shift-shell/components/mobileshell/qml/components/GridView.qml

// SPDX-FileCopyrightText: 2022 Devin Lin <devin@kde.org>
// SPDX-License-Identifier: GPL-2.0-or-later

import QtQuick

import org.kde.plasma.extras as PlasmaExtras

GridView {
    id: root
    currentIndex: -1

    maximumFlickVelocity: 5000

    highlight: highlightComponent

    /** These function are called when the user tries to move the highlight outside the allowed surface by using arrow keys.
      * Useful to override the default behaviour of GridView (Pac-Man effect).
      */
    property var topEdgeCallback: null
    property var bottomEdgeCallback: null
    property var leftEdgeCallback: null
    property var rightEdgeCallback: null

    Keys.onPressed: event => {
        if (!currentItem) {
            return;
        }

        switch(event.key) {
            case Qt.Key_Left: {
                if (currentItem.x === 0
                    && leftEdgeCallback) {
                    leftEdgeCallback();
                }
                break;
            }
            case Qt.Key_Right: {
                if (indexAt(currentItem.x + cellWidth, currentItem.y) === -1
                    && rightEdgeCallback) {
                    rightEdgeCallback();
                }
                break;
            }
            case Qt.Key_Up: {
                if (currentItem.y === 0
                    && topEdgeCallback) {
                    topEdgeCallback();
                }
                break;
            }
            case Qt.Key_Down: {
                if (indexAt(currentItem.x, currentItem.y + cellHeight) === -1
                    && bottomEdgeCallback) {
                    bottomEdgeCallback();
                }
                break;
            }
        }
    }

    onActiveFocusChanged: {
        if (!activeFocus) {
            currentIndex = -1;
        }
    }

    onDraggingChanged: {
        if (dragging) {
            currentIndex = -1;
        }
    }

    Component {
        id: highlightComponent

        PlasmaExtras.Highlight {}
    }
}