slint/internal/compiler/widgets/common/combobox-base.slint

// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-1.1 OR LicenseRef-Slint-commercial

export component ComboBoxBase {
    in property <[string]> model;
    in property <bool> enabled <=> i-focus-scope.enabled;
    out property <bool> has-focus: i-focus-scope.has-focus && root.enabled;
    out property <bool> pressed <=> i-touch-area.pressed;
    out property <bool> has-hover: i-touch-area.has-hover;
    in-out property <int> current-index: 0;
    in-out property <string> current-value: root.model[root.current-index];

    callback selected(/* current-value */ string);
    callback show-popup();

    public function select(index: int) {
        if (!root.enabled) {
            return;
        }

        root.current-index = index;
        root.current-value = root.model[root.current-index];
        root.selected(root.current-value);
    }

    public function move-selection-up() {
        root.select(Math.max(root.current-index - 1, 0));
    }

    public function move-selection-down() {
        root.select(Math.min(root.current-index + 1, root.model.length - 1));
    }

    private property <length> scroll-delta: 2px;

    forward-focus: i-focus-scope;

    i-focus-scope := FocusScope {
        key-pressed(event) => {
            if (!self.enabled) {
                return reject;
            }

            if (event.text == Key.UpArrow) {
                root.move-selection-up();
                return accept;
            } else if (event.text == Key.DownArrow) {
                root.move-selection-down();
                return accept;
            } else if (event.text == Key.Return) {
                root.show-popup();
            }
            return reject;
        }

        i-touch-area := TouchArea {
            enabled: root.enabled;

            clicked => {
                root.focus();
                root.show-popup();
            }

            scroll-event(event) => {
                if (event.delta-y < -root.scroll-delta) {
                    root.move-selection-down();
                    return accept;
                }

                if (event.delta-y > root.scroll-delta) {
                    root.move-selection-up();
                    return accept;
                }

                reject
            }
        }
    }
}