解决问题

问题一

Xcode Run 后控制台红色警告：

Logging Error: Failed to initialize logging system. Log messages may be missing. If this issue persists, try setting IDEPreferLogStreaming=YES in the active scheme actions environment variables.

解决办法：

1. 点击Product > Scheme > Edit Scheme
2. 点击Arguments > Environment Variables 添加一个新的环境变量：
   Name：IDEPreferLogStreaming
   Value：YES