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  1. Qt
  2. QTBUG-93297

Implement QBindableSpy

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    Details

    • Type: Task
    • Status: In Progress
    • Priority: P3: Somewhat important
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Labels:
      None

      Description

      New bindable properties do not require signals. Because of that, checking how many times the value has actually changes becomes a little verbose.

      On the C++ side you need to implement something like this:

      int counter = 0;
      auto handler = object.bindableProperty().onValueChanged([&counter]() { ++counter; });
      Q_UNUSED(handler)

      And the situation becomes even more annoying, if one needs to do it on QML side. I could only solve it by introducing 2 extra properties:

      property real direction: testingSource.position.direction
      property int directionChangedCount:  0
      onDirectionChanged: {
          ++directionV1ChangedCount
      }
      

      Suggestion: let's implement a QBindableSpy that would behave very much like QSignalSpy, but do not require a signal.
      The actual API can be discussed, but as I see it now, it should be possible to do at least two things:

      • Query the total amount of changes (like QSignalSpy::count);
      • Query the individual value by index (like QSignalSpy::at(index)).

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        For Gerrit Dashboard: QTBUG-93297
        # Subject Branch Project Status CR V

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            People

            Assignee:
            fabiankosmale Fabian Kosmale
            Reporter:
            ivan.solovev Ivan Solovev
            PM Owner:
            Vladimir Minenko Vladimir Minenko
            RnD Owner:
            Alex Blasche Alex Blasche
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            Watchers:
            4 Start watching this issue

              Dates

              Created:
              Updated:

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