qml - プロパティを QML 要素に動的に追加するにはどうすればよいですか?

Question

プロパティを QML 要素に動的に追加したい:

Item {
 id: dynamicProperty;
 property int first;


 Component.onCompleted: {
  /* once this block of code is executed, i want to add
     property int second; property bool third; property variant fourth;
  */
 }

}

上記のタスクを達成する方法はありますか。

Answer 1

I don't think QML was designed to support dynamic property creation.

Depending on your use-case this could be worked around with "script instances" (I made up the term). Basically each QML Component instantiation that import script which doesn't have .pragma library statement will work with its own copy of globals declared in the script.

For example you can look at PageStack (qt-components) code.

There is import "PageStack.js" as Engine statement, and it later referred to call functions that uses global variables like if it was instance variables.

If you looking for a way to add members to your QML Component and don't need property change notifications, "script instances" would do just fine.

Answer 2

次のようにできるかもしれません：

Item {
    id: dynamicProperty;
    property int first;
    property var extraData;

    Component.onCompleted: {
        /* once this block of code is executed, i want to add
           property int second; property bool third; property variant fourth;
        */
        var data;
        data["second"] = 0;
        data["third"] = false;
        ...
        extraData = data;
   }
}