头文件

 @interface UITextField : UIControl <UITextInput, NSCoding> 

代理 UITextFieldDelegate

// 是否允许编辑模式 默认返回YES，进入编辑模式。NO不进入编辑模式
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField; 

// 开始编辑的时候 became first responder
- (void)textFieldDidBeginEditing:(UITextField *)textField;           

// 是否退出编辑模式
- (BOOL)textFieldShouldEndEditing:(UITextField *)textField; 

// 
- (void)textFieldDidEndEditing:(UITextField *)textField;

// 点击清除按钮是否清除 默认返回YES，返回NO不清除
- (BOOL)textFieldShouldClear:(UITextField *)textField

// 点击键盘上Return按钮时候调用
- (BOOL)textFieldShouldReturn:(UITextField *)textField

// 当输入任何字符时，代理调用该方法  string为输入的每一个
Characters

-(BOOL)textField:(UITextField *)field shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

通知

// 开始编辑
UIKIT_EXTERN NSString *const UITextFieldTextDidBeginEditingNotification;
// 结束编辑
UIKIT_EXTERN NSString *const UITextFieldTextDidEndEditingNotification;
// 内容改变 该方法多次调用
UIKIT_EXTERN NSString *const UITextFieldTextDidChangeNotification;

一些开发中比较重要的属性

@property (nullable, readwrite, strong) UIView *inputView; 

UntitleDAGA.gif

typedef NS_ENUM(NSInteger, UITextBorderStyle) {
    UITextBorderStyleNone,
    UITextBorderStyleLine,
    UITextBorderStyleBezel,
    UITextBorderStyleRoundedRect 默认  高度为固定30
};
@property(nonatomic)        UITextBorderStyle       borderStyle; 

@property(nullable, nonatomic,copy)   NSAttributedString     *attributedPlaceholder 
@property(nullable, nonatomic,copy)   NSAttributedString     *attributedText
@property(nullable, nonatomic,copy)   NSString               *placeholder; 
@property(null_resettable, nonatomic,strong)   UIColor     *tintColor
@property(nonatomic)        BOOL                    clearsOnBeginEditing;
@property(nonatomic)        UITextFieldViewMode  clearButtonMode;

@property(nullable, nonatomic,strong) UIView              *leftView;  
typedef NS_ENUM(NSInteger, UITextFieldViewMode) {
    UITextFieldViewModeNever,
    UITextFieldViewModeWhileEditing,
    UITextFieldViewModeUnlessEditing,
    UITextFieldViewModeAlways
};
@property(nonatomic)        UITextFieldViewMode  leftViewMode;  

@property(nullable, nonatomic,strong) UIView              *rightView; 
@property(nonatomic)        UITextFieldViewMode  rightViewMode;