1、什么是 Podfile?

Podfile是描述一个或多个Xcode项目的目标的依赖关系的规范。该文件应该简单地命名为Podfile。

2、举例：

（1）very simple：

target 'MyApp' do
  use_frameworks!
  pod 'Alamofire', '~> 3.0'
end

（2）带官方库 & 私有库地址 & TestBundle：

source 'https://github.com/CocoaPods/Specs.git'  # 官方库地址
source 'https://github.com/Artsy/Specs.git'   # 私有库地址

platform :ios, '9.0'
inhibit_all_warnings!

target 'MyApp' do
  pod 'GoogleAnalytics', '~> 3.1'

  # Has its own copy of OCMock
  # and has access to GoogleAnalytics via the app
  # that hosts the test target

  target 'MyAppTests' do
    inherit! :search_paths
    pod 'OCMock', '~> 2.0.1'
  end
end

post_install do |installer|
  installer.pods_project.targets.each do |target|
    puts target.name
  end
end

（3）多个 Target 共享相同的 pods ：

• 第 1 种：定义 abstract_target：

# There are no targets called "Shows" in any Xcode projects
abstract_target 'Shows' do
  pod 'ShowsKit'
  pod 'Fabric'

  # Has its own copy of ShowsKit + ShowWebAuth
  target 'ShowsiOS' do
    # pod 'ShowWebAuth'
  end

  # Has its own copy of ShowsKit + ShowTVAuth
  target 'ShowsTV' do
    # pod 'ShowTVAuth'
  end
end

• 第 2 种：先 define ，后调用：

def common
  pod 'ShowsKit'
  pod 'Fabric'
end

target 'ShowsiOS' do
    common
end

target 'ShowsTV' do
    common
end

3、如何指定 pod 版本？

（1）不指定版本，则在每次 pod install 时，默认安装最新的：

pod 'SSZipArchive'

（2）指定特定的版本号：

pod 'Objection', '0.9'

（3）逻辑运算符指定版本号：

• '> 0.1' Any version higher than 0.1
• '>= 0.1' Version 0.1 and any higher version
• '< 0.1' Any version lower than 0.1
• '<= 0.1' Version 0.1 and any lower version

（4）~> 运算符指定版本号：

• '~> 0.1.2' Version 0.1.2 and the versions up to 0.2, not including 0.2 and higher
• '~> 0.1' Version 0.1 and the versions up to 1.0, not including 1.0 and higher
• '~> 0' Version 0 and higher, this is basically the same as not having it.

4、如何使用本地文件夹中的文件？

• 根文件夹下：

pod 'Alamofire', :path => '~/Documents/Alamofire'

• 与本工程在同一个文件夹下的某一个文件夹文件 & 指定 Git 分支：

pod 'DolphinX',:path => '../DolphinX',:branch => 'develop'

5、From a podspec in the root of a library repo.：

• master branch：

pod 'Alamofire', :git => 'https://github.com/Alamofire/Alamofire.git'

• To use a different branch of the repo：

pod 'Alamofire', :git => 'https://github.com/Alamofire/Alamofire.git', :branch => 'dev'

• To use a tag of the repo：

pod 'Alamofire', :git => 'https://github.com/Alamofire/Alamofire.git', :tag => '3.1.1'

• Or specify a commit：

pod 'Alamofire', :git => 'https://github.com/Alamofire/Alamofire.git', :commit => '0f506b1c45'