使用Xcode管理代码时，会产生一些文件影响代码同步，比如UserInterfaceState.xcuserstate，需要设置忽略这些文件，在.gitignore文件中可以设置相应的忽略文件。
首先最好有一个空项目（因为已经上传的项目中的文件再设置.gitignore对已上传的文件无效），github、gitlab、码云都可以。将项目克隆到本地。
WX20180124-113612@2x.png
点击项目，按shift + command + .可以查看隐藏文件，再次可以隐藏。可以看到上图的.git文件。
cd到该项目，创建.gitignore文件。如下图：
WX20180124-114924@2x.png
打开.gitignore文件将下面代码粘贴进去。
#
# gitignore contributors: remember to update Global/Xcode.gitignore, Objective-C.gitignore & Swift.gitignore
## Build generated
build/
DerivedData/
## Various settings
*.xcuserstate
*.DS_Store
*.pbxuser
!default.pbxuser
*.mode1v3
!default.mode1v3
*.mode2v3
!default.mode2v3
*.perspectivev3
!default.perspectivev3
xcuserdata/
## Other
*.moved-aside
*.xccheckout
*.xcscmblueprint
## Obj-C/Swift specific
*.hmap
*.ipa
*.dSYM.zip
*.dSYM
# CocoaPods
#
# We recommend against adding the Pods directory to your .gitignore. However
# you should judge for yourself, the pros and cons are mentioned at:
# https://guides.cocoapods.org/using/using-cocoapods.html#should-i-check-the-pods-directory-into-source-control
#
# Pods/
# Carthage
#
# Add this line if you want to avoid checking in source code from Carthage dependencies.
# Carthage/Checkouts
Carthage/Build
# fastlane
#
# It is recommended to not store the screenshots in the git repo. Instead, use fastlane to re-generate the
# screenshots whenever they are needed.
# For more information about the recommended setup visit:
# https://docs.fastlane.tools/best-practices/source-control/#source-control
fastlane/report.xml
fastlane/Preview.html
fastlane/screenshots
fastlane/test_output
# Code Injection
#
# After new code Injection tools there's a generated folder /iOSInjectionProject
# https://github.com/johnno1962/injectionforxcode
iOSInjectionProject/
https://github.com/github/gitignore 源代码在这儿，只添加了忽略
*.xcuserstate
*.DS_Store
文件。
修改完保存，将修改后的项目上传就可以了。以后再提交代码就会忽略.xcuserstate和.DS_Store文件了。
如果项目不是空项目，建议先把完整项目备份好，删掉除.git文件夹以外的所有文件，然后上传。最后，再按上面的步骤走一遍，再把备份项目除去.git文件夹和.gitignore文件拷贝进去，再将代码上传就行了。
