我曾多次遇到过这个问题，对象是动态创建的，无论它们是用 QML 还是 C++ 创建的。对象在仍在使用时被删除，导致无缘无故的硬崩溃。这些对象一直被引用并成为其他对象的父对象，一直到根对象，所以我发现 QML 在它们的引用计数仍然高于零时删除这些对象很奇怪。

到目前为止，我找到的唯一解决方案是在 C++ 中创建对象并将所有权显式设置为 CPP，从而无法从 QML 中删除对象。

起初我认为这可能是育儿问题，因为我使用的是 QObject派生类，动态实例化的QML方法传递一个Item对于 parent ，而 QtObject甚至不带有父属性 - 它没有从 QObject 公开.

但后来我尝试使用 Qobject派生它公开并使用育儿，最后甚至尝试使用 Item只是为了确保对象的父对象正确，但这种行为仍然存在。

这是产生此行为的示例，不幸的是我无法将其压缩为单个源，因为 Component 的深层嵌套s 打破它:

// ObjMain.qml
Item {
    property ListModel list : ListModel { }
    Component.onCompleted: console.log("created " + this + " with parent " + parent)
    Component.onDestruction: console.log("deleted " + this)
}

// Uimain.qml
Item {
    id: main
    width: childrenRect.width
    height: childrenRect.height
    property Item object
    property bool expanded : true
    Loader {
        id: li
        x: 50
        y: 50
        active: expanded && object && object.list.count
        width: childrenRect.width
        height: childrenRect.height
        sourceComponent: listView
    }
    Component {
        id: listView
        ListView {
            width: contentItem.childrenRect.width
            height: contentItem.childrenRect.height
            model: object.list
            delegate: Item {
                id: p
                width: childrenRect.width
                height: childrenRect.height
                Component.onCompleted: Qt.createComponent("Uimain.qml").createObject(p, {"object" : o})
            }
        }
    }
    Rectangle {
        width: 50
        height: 50
        color: "red"

        MouseArea {
            anchors.fill: parent
            acceptedButtons: Qt.RightButton | Qt.LeftButton
            onClicked: {
                if (mouse.button == Qt.RightButton) {
                    expanded = !expanded
                } else {
                    object.list.append({ "o" : Qt.createComponent("ObjMain.qml").createObject(object) })
                }
            }
        }
    }
}

// main.qml

Window {
    visible: true
    width: 1280
    height: 720

    ObjMain {
        id: obj
    }

    Uimain {
        object: obj
    }
}

qml: created ObjMain_QMLTYPE_0(0x1e15bb8) with parent QQuickRootItem(0x1e15ca8)
qml: created ObjMain_QMLTYPE_0(0x1e5afc8) with parent ObjMain_QMLTYPE_0(0x1e15bb8)
qml: created ObjMain_QMLTYPE_0(0x1e30f58) with parent ObjMain_QMLTYPE_0(0x1e5afc8)
qml: deleted ObjMain_QMLTYPE_0(0x1e30f58)

The object is owned by JavaScript. When the object is returned to QML as the return value of a method call, QML will track it and delete it if there are no remaining JavaScript references to it and it has no QObject::parent()

最佳答案

I've encountered this problem on several occasions, with objects created dynamically, regardless of whether they were created in QML or C++

At first I assumed it may be an issue with parenting, since I was using QObject derived classes, and the QML method of dynamic instantiation passes an Item for a parent, whereas QtObject doesn't even come with a parent property - it is not exposed from QObject.

    delegate: Item {
        id: p
        width: childrenRect.width
        height: childrenRect.height
        Component.onCompleted: Qt.createComponent("Uimain.qml").createObject(p, {"object" : o})
    }

关于javascript - QML 垃圾收集删除仍在使用的对象，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33792876/