slint/internal/compiler/widgets/material-base/listview.slint

// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-1.0 OR LicenseRef-Slint-commercial


import { ScrollView } from "scrollview.slint";
import { ListItem } from "components.slint";

// `ListView` is like a `Scrollview` but it should have a `for` element, and the content is automatically laid out in a list.
export component ListView inherits ScrollView {
    @children
}

component StandardListViewBase inherits ListView {
    private property <length> item-height: self.viewport-height / self.model.length;
    private property <length> current-item-y: self.viewport-y + current-item * item-height;

    in property <[StandardListViewItem]> model;
    in-out property <int> current-item: -1;

    for item[idx] in root.model : ListItem {
        selected: idx == root.current-item;
        text: item.text;

        clicked => {
            set-current-item(idx);
        }
    }

    public function set-current-item(index: int) {
        if(index < 0 || index >= model.length) {
            return;
        }

        current-item = index;

        if(current-item-y < 0) {
            self.viewport-y += 0 - current-item-y;
        }

        if(current-item-y + item-height > self.visible-height) {
            self.viewport-y -= current-item-y + item-height - self.visible-height;
        }
    }
}

// Like `ListView`, but with a default delegate, and a `model` property which is a model of type `StandardListViewItem`.
export component StandardListView inherits StandardListViewBase {
    FocusScope {
        key-pressed(event) => {
            if (event.text == Key.UpArrow) {
                root.set-current-item(root.current-item - 1);
                return accept;
            } else if (event.text == Key.DownArrow) {
                root.set-current-item(root.current-item + 1);
                return accept;
            }
            reject
        }
    }
}