https://guides.cocoapods.org/
CocoaPods使用
一、入门
1.Cocoapods简介
CocoaPods manages library dependencies for your Xcode projects.
The dependencies for your projects are specified in a single text file called a Podfile. CocoaPods will resolve dependencies between libraries, fetch the resulting source code, then link it together in an Xcode workspace to build your project.
Ultimately the goal is to improve discoverability of, and engagement in, third party open-source libraries by creating a more centralised ecosystem.
CocoaPods是用来管理Xcode工程中依赖的库，一般是第三方的公开库或者自己制作的私有库，比如AFNetworking
这些库是声明在一个叫Podfile的文件中的，CocoaPods会解析这个Podfile文件，将所有的库进行统一的管理，在Xcode workspace中编译到你的工程/项目。
2.基础操作
2.1.安装
CocoaPods是用的Ruby来构建的，macOS上已经提供了标准的Ruby了，建议使用最新版本的macOS，比如我现在是10.14.4
打开终端，输入
sudo gem install cocoapods
然后回车，然后可能会要求你输入开机密码，输入密码之后回车即可
2.2.更新
在终端中输入
sudo gem install cocoapods
回车后输入密码再次回车
下面这个是我本次更新在终端显示的日志
Fetching: cocoapods-core-1.6.2.gem (100%)
Successfully installed cocoapods-core-1.6.2
Fetching: cocoapods-1.6.2.gem (100%)
Successfully installed cocoapods-1.6.2
Parsing documentation for cocoapods-core-1.6.2
Installing ri documentation for cocoapods-core-1.6.2
Parsing documentation for cocoapods-1.6.2
Installing ri documentation for cocoapods-1.6.2
Done installing documentation for cocoapods-core, cocoapods after 5 seconds
2 gems installed
3.在Xcode工程中使用pods
3.1.在已有的项目中使用pods
我这里新建一个Xcode工程作为示例，你也可以先在新工程里试一试，掌握之后再在你的项目中使用
我在桌面上创建一个工程叫testCocoaPods
打开终端
cd到testCocoaPods目录下
cd Desktop/testCocoaPods/
输入
touch Podfile
会在文件夹中创建一个Podfile的文件，双击打开Podfile文件，粘贴如下代码并保存
target 'testCocoaPods' do
pod 'AFNetworking'
end
cd到testCocoaPods目录下，ls一下确认已经有Podfile文件
Podfile testCocoaPods testCocoaPods.xcodeproj
继续输入
pod install
回车后，终端中输入如下信息
Analyzing dependencies
Downloading dependencies
Installing AFNetworking (3.2.1)
Generating Pods project
Integrating client project
[!] Please close any current Xcode sessions and use `testCocoaPods.xcworkspace` for this project from now on.
Sending stats
Pod installation complete! There is 1 dependency from the Podfile and 1 total pod installed.
[!] Automatically assigning platform `ios` with version `12.2` on target `testCocoaPods` because no platform was specified. Please specify a platform for this target in your Podfile. See `https://guides.cocoapods.org/syntax/podfile.html#platform`.
同时查看testCocoaPods文件夹
多出了几个文件和文件夹
双击’testCocoaPods.xcworkspace’来打开工程，之后都将使用这个xcworkspace来进行开发，不再使用’testCocoaPods.xcodeproj’了
(如果刚才创建testCocoaPods.xcodeproj后xcode没有关闭这个项目记得先关闭再打开testCocoaPods.xcworkspace)
之后就可以在熟悉的AppDelegate.m、ViewController.m或者其他喜欢的地方
#import <AFNetworking.h>
3.2.使用pods创建新的项目
我们也可以用cocoapods创建一个新的项目
像往常一样在Xcode中创建一个新项，比如名字叫MyApp
在终端cd到MyApp目录
cd Desktop/MyApp/
pod init
这会在MyApp目录下创建Podfile文件，双击打开Podfile文件，可以看到
# Uncomment the next line to define a global platform for your project
# platform :ios, '9.0'
target 'MyApp' do
# Uncomment the next line if you're using Swift or would like to use dynamic frameworks
# use_frameworks!
# Pods for MyApp
end
打开第二行的注释，来制定平台和版本
platform :ios, '9.0'
target后面指定的就是工程名
do和end之间来添加cocoapod
比如AFNetworking，也可以指定AFNetworking的版本
pod 'AFNetworking', '~> 3.0'
编辑完Podfile文件之后就可以在终端里
pod install
Analyzing dependencies
Downloading dependencies
Installing AFNetworking (3.2.1)
Generating Pods project
Integrating client project
[!] Please close any current Xcode sessions and use `MyApp.xcworkspace` for this project from now on.
Sending stats
Pod installation complete! There is 1 dependency from the Podfile and 1 total pod installed.
可以看到使用的AFNetworking版本是3.2.1而不是3.0，这是因为
~> 3.0代表3.0到4.0之间(不包括4.0)的最高的一个版本
也可以使用其他的运算符
'> 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
或者
'~> 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.
关键词：cocoapods ruby 库管理 第三方库 lib .a .framework enter password 逻辑运算符