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// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:ui' show Color;
import 'framework.dart';
/// An interactive button within either material's [BottomNavigationBar]
/// or the iOS themed [CupertinoTabBar] with an icon and title.
/// This class is rarely used in isolation. It is typically embedded in one of
/// the bottom navigation widgets above.
/// See also:
/// * [BottomNavigationBar]
/// * <>
/// * [CupertinoTabBar]
/// * <>
class BottomNavigationBarItem {
/// Creates an item that is used with [BottomNavigationBar.items].
/// The argument [icon] should not be null and the argument [title] should not be null when used in a Material Design's [BottomNavigationBar].
const BottomNavigationBarItem({
@required this.icon,
Widget activeIcon,
}) : activeIcon = activeIcon ?? icon,
assert(icon != null);
/// The icon of the item.
/// Typically the icon is an [Icon] or an [ImageIcon] widget. If another type
/// of widget is provided then it should configure itself to match the current
/// [IconTheme] size and color.
/// If [activeIcon] is provided, this will only be displayed when the item is
/// not selected.
/// To make the bottom navigation bar more accessible, consider choosing an
/// icon with a stroked and filled version, such as [] and
/// [Icons.cloud_queue]. [icon] should be set to the stroked version and
/// [activeIcon] to the filled version.
/// If a particular icon doesn't have a stroked or filled version, then don't
/// pair unrelated icons. Instead, make sure to use a
/// [BottomNavigationBarType.shifting].
final Widget icon;
/// An alternative icon displayed when this bottom navigation item is
/// selected.
/// If this icon is not provided, the bottom navigation bar will display
/// [icon] in either state.
/// See also:
/// * [BottomNavigationBarItem.icon], for a description of how to pair icons.
final Widget activeIcon;
/// The title of the item. If the title is not provided only the icon will be shown when not used in a Material Design [BottomNavigationBar].
final Widget title;
/// The color of the background radial animation for material [BottomNavigationBar].
/// If the navigation bar's type is [BottomNavigationBarType.shifting], then
/// the entire bar is flooded with the [backgroundColor] when this item is
/// tapped. This will override [BottomNavigationBar.backgroundColor].
/// Not used for [CupertinoTabBar]. Control the invariant bar color directly
/// via [CupertinoTabBar.backgroundColor].
/// See also:
/// * [Icon.color] and [ImageIcon.color] to control the foreground color of
/// the icons themselves.
final Color backgroundColor;