Unity 概念

本節(jié)介紹有關(guān) Unity Package Manager 功能的許多概念：

• 版本
• 清單
• 注冊表
• 包管理
• 包來源
• Package states and lifecycle
• Dependency and resolution
• Global cache

版本

Multiple versions of each package are available, marking changes to that package along its life cycle. Every time a developer updates the package, they give it a new version number. A change in package version tells you whether it contains a breaking change (major), new backward-compatible functionality (minor), or bug fixes only (patch), following Semantic Versioning.

要查看特定包可用的版本列表，請參閱查找特定版本。

清單

清單文件有兩種類型：

• Project manifests (manifest.json) store information that the Package Manager needs to locate and load the right packages, including a list of packages and versions declared as dependencies.
• Package manifests (package.json) store information about a specific package, and a list of packages and versions that the package requires.

這兩種文件都使用 JSON（JavaScript 對象表示法）語法。

注冊表

In the domain of Unity’s Package Manager, a package registry is a server that stores package contents and information (metadata) on each package version. Unity maintains a central registry of official packages that are available for distribution. By default, all projects use the official Unity package registry, but you can add addition al registries to store and distribute private packages or stage packages in development.

包管理

Unity Package Manager 是管理整個包系統(tǒng)的工具。此工具的主要任務(wù)包括：

• It communicates with the Unity package registry server and any additional registries you specify.
• 讀取您的項目清單并獲取包內(nèi)容和元數(shù)據(jù)。
• It installs, upgrades, and uninstalls packages, whether they are dependencies of the project or one of the installed packages.
• It imports Asset Store packages that you previously downloaded or purchased.
• It enables and disables Unity’s built-in packages.
• It displays information about every version of every package.
• 當(dāng)項目及其中的包需要多個包版本時解決沖突。

The Unity Package Manager installs samples, tools, and assets on a per-project basis, rather than installing them across all projects for a specific machine or device. It uses a global cache to store downloaded package metadata and contents. Once installed in a project, Unity treats package assets just like any other asset in the project, except that these assets are stored inside the package folder and are immutable. You can only permanently change content from Local and Embedded package sources.

包來源

來源描述了包的來源：

要編輯包的包清單，請參閱檢查包。

The Package Manager window displays a tag that corresponds to some of these sources. For more information, see Tags.