xcode7.3.1 Download
https://idmsa.apple.com/IDMSWebAuth/login?appIdKey= 891bd3417a7776362562d2197f89480a8547b108fd934911bcbea0110d07f757&path=%2fservices-account%2fdownload% 3fpath%3d%2fdeveloper_tools%2fxcode_7.3.1%2fxcode_7.3.1.dmg&rv=1 xcode8 fallback xcode7.3.1,xcode7.3.1 download
1) You can download multiple versions of Xcode, install on Mac, and choose to keep both.
(2) Your Xcode is downloaded and installed in the App Store. (I previously installed the xcode7.2 on my Mac directly from someone else, and then there was only one Xcode upgrade on the app Stroe to Xcode7.3.1,mac. To use the previously written code, in the xcode7.3.1 is actually better, but you download someone else's code to see, you want to use a low version of Xcode to open. )
A. You need to create a new folder in the application and drag the xcode7.3.1 into the folder.
B. Go to Google to download the version of Xcode you need and install it on your Mac.
Http://www.cnblogs.com/lelun/p/5551491.html An introduction to Apple's Official document Reading
http://blog.csdn.net/bao_libra/article/details/51364699 Gitbook Use
XCode 7.3.1 (DMG) Official direct