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According to the Qt docs I should be able to call:

Item replace(target, item, properties, operation)

Replaces one or more items on the stack with the specified item and operation, and optionally applies a set of properties on the item. The item can be an Item, Component, or a url. Returns the item that became current.

So if I were to enact:

stackView.replace(stackView.get(stackView.depth - 3), mycomponent)

I would expect the item, located at the stackView index 2 less than the largest index, to replace with mycomponent. However, this is not the case; it seems that index depth - 1 and depth - 2 and depth - 3 are popped off the stack, then an instance of mycomponent is added. How do I replace index of depth - 3 without losing the higher-stacked objects?

MVP: In the following code, if I push, push, push, then replace, I would expect Depth at onCompleted: 4 to be the value for Current Index: 1. Instead, I get Depth at onCompleted: 2

import QtQuick 2.9
import QtQuick.Window 2.2
import QtQuick.Controls 2.2

Window {
    visible: true
    width: 640
    height: 480
    id: window

    Component {
        id: mycomponent
        Row {
            spacing: 2
            Button {
                text: "Push"
                onClicked: push(mycomponent)
            }
            Button {
                text: "Pop"
                onClicked: pop()
            }
            Button {
                text: "Replace"
                onClicked: stackView.replace(stackView.get(stackView.depth - 3), mycomponent)
            }
            Text {
                text: "Current Index: " + (stackView.depth - 1)
            }
            Text {
                Component.onCompleted: text = "Depth at onCompleted: " + stackView.depth
            }
        }
    }

    StackView {
        id: stackView
        initialItem: mycomponent
    }
}
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Tyler M
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1 Answers1

1

Not that the described behaviour is correctly documented (second paragraph):

If the target argument is specified, all items down to the item will be replaced. If target is null, all items in the stack will be replaced. If not specified, only the top item will be replaced.

A solution may be to first pop 3 items (and store the two top items), push your new component and at the end push the stored items:

...
Button {
    text: "Replace"
    onClicked: {
        var item1 = stackView.pop();
        var item2 = stackView.pop();
        stackView.pop();
        stackView.push(mycomponent);
        stackView.push(item2);
        stackView.push(item1);            
    }
}
...
m7913d
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  • Thanks for catching that. Shame there isn't a built-in way to do this, but I'll just have to suffice – Tyler M Feb 18 '20 at 20:03
  • @TylerM The operation you want is not a stack(view) behaviour. It's somewhat strange that you want to modify a non-toplevel item as they represent a previous frame (which could normally be accessed using a back function). Note that you could extend `StackView` with your custom replace function as desired. – m7913d Feb 18 '20 at 20:56