1.安装cocoapods 

sudo gem install cocoapods

出现：ERROR:  Could not find a valid gem 'cocospods’ (>= 0), here is why:

Unable to download data from http://ruby.taobao.org/ - bad response Not Found 404 (http://ruby.taobao.org/latest_specs.4.8.gz)

将http 替换成 https

1.gem sources --removehttp://ruby.taobao.org/

2.gem sources -ahttps://ruby.taobao.org/

3.查看源对不对

gem sources -l

然后又出现：  ERROR:While executing gem ... (Errno::EPERM)

Operation not permitted - /usr/bin/xcodeproj

之后输入下面代码解决：

sudo geminstall-n /usr/local/bincocoapods--pre