Flutter Scaffold组件

Imagine you’re building a house, and each room represents a different part of your app’s user interface. In Flutter, these rooms are called widgets. Just like in a house where you have different furniture and decorations in each room, Flutter widgets are the visual and interactive elements that make up your app’s UI.

想象一下，你正在建造一座房子，每个房间都代表着应用用户界面的不同部分。在Flutter中，这些房间被称为widget。就像在房子里，每个房间都有不同的家具和装饰一样，Flutter widgets是构成应用程序UI的视觉和交互元素。

Widgets in Flutter are like building blocks that you can assemble to create your desired app design. They range from simple components like buttons and text fields to more complex layouts and animations. Think of widgets as the tools in your toolbox that allow you to craft beautiful and functional user interfaces.

Flutter中的小部件就像构建块，您可以组装它们来创建所需的应用程序设计。它们的范围从简单的组件(如按钮和文本字段)到更复杂的布局和动画。可以把小部件看作工具箱中的工具，它允许您创建美观且功能强大的用户界面。

What makes Flutter widgets exciting is their ability to be dynamic and responsive. Just like you can rearrange furniture or change the color of a room, widgets can adapt and respond to user interactions or changes in data. They give your app a lively and interactive feel, making it more engaging for users.

Flutter小部件令人兴奋的是它们的动态和响应能力。就像您可以重新安排家具或更改房间的颜色一样，小部件可以适应并响应用户交互或数据更改。它们会给你的应用带来活泼和互动的感觉，让它更吸引用户。

In Flutter, widgets follow a parent–child relationship, forming a hierarchical structure known as the widget tree. The root widget acts as the foundation, and each child widget builds upon it, creating a structured and organized UI. This tree-like structure allows you to easily manage and control the flow of information and actions within your app.

在Flutter中，小部件遵循父子关系，形成称为小部件树的分层结构。根小部件充当基础，每个子小部件都在其上构建，创建结构化和有组织的UI。这种树状结构允许您轻松管理和控制应用程序中的信息流和操作。

The beauty of Flutter widgets lies in their declarative nature. Rather than specifying the exact steps to create a UI, you describe what you want the UI to look like based on the current state of your app. Flutter takes care of the rest, automatically updating the UI to reflect any changes in the state.

Flutter小部件的美妙之处在于它们的声明性。而不是指定创建UI的具体步骤，你可以根据应用的当前状态描述你想要的UI外观。Flutter会自动更新UI以反映状态的任何变化。

As a Flutter developer, it’s essential to grasp the concept of widgets early on because they play a central role in the Flutter framework. With widgets, you can build visually appealing and responsive UIs that work seamlessly across multiple platforms.

作为一名Flutter开发人员，尽早掌握小部件的概念是非常重要的，因为它们在Flutter框架中扮演着核心角色。使用小部件，您可以构建视觉上吸引人且响应迅速的ui，这些ui可以跨多个平台无缝地工作。

This is a treasure trove of pre-built widgets that cater to various functionalities, designs, and user interactions. These widgets are categorized based on their specific purposes, making it easier for developers to find the right components for their app’s user interface. As the Flutter framework evolves, the widget catalog continues to expand, introducing new widgets to enhance the capabilities of your applications.

这是预先构建的小部件的宝库，可以满足各种功能、设计和用户交互。这些小部件根据其特定用途进行分类，使开发人员更容易为其应用程序的用户界面找到合适的组件。随着Flutter框架的发展，小部件目录也在不断扩展，引入了新的小部件来增强应用程序的功能。

As we dive deeper into Flutter, it’s essential to understand the basic building blocks that form the foundation of your app’s user interface. These basic widgets are the fundamental elements that enable you to create engaging and interactive layouts. In this section, we will explore the Basics widget catalog, which comprises widgets that are crucial for building user interfaces. These widgets serve as the starting point for crafting your app’s layout, structure, and interaction. Let’s take a closer look at some of the essential widgets within this category:

当我们深入到Flutter，它是必不可少的，以了解构成你的应用程序的用户界面的基础的基本构建块。这些基本的小部件是使您能够创建引人入胜的交互式布局的基本元素。在本节中，我们将探索Basics小部件目录，其中包含对于构建用户界面至关重要的小部件。这些小部件是制作应用程序布局、结构和交互的起点。

Imagine building a house. Before you add all the details and furnishings, you need a solid foundation. In Flutter, the Scaffold widget plays the role of the foundation for your app’s user interface. It provides the basic structure and layout that forms the backbone of your app’s screens.

想象一下建造一座房子。在你添加所有的细节和家具之前，你需要一个坚实的基础。在Flutter中，“Scaffold”小部件扮演着应用程序用户界面的基础角色。它提供了构成应用程序屏幕骨干的基本结构和布局。

The Scaffold widget acts as a container for various components that make up your app’s UI, such as the AppBar, body content, floating action button, and more. It brings together these elements to create a cohesive and organized user interface.

“Scaffold”小部件充当了组成应用程序UI的各种组件的容器，例如“AppBar”、body内容、浮动操作按钮等。它将这些元素结合在一起，以创建一个有凝聚力和有组织的用户界面。

Let’s break down the key components and features of the Scaffold widget:

让我们分解一下“脚手架”小部件的关键组件和特性:

See Figure 3.1: Sections marked in rectangles are scaffold components.

见图3.1:用矩形标记的部分为脚手架构件。

AppBar

The AppBar sits at the top of the screen and often contains the app’s title, navigation icons, and other actions. The Scaffold widget lets you easily include an AppBar as its top section.

“AppBar”位于屏幕顶部，通常包含应用程序的标题、导航图标和其他操作。“Scaffold”小部件允许您轻松地将“AppBar”作为其顶部部分。

Body Content

The main content of your screen resides within the body of the Scaffold. It can hold various widgets like text, images, lists, and even other layout structures. This is where you present the core information and interactions to your users.

屏幕的主要内容位于“Scaffold”的主体内。它可以容纳各种小部件，如文本、图像、列表，甚至其他布局结构。这是您向用户呈现核心信息和交互的地方。

Floating Action Button (FAB)

The Scaffold also provides a dedicated spot for the floating action button (FAB). This button is usually circular and prominently placed to trigger a primary action, such as adding a new item or initiating a key interaction in your app.

“脚手架”还为浮动动作按钮(FAB)提供了一个专用位置。这个按钮通常是圆形的，放在显眼的位置，用来触发一个主要动作，比如在你的应用中添加一个新项目或启动一个关键的交互。

Bottom Navigation Bar

If your app uses a bottom navigation bar to switch between different sections or views, the Scaffold supports integrating this navigation element as well. The bottom navigation bar is commonly used in apps with multiple screens or functionalities.

如果你的应用使用底部导航栏来在不同的部分或视图之间切换，脚手架也支持集成这个导航元素。底部导航栏通常用于具有多个屏幕或功能的应用程序。

Drawer

The Scaffold can also include a side drawer, accessible through a menu icon. The drawer provides additional navigation options or settings that users can access without leaving the current screen.

“脚手架”还可以包括一个侧面抽屉，通过菜单图标访问。抽屉提供了额外的导航选项或设置，用户可以在不离开当前屏幕的情况下访问。

Styling and Theming

Through the Scaffold widget, you can easily apply consistent styling and theming to your app’s UI elements. This ensures that your app maintains a cohesive look and feel across different screens and interactions. Don’t worry, later in this book, we will discuss styling and theming in depth.

通过“脚手架”小部件，你可以很容易地为应用程序的UI元素应用一致的样式和主题。这可以确保你的应用在不同的屏幕和交互中保持一致的外观和感觉。不要担心，在本书的后面，我们将深入讨论样式和主题。

原文地址：https://blog.csdn.net/qq_37703224/article/details/143032669

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