plasma-framework/declarativeimports/plasmacomponents/qml/SectionScroller.qml

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/**Documentanted API
Inherits:
        Item

Imports:
        QtQuick 1.1
        org.kde.plasma.core
        SectionScroller.js

Description:
        It's similar to a ScrollBar or a ScrollDecorator.
        It's interactive and works on ListViews that have section.property set,
        so its contents are categorized.
        An indicator will say to what category the user scrolled to.

        Useful for things like address books or things sorted by date.
        Don't use with models too big (thousands of items) because implies
        loading all the items to memory, as well loses precision.

Properties:
        ListView listView:
        TODO needs info
**/

import QtQuick 1.1
import "private/SectionScroller.js" as Sections
import org.kde.plasma.core 0.1 as PlasmaCore

Item {
    id: root

    /**
     * The listview this scroll indicator will work on
     */
    property ListView listView

    onListViewChanged: {
        if (listView && listView.model)
            internal.initDirtyObserver();
    }

    Connections {
        target: listView
        onModelChanged: {
            if (listView && listView.model) {
                internal.initDirtyObserver()
            }
        }
    }

    width: 22
    Behavior on opacity {
        NumberAnimation {
            duration: 250
        }
    }

    anchors {
        right: listView.right
        top: listView.top
        bottom: listView.bottom
    }


    RangeModel {
        id: range

        minimumValue: 0
        maximumValue: Math.max(0, listView.contentHeight - listView.height)
        stepSize: 0
        //inverted: true
        positionAtMinimum: root.width*2
        positionAtMaximum: root.height - root.width*2
        value: listView.contentY
        onPositionChanged: sectionLabel.text = Sections.closestSection(position/listView.height)

    }

    ScrollBar {
        id: scrollBar
        flickableItem: listView
        anchors.fill: parent
        interactive: true
    }
    PlasmaCore.FrameSvgItem {
        imagePath: "widgets/tooltip"
        width: sectionLabel.paintedWidth + margins.left + margins.right
        height: sectionLabel.paintedHeight + margins.top + margins.bottom
        Label {
            id: sectionLabel
            font.pointSize: theme.defaultFont.pointSize*3
            x: parent.margins.left
            y: parent.margins.top
        }
        y: Math.min(root.height-height-scrollBar.width, Math.max(scrollBar.width, range.position - height/2))
        anchors {
            //verticalCenter: handle.verticalCenter
            right: parent.left
        }
        opacity: sectionLabel.text && scrollBar.pressed?1:0
        Behavior on opacity {
            NumberAnimation {
                duration: 250
            }
        }
    }


    QtObject {
        id: internal

        function initDirtyObserver() {
            Sections.initSectionData(listView);
            function dirtyObserver() {
                if (!internal.modelDirty) {
                    internal.modelDirty = true;
                    dirtyTimer.running = true;
                }
            }

            if (listView.model.countChanged)
                listView.model.countChanged.connect(dirtyObserver);

            if (listView.model.itemsChanged)
                listView.model.itemsChanged.connect(dirtyObserver);

            if (listView.model.itemsInserted)
                listView.model.itemsInserted.connect(dirtyObserver);

            if (listView.model.itemsMoved)
                listView.model.itemsMoved.connect(dirtyObserver);

            if (listView.model.itemsRemoved)
                listView.model.itemsRemoved.connect(dirtyObserver);

            sectionsRepeater.model = Sections._sections.length
        }
    }
}