初始化

UITextField *tf = [[UITextField alloc] init];

typedef NS_ENUM(NSInteger, UITextBorderStyle) {//没有任何边框
    UITextBorderStyleNone,//线性边框
    UITextBorderStyleLine,//阴影效果边框
    UITextBorderStyleBezel,//原型效果边框
    UITextBorderStyleRoundedRect
};typedef NS_ENUM(NSInteger, UITextFieldViewMode) {//从不显示
    UITextFieldViewModeNever,//编辑的时候显示
    UITextFieldViewModeWhileEditing,//非编辑的时候显示
    UITextFieldViewModeUnlessEditing,//任何时候都显示
    UITextFieldViewModeAlways
};
//
//NS_CLASS_AVAILABLE_IOS(2_0) @interface UITextField : UIControl <UITextInput, NSCoding>
//
//获取和设置文字@property(nullable, nonatomic,copy)   NSString               *text;                 // default is nil
//获取和设置富文本@property(nullable, nonatomic,copy)   NSAttributedString     *attributedText NS_AVAILABLE_IOS(6_0); // default is nil
//文字的颜色@property(nullable, nonatomic,strong) UIColor                *textColor;            // default is nil. use opaque black
// 文字的font@property(nullable, nonatomic,strong) UIFont                 *font;                 // default is nil. use system font 12 pt
//对齐方式@property(nonatomic)        NSTextAlignment         textAlignment;        // default is NSLeftTextAlignment
//边框样式@property(nonatomic)        UITextBorderStyle       borderStyle;          // default is UITextBorderStyleNone. If set to UITextBorderStyleRoundedRect, custom background images are ignored.
//文字的大小，颜色等属性统一设置，影响较广泛，（全局）@property(nonatomic,copy)   NSDictionary<NSString *, id>           *defaultTextAttributes NS_AVAILABLE_IOS(7_0); // applies attributes to the full range of text. Unset attributes act like default values.
//
//占位文字@property(nullable, nonatomic,copy)   NSString               *placeholder;          // default is nil. string is drawn 70% gray
//富文本占位文字@property(nullable, nonatomic,copy)   NSAttributedString     *attributedPlaceholder NS_AVAILABLE_IOS(6_0); // default is nil
// 编辑完一次后，再次回来编辑会清空上次编辑的所有内容（为yes时）@property(nonatomic)        BOOL                    clearsOnBeginEditing; // default is NO which moves cursor to location clicked. if YES, all text cleared
//自动调整字体大小@property(nonatomic)        BOOL                    adjustsFontSizeToFitWidth; // default is NO. if YES, text will shrink to minFontSize along baseline
//字体最小值（自动调整时）@property(nonatomic)        CGFloat                 minimumFontSize;      // default is 0.0. actual min may be pinned to something readable. used if adjustsFontSizeToFitWidth is YES
//代理@property(nullable, nonatomic,weak)   id<UITextFieldDelegate> delegate;             // default is nil. weak reference
//背景图片（会拉伸）@property(nullable, nonatomic,strong) UIImage                *background;           // default is nil. draw in border rect. image should be stretchable
//不可用时背景图片@property(nullable, nonatomic,strong) UIImage                *disabledBackground;   // default is nil. ignored if background not set. image should be stretchable
//
//是否在编辑状态@property(nonatomic,readonly,getter=isEditing) BOOL editing;
//是否允许更改字符属性字典@property(nonatomic) BOOL allowsEditingTextAttributes NS_AVAILABLE_IOS(6_0); // default is NO. allows editing text attributes with style operations and pasting rich text
//设置属性字典@property(nullable, nonatomic,copy) NSDictionary<NSString *, id> *typingAttributes NS_AVAILABLE_IOS(6_0); // automatically resets when the selection changes
//
//// You can supply custom views which are displayed at the left or right
//// sides of the text field. Uses for such views could be to show an icon or
//// a button to operate on the text in the field in an application-defined
//// manner.
////
//// A very common use is to display a clear button on the right side of the
//// text field, and a standard clear button is provided.
//
//设置清除按钮的显示模式@property(nonatomic)        UITextFieldViewMode  clearButtonMode; // sets when the clear button shows up. default is UITextFieldViewModeNever
//
//设置输入框左边的view@property(nullable, nonatomic,strong) UIView              *leftView;        // e.g. magnifying glass
//设置输入框左视图的显示模式@property(nonatomic)        UITextFieldViewMode  leftViewMode;    // sets when the left view shows up. default is UITextFieldViewModeNever
//
  @property(nullable, nonatomic,strong) UIView              *rightView;       // e.g. bookmarks button@property(nonatomic)        UITextFieldViewMode  rightViewMode;   // sets when the right view shows up. default is UITextFieldViewModeNever
//
//// drawing and positioning overrides
//
  - (CGRect)borderRectForBounds:(CGRect)bounds;- (CGRect)textRectForBounds:(CGRect)bounds;- (CGRect)placeholderRectForBounds:(CGRect)bounds;- (CGRect)editingRectForBounds:(CGRect)bounds;- (CGRect)clearButtonRectForBounds:(CGRect)bounds;- (CGRect)leftViewRectForBounds:(CGRect)bounds;- (CGRect)rightViewRectForBounds:(CGRect)bounds;
//
  - (void)drawTextInRect:(CGRect)rect;- (void)drawPlaceholderInRect:(CGRect)rect;
//
//// Presented when object becomes first responder.  If set to nil, reverts to following responder chain.  If
//// set while first responder, will not take effect until reloadInputViews is called.
//设置输入框成为第一响应时弹出的视图和辅助视图（类似键盘）@property (nullable, readwrite, strong) UIView *inputView;
//键盘上的bar（辅助工具条）@property (nullable, readwrite, strong) UIView *inputAccessoryView;
//
//这个属性设置是否允许再次编辑时在内容中间插入内容@property(nonatomic) BOOL clearsOnInsertion NS_AVAILABLE_IOS(6_0); // defaults to NO. if YES, the selection UI is hidden, and inserting text will replace the contents of the field. changing the selection will automatically set this to NO.
//
  @end
//
  @interface UIView (UITextField)- (BOOL)endEditing:(BOOL)force;    // use to make the view or any subview that is the first responder resign (optionally force)@end
//
  @protocol UITextFieldDelegate <NSObject>
//
  @optional
//
//点击输入框时触发的方法，返回YES则可以进入编辑状态，NO则不能。- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField;        // return NO to disallow editing.
//开始编辑时调用的方法- (void)textFieldDidBeginEditing:(UITextField *)textField;           // became first responder
//将要结束编辑时调用的方法，返回YES则可以结束编辑状态，NO则不能- (BOOL)textFieldShouldEndEditing:(UITextField *)textField;          // return YES to allow editing to stop and to resign first responder status. NO to disallow the editing session to end
//结束编辑调用的方法- (void)textFieldDidEndEditing:(UITextField *)textField;             // may be called if forced even if shouldEndEditing returns NO (e.g. view removed from window) or endEditing:YES called
//
//输入字符时调用的方法- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string;   // return NO to not change text
//
//点击清除按钮时调用的函数，返回YES则可以清除，点击NO则不能清除- (BOOL)textFieldShouldClear:(UITextField *)textField;               // called when clear button pressed. return NO to ignore (no notifications)
//点击return键触发的函数- (BOOL)textFieldShouldReturn:(UITextField *)textField;              // called when 'return' key pressed. return NO to ignore.
//
  @end//
//NS_ASSUME_NONNULL_END

键盘代理

2016-03-18 07:54:42.866 UITextField[2479:169303] -[ViewController textFieldShouldBeginEditing:]
2016-03-18 07:54:42.880 UITextField[2479:169303] -[ViewController textFieldDidBeginEditing:]
2016-03-18 07:54:46.215 UITextField[2479:169303] -[ViewController textField:shouldChangeCharactersInRange:replacementString:]
2016-03-18 07:54:48.893 UITextField[2479:169303] -[ViewController textField:shouldChangeCharactersInRange:replacementString:]
2016-03-18 07:54:51.012 UITextField[2479:169303] -[ViewController textField:shouldChangeCharactersInRange:replacementString:]
2016-03-18 07:54:53.368 UITextField[2479:169303] -[ViewController textFieldShouldEndEditing:]
2016-03-18 07:54:53.375 UITextField[2479:169303] -[ViewController textFieldDidEndEditing:]