How to animate scroll in a QML ScrollView?

问题

How can I animate scrolling in a QML ScrollView?

I've tried a Behavior on the contentItem.contentY, but that isn't working.

回答1:

With Qt Quick Controls 1

You just have to animate the value changes on the property flickableItem.contentY.

A quick example:

Item {
    anchors.fill: parent
    ColumnLayout {
        anchors.fill: parent
        Button {
            id: btn
            onClicked: scroll.scrollTo(scroll.flickableItem.contentY + 100)
        }

        ScrollView {
            id: scroll
            function scrollTo(y) {
                scrollAnimation.to = y
                scrollAnimation.start()
            }

            NumberAnimation on flickableItem.contentY {
                id: scrollAnimation
                duration: 1000
            }
            contentItem: Column {
                Repeater {
                        model: 30
                        Rectangle {
                            width: 100; height: 40
                            border.width: 1
                            color: "yellow"
                        }
                    }
            }
        }
    }
}

When you click on the button, it will scroll by 100 px with a smooth jump.

With Qt Quick Controls 2

The flickableItem.contentY isn't available anymore. The simpliest way to do the same thing in Qt Quick Controls 2 is to animate the position of the ScrollBar.

Notice that the position of QScrollBar is in percent (expressed between 0 and 1), not in pixels.

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")
    ScrollView {
        id: scroll
        width: 200
        height: 200
        clip: true
        function scrollTo(y) {
            scrollAnimation.to = y
            scrollAnimation.start()
        }
        ScrollBar.vertical: ScrollBar {
            id: test
            parent: scroll
            x: scroll.mirrored ? 0 : scroll.width - width
            y: scroll.topPadding
            height: scroll.availableHeight
            active: scroll.ScrollBar.horizontal.active
            policy: ScrollBar.AlwaysOn

            NumberAnimation on position {
                id: scrollAnimation
                duration: 1000
            }
        }
        ListView {
            model: 20
            delegate: ItemDelegate {
                text: "Item " + index
            }
        }
    }
    Button {
        id: btn
        anchors.top: scroll.bottom
        onClicked: scroll.scrollTo(test.position + 0.1)
    }
}

When you click on the button, it will scroll by 10% of the height.

来源：https://stackoverflow.com/questions/56682077/how-to-animate-scroll-in-a-qml-scrollview