Foundation

访问为你的应用定义基础层功能的基本数据类型，集合和操作系统服务。

概述

Foundation框架为App和其他框架提供了基础功能，包括数据存储和数据持久化，文本处理，日期和时间计算，排序和筛选以及联网功能。由Foundation定义的类，协议和数据类型在整个macOS，iOS，watchOS和tvOS SDK中通用。

主题

一、基本

● 数字，数据和基本值

Work with primitive values and other fundamental types used throughout Cocoa.

● 字符串和文本

Create and process strings of Unicode characters, use regular expressions to find patterns, and perform natural language analysis of text.

● 集合

Use arrays, dictionaries, sets, and specialized collections to store and iterate groups of objects or values.

● 日期和时间

Compare dates and times, and perform calendar and time zone calculations.

● 单位和尺寸（组件和大小）

Label numeric quantities with physical dimensions to allow locale-aware formatting and conversion between related units.

● 数据格式化

Convert numbers, dates, measurements, and other values to and from locale-aware string representations.

● 过滤和排序

Use predicates, expressions, and sort descriptors to examine elements in collections and other services.

二、应用支持

● 任务管理

管理你的应用程序的工作及其与系统服务（如“交接”和“快捷方式”）的交互方式。

● 资源

访问与你的应用捆绑在一起的资源和其他数据。

● 通知

Design patterns for broadcasting information and for subscribing to broadcasts.

● 应用扩展支持

管理应用扩展与其托管应用之间的交互。

● 错误和例外

Respond to problem situations in your interactions with APIs, and fine-tune your app for better debugging.

● 脚本支持

Allow users to control your app with AppleScript and other automation technologies, or run scripts from within your app.

三、文件和数据持久化

● 文件系统

Create, read, write, and examine files and folders in the file system.

● 档案和序列化

在属性列表、JSON和其他平面二进制表示形式之间来回转换对象和值。

● Preferences

Persistently store domain-scoped pieces of information used to configure your app.

● Spotlight

Search for files and other items on the local device, and index your app’s content for searching.

● iCloud

Manage files and key-value data that are automatically synchronized among a user’s iCloud devices.

四、网络

● URL加载系统

Interact with URLs and communicate with servers using standard Internet protocols.

● Bonjour

Advertise services for easy discovery on local networks, or discover services advertised by others.

五、Low-Level Utilities

● XPC

Manage secure interprocess communication.

● 对象运行时（Runtime）

Get low-level support for basic Objective-C features, Cocoa design patterns, and Swift integration.

● 进程和线程

Manage your app’s interaction with the host operating system and other processes, and implement low-level concurrency features.

● Streams, Sockets, and Ports

Use low-level Unix features to manage input and output among files, processes, and the network.

六、结构体

● struct NSOrderedCollectionDifferenceCalculationOptions

七、类

● class ListFormatter

● class NSOrderedCollectionChange

● class NSOrderedCollectionDifference

● class RelativeDateTimeFormatter

● class NSSecureUnarchiveFromDataTransformer

● class NSXPCCoder

● class URLSessionWebSocketTask

● class UnitInformationStorage

八、协议

● protocol ContiguousBytes

● protocol DataProtocol

● protocol MutableDataProtocol

● protocol URLSessionWebSocketDelegate

九、参考

● Foundation枚举

● Foundation常量

● Foundation数据类型

This document describes the data types and constants found in the Foundation framework.