In many applications, user input is a key element. However, as the complexity of the app and the potential input options increase, providing a smooth and efficient input experience becomes crucial. The Autocomplete widget in Flutter addresses this challenge by offering a way to suggest and complete user input based on a predefined set of options.
在许多应用程序中，用户输入是一个关键元素。然而，随着应用的复杂性和潜在输入选项的增加，提供流畅和高效的输入体验变得至关重要。Flutter中的“自动完成”小部件通过提供一种基于预定义选项集的建议和完成用户输入的方法，解决了这一挑战。
See Figure 3.7: A basic app with Autocomplete widget
参见图3.7:一个带有自动完成小部件的基本应用程序
Functionality
The Autocomplete widget is designed to work with text input fields. As the user types, the widget presents a dropdown-like menu of suggested completions based on the entered text. This feature is particularly useful when dealing with a long list of items or complex input patterns. Users can select a suggestion from the dropdown, which can be directly inserted into the input field, saving them time and reducing the risk of errors.
“自动完成”小部件设计用于处理文本输入字段。当用户输入时，小部件根据输入的文本显示一个类似下拉菜单的建议补全。当处理一长串项目或复杂的输入模式时，这个特性特别有用。用户可以从下拉框中选择建议，直接插入到输入框中，节省了时间，降低了出错的风险。
Usage
Implementing the Autocomplete widget involves providing a list of possible completions (options) and a callback function that filters and sorts these options based on the current input. You can customize the appearance of the suggestions list, control the maximum number of suggestions shown, and determine how the selected completion is displayed in the input field.
实现“自动完成”小部件包括提供一个可能完成的列表(“选项”)和一个回调函数，该函数根据当前输入对这些选项进行过滤和排序。您可以自定义建议列表的外观，控制显示的建议的最大数量，并确定如何在输入字段中显示所选的补全。
User Experience
The Autocomplete widget enhances the user experience by offering real-time suggestions that help users find the right input quickly. It’s particularly useful when dealing with data that users might not be familiar with, such as selecting a location from a list of cities, choosing a product from an inventory, or picking a contact from an address book.
“自动补全”小部件通过提供实时建议来增强用户体验，帮助用户快速找到正确的输入。在处理用户可能不熟悉的数据时，例如从城市列表中选择位置，从库存中选择产品，或从地址簿中选择联系人，这一点特别有用。
Accessibility
When implementing the Autocomplete widget, consider accessibility. Ensure that the suggestions list is navigable using keyboard controls, and provide appropriate labels or descriptions for the suggestions using the Semantics widget.
在实现“自动完成”小部件时，要考虑可访问性。确保建议列表可以使用键盘控件进行导航，并使用“Semantics”小部件为建议提供适当的标签或描述。
Customization
While the basic functionality of the Autocomplete widget serves a wide range of scenarios, you can also customize its behavior and appearance. For instance, you can control how the suggestions are sorted, highlight matches in the suggestions, and even provide your own custom widget for each suggestion.
虽然“自动完成”小部件的基本功能适用于各种场景，但您也可以自定义其行为和外观。例如，您可以控制建议的排序方式，突出显示建议中的匹配项，甚至为每个建议提供您自己的自定义小部件。
Practical Examples
Think of an app that allows users to search for books by entering the author’s name. As the user types, the Autocomplete widget can offer a list of author names that match the input, helping the user quickly find the desired author without typing the full name.
设想一个应用程序，允许用户通过输入作者的名字来搜索书籍。当用户输入时，“自动完成”小部件可以提供与输入匹配的作者姓名列表，帮助用户快速找到所需的作者，而无需输入全名。
The Autocomplete widget simplifies user input by providing realtime suggestions based on a predefined list of options. With the use of this widget, you can improve the accuracy and efficiency of data entry in your app, resulting in a more user-friendly and intuitive experience. As you continue exploring this chapter, you’ll gain hands-on experience with the Autocomplete widget and discover its potential for enhancing your app’s input capabilities.
“自动完成”小部件通过基于预定义的选项列表提供实时建议来简化用户输入。通过使用这个小部件，您可以提高应用程序中数据输入的准确性和效率，从而获得更加用户友好和直观的体验。当你继续探索本章时，你将获得“自动完成”小部件的实践经验，并发现其增强应用程序输入功能的潜力。