＊＊＊＊＊＊＊首先是textField的三个常用属性＊＊＊＊＊
filed.autocapitalizationType=UITextAutocapitalizationTypeNone;//设置句首大写为None
filed.autocorrectionType=UITextAutocorrectionTypeNo;//设置不自动纠错
filed.secureTextEntry=YES;//设置不可视
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写UITextField时候总是会用到系统自带的keyboard.选用什么样的type，每次都会在这个地方卡壳。
这里把每个type对应的图片粘下来，便于记忆和查找。
typedefNS_ENUM(NSInteger, UIKeyboardType) {
UIKeyboardTypeDefault,// Default type for the current input method.（见下）
UIKeyboardTypeASCIICapable,// Displays a keyboard which can enter ASCII characters, non-ASCII keyboards remain active（见下）
UIKeyboardTypeNumbersAndPunctuation,// Numbers and assorted punctuation.（见下）
UIKeyboardTypeURL,// A type optimized for URL entry (shows . / .com prominently).（见下）
UIKeyboardTypeNumberPad,// A number pad (0-9). Suitable for PIN entry.（见下）
UIKeyboardTypePhonePad,// A phone pad (1-9, *, 0, #, with letters under the numbers).（见下）
UIKeyboardTypeNamePhonePad,// A type optimized for entering a person's name or phone number.（见下）
UIKeyboardTypeEmailAddress,// A type optimized for multiple email address entry (shows space @ . prominently).（见下）
UIKeyboardTypeDecimalPadNS_ENUM_AVAILABLE_IOS(4_1),// A number pad with a decimal point.（见下）
UIKeyboardTypeTwitterNS_ENUM_AVAILABLE_IOS(5_0),// A type optimized for twitter text entry (easy access to @ #)（见下）
UIKeyboardTypeWebSearchNS_ENUM_AVAILABLE_IOS(7_0),// A default keyboard type with URL-oriented addition (shows space . prominently).（见下）
UIKeyboardTypeAlphabet =UIKeyboardTypeASCIICapable,// Deprecated（见下）
};
