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Property change notification

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  • X Offline
    X Offline
    xargs1
    wrote on last edited by xargs1
    #1

    I found something unexpected with onChange signals. If I have

    property int foo: 42
    onFooChanged: console.log(foo);
    

    This works as expected and I see nothing in the log unless foo is modified. But if I have

    readonly property int init: 42
    property int foo: init
    onFooChanged: console.log(foo);
    

    I will get a change notification in the log when the application starts. Is this expected behavior? Can it be changed?

    Qt 5.12.7

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    • 6thC6 Offline
      6thC6 Offline
      6thC
      wrote on last edited by
      #2

      Well, you could bind to changed after | onCompleted?

      I wouldn't get too hung up on just this if I found out unless it is affecting behaviour or functionality. I do act quite defensively to references to c++ null refs etc in qml and really act to cut rebinds away entierly.

      To assist me greatly do this, early in main I turn on qt.qml.binding.removal.info category logging. e.g:

      QLoggingCategory::setFilterRules(QStringLiteral("qt.qml.binding.removal.info  =true\n"));
      

      That way only the qt/qml objects produce rebind warning or if mine, only very determined rebinds, which I plan on eventually clearing those (currently just one) too.

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