http://blog.csdn.net/yanxiaoqing/article/details/7230660
1.添加阴影
self.layer.shadowOffset = CGSizeMake(-5, 3);
self.layer.shadowOpacity = 0.4;
self.layer.shadowColor = [UIColor blackColor].CGColor;
2.添加圆角
btn.layer.cornerRadius = 8;btn.layer.masksToBounds = YES;//使用边界来做遮罩
设置密文
[self.originalPwd setSecureTextEntry:YES];
原文：http://blog.csdn.net/oracleot/article/details/18750207