如何在Swift中将UIColor转换为3/4/6/8位十六进制字符串? [英]How do I convert a UIColor to a 3/4/6/8 digits hexadecimal string in Swift?
如何在shoudPerformSegueWithIdentifier和Firebase中对用户进行身份验证? [英]How do I authenticate users in shoudPerformSegueWithIdentifier and Firebase?