UIKeyboardTypeDefault, 默认键盘,支持所有字符
UIKeyboardTypeASCIICapable, 支持ASCII的默认键盘UIKeyboardTypeNumbersAndPunctuation, 标准电话键盘,支持+*#字符UIKeyboardTypeURL, URL键盘,支持.com按钮 只支持URL字符UIKeyboardTypeNumberPad, 数字键盘UIKeyboardTypePhonePad, 电话键盘UIKeyboardTypeNamePhonePad, 电话键盘,也支持输入人名UIKeyboardTypeEmailAddress, 用于输入电子 邮件地址的键盘UIKeyboardTypeDecimalPad, 数字键盘 有数字和小数点UIKeyboardTypeTwitter, 优化的键盘,方便输入@、#字符
UIKeyboardTypeAlphabet=UIKeyboardTypeASCIICapable,