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QListView & item movement

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  • A Offline
    A Offline
    asanka424
    wrote on last edited by
    #17

    this will enable drops in each item in your model. what you should do is disabling it like this

    item->setFlags(item->flags() ^ Qt::ItemIsDropEnabled)

    kshegunovK 1 Reply Last reply
    0
    • S Offline
      S Offline
      shahriar25
      wrote on last edited by
      #18

      Hi @asanka424 @SGaist
      I was able to set the item flags correctly but now I'm having problem with item changed signal.
      How do I know where was the Item (it's row) before it was moved? (I can set the item's data to hold the current row but isn't there a better way?)

      And also I was searching the QStandardItemModel's signals to find something useful and I found QStandardItemModel::rowsMoved(...) and QStandardItemModel::rowsAboutToBeMoved(...) and I tried them but they don't ge triggred when an item is moved. why is that?

      1 Reply Last reply
      0
      • A Offline
        A Offline
        asanka424
        wrote on last edited by
        #19

        You can try dataChanged signal but it won't identify moves explicitly.

        BTW does drag and drop work as you expected now?

        1 Reply Last reply
        0
        • S Offline
          S Offline
          shahriar25
          wrote on last edited by
          #20

          Hi @asanka424
          Yes it does. if it won't work then I will have to set the user data every time an item moves. but I think there has to be another way.

          1 Reply Last reply
          0
          • A asanka424

            this will enable drops in each item in your model. what you should do is disabling it like this

            item->setFlags(item->flags() ^ Qt::ItemIsDropEnabled)

            kshegunovK Offline
            kshegunovK Offline
            kshegunov
            Moderators
            wrote on last edited by kshegunov
            #21

            @asanka424

            what you should do is disabling it like this

            item->setFlags(item->flags() ^ Qt::ItemIsDropEnabled)
            

            Beware of such handling of flags!

            It's a very wrong way to do it. If the flag is not set you'll actually enable it, additionally it doesn't work with compound flags! Suppose you have (in binary) a = 010 and b = 110, then a ^ b == 100 which is very different from the expected 000.

            The proper way to remove a set of bits is to AND the inversion: a & ~b == 000
            /and this can be rigorously proven to be different from a ^ b if you expand the xor in the other basic operations a ^ b = (a & ~b) | (~a & b)/

            Read and abide by the Qt Code of Conduct

            A 1 Reply Last reply
            1
            • S Offline
              S Offline
              shahriar25
              wrote on last edited by
              #22

              Hi @kshegunov . Thank you for correcting that I cahnged my code.
              I tried the item changed flag and the data of item but it didn't work. I really don't know what to do

              kshegunovK 1 Reply Last reply
              0
              • S shahriar25

                Hi @kshegunov . Thank you for correcting that I cahnged my code.
                I tried the item changed flag and the data of item but it didn't work. I really don't know what to do

                kshegunovK Offline
                kshegunovK Offline
                kshegunov
                Moderators
                wrote on last edited by
                #23

                @shahriar25
                Well I don't know, I can't spot anything plainly wrong, although there isn't much code to begin with. However, this line:

                queueView->setDragEnabled(false);
                

                does look suspicious, have you removed it as it had been suggested, because it's not clear from your answer to @asanka424's question.

                Read and abide by the Qt Code of Conduct

                1 Reply Last reply
                0
                • kshegunovK kshegunov

                  @asanka424

                  what you should do is disabling it like this

                  item->setFlags(item->flags() ^ Qt::ItemIsDropEnabled)
                  

                  Beware of such handling of flags!

                  It's a very wrong way to do it. If the flag is not set you'll actually enable it, additionally it doesn't work with compound flags! Suppose you have (in binary) a = 010 and b = 110, then a ^ b == 100 which is very different from the expected 000.

                  The proper way to remove a set of bits is to AND the inversion: a & ~b == 000
                  /and this can be rigorously proven to be different from a ^ b if you expand the xor in the other basic operations a ^ b = (a & ~b) | (~a & b)/

                  A Offline
                  A Offline
                  asanka424
                  wrote on last edited by
                  #24

                  @kshegunov
                  Yes agree with you. I just replied for the context where I knew the flag is set.

                  1 Reply Last reply
                  0
                  • S Offline
                    S Offline
                    shahriar25
                    wrote on last edited by
                    #25

                    Hi @asanka424 @kshegunov
                    Sorry for replying late.
                    an interesting thing happened:
                    when I set the flags of the items to
                    queueModel->item(i)->setFlags(queueModel->item(i)->flags() & !Qt::ItemIsDropEnabled);
                    the items get disabled!
                    bot when I do:
                    queueModel->item(i)->setFlags(queueModel->item(i)->flags() ^ Qt::ItemIsDropEnabled);
                    the is no problem. I think I'm doing something wrong.

                    ANd I will try:
                    queueView->setDragEnabled(false);
                    and get back with a result. thank all of you for answering again. I love this from and the people who answer the questions

                    1 Reply Last reply
                    0
                    • S Offline
                      S Offline
                      shahriar25
                      wrote on last edited by
                      #26

                      Hi,
                      I tried this:
                      queueView->setDragEnabled(false);
                      and it didn't work.

                      this problem isn't fixable :( :(

                      1 Reply Last reply
                      0
                      • SGaistS Offline
                        SGaistS Offline
                        SGaist
                        Lifetime Qt Champion
                        wrote on last edited by
                        #27

                        One thing you can try: start by setting the view mode or don't set it at all since you are using the default mode.

                        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
                        • S Offline
                          S Offline
                          shahriar25
                          wrote on last edited by
                          #28

                          Hi,
                          I gave up moving the items by drag and droping them
                          Now I want to put move up and move down buttons
                          How can I move a selected index one item up or down?

                          1 Reply Last reply
                          0
                          • S Offline
                            S Offline
                            shahriar25
                            wrote on last edited by shahriar25
                            #29

                            Hi, I put two buttons for moving items up and down but when the buttons are pressed the listView goes out of focus and the selected items don't remain selected. how can I fix this?

                            and also how can I swap children of a QDomElement?

                            1 Reply Last reply
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