. The input of the data will shown on my UI.
            So what i want is:
            If i'm loading the data, and open the data outside from the UI (QT) i want to recognize if the data is changed from outside.
            So for example:

            1. example.docx is selected and loaded in the UI.
            2. example.docx is opened outside,changed and saved.
            3. The UI recognize that the data is changed and give a message for that.

            The data is shown by a QTreeView.

            Regards!

            J.HilkJ Online
            J.HilkJ Online
            J.Hilk
            Moderators
            wrote on last edited by
            #15

            @developer_61 if you simply want to check on start of your own application, if the file was modified, than you could use
            https://doc.qt.io/qt-5/qfileinfo.html#lastModified

            and check if the lastModified date correlates with your own last modification on it


            Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


            Q: What's that?
            A: It's blue light.
            Q: What does it do?
            A: It turns blue.

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            • D Offline
              D Offline
              developer_61
              wrote on last edited by
              #16

              @J-Hilk no i don't want to check it on start of my application. It has to been happen during the application. Evertything is working fine. Only the function showMessage is called two times.

              mrjjM 1 Reply Last reply
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              • D developer_61

                @J-Hilk no i don't want to check it on start of my application. It has to been happen during the application. Evertything is working fine. Only the function showMessage is called two times.

                mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by mrjj
                #17

                @developer_61

                Hi
                well both the file content and "last modified" flag is changed so i dont think its an error but
                simply how it works. QFileSystemWatcher sends 2 signals.

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                • D Offline
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                  developer_61
                  wrote on last edited by developer_61
                  #18

                  @mrjj and is there a way to avoid that?
                  maybe with a static or something like that ?

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                  • D Offline
                    D Offline
                    developer_61
                    wrote on last edited by
                    #19

                    does anybody have an idea?

                    mrjjM 1 Reply Last reply
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                    • D developer_61

                      does anybody have an idea?

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

                      @developer_61

                      Hi
                      No there is no way to avoid that as far as i know as its correctly reported as
                      the file do change twice. So QFileSystemWatcher is correct for it report it.

                      If its a huge issue for you, you could just use a timer and check "last modified" on the file
                      from time to time instead of using QFileSystemWatcher

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