UITextField 输入框的基本使用(创建显示,回收键盘)

typedef NS_ENUM(NSInteger, UITextBorderStyle) {

    UITextBorderStyleNone,   //没有边线框

    UITextBorderStyleLine,   //方框

    UITextBorderStyleBezel,  //略像winXP的输入框

    UITextBorderStyleRoundedRect  //圆角矩形，此风格设置背景图片无效

};

typedef NS_ENUM(NSInteger, UITextFieldViewMode) {

    UITextFieldViewModeNever,           //从不

    UITextFieldViewModeWhileEditing,    //当编辑的时候有效

    UITextFieldViewModeUnlessEditing,   //除了编辑的时候，其他时候有效

    UITextFieldViewModeAlways           //总是有效

};

@interface UITextField : UIControl <UITextInput, NSCoding> 

@property(nonatomic,copy)   NSString               *text;                 //textField中的文本 default is nil

@property(nonatomic,copy)   NSAttributedString     *attributedText NS_AVAILABLE_IOS(6_0); // default is nil

@property(nonatomic,retain) UIColor                *textColor;            //textField中文本的颜色 default is nil. use opaque black

@property(nonatomic,retain) UIFont                 *font;                 //textField中文本的格式 default is nil. use system font 12 pt

@property(nonatomic)        NSTextAlignment         textAlignment;        //textField中文本的对齐方式  default is NSLeftTextAlignment

@property(nonatomic)        UITextBorderStyle       borderStyle;          //textField的边框风格  default is UITextBorderStyleNone. If set to UITextBorderStyleRoundedRect, custom background images are ignored.

@property(nonatomic,copy)   NSDictionary           *defaultTextAttributes NS_AVAILABLE_IOS(7_0); // applies attributes to the full range of text. Unset attributes act like default values.

@property(nonatomic,copy)   NSString               *placeholder;          //textField为空时，默认的灰色提示文本   default is nil. string is drawn 70% gray

@property(nonatomic,copy)   NSAttributedString     *attributedPlaceholder NS_AVAILABLE_IOS(6_0); // default is nil

@property(nonatomic)        BOOL                    clearsOnBeginEditing; //开始输入时清空原有输入内容default is NO which moves cursor to location clicked. if YES, all text cleared

@property(nonatomic)        BOOL                    adjustsFontSizeToFitWidth; //用处不大，当文本很长时，文本适应输入框宽度而缩小 default is NO. if YES, text will shrink to minFontSize along baseline

@property(nonatomic)        CGFloat                 minimumFontSize;      //用处不大 default is 0.0. actual min may be pinned to something readable. used if adjustsFontSizeToFitWidth is YES

@property(nonatomic,assign) id<UITextFieldDelegate> delegate;             // default is nil. weak reference

@property(nonatomic,retain) UIImage                *background;           //输入框enable = YES的时候(需要边框类型设置为UITextBorderStyleNone)default is nil. draw in border rect. image should be stretchable

@property(nonatomic,retain) UIImage                *disabledBackground;   //输入框的enable = NO时显示的图片(需要设置background) default is nil. ignored if background not set. image should be stretchable

@property(nonatomic,readonly,getter=isEditing) BOOL editing;  //获取当前textField是否处于编辑状态

@property(nonatomic) BOOL allowsEditingTextAttributes NS_AVAILABLE_IOS(6_0); // default is NO. allows editing text attributes with style operations and pasting rich text

@property(nonatomic,copy) NSDictionary *typingAttributes NS_AVAILABLE_IOS(6_0); // automatically resets when the selection changes

@property(nonatomic)        UITextFieldViewMode  clearButtonMode; //设置右侧清空按钮显示的时间场合 sets when the clear button shows up. default is UITextFieldViewModeNever

@property(nonatomic,retain) UIView              *leftView;        // e.g. magnifying glass

@property(nonatomic)        UITextFieldViewMode  leftViewMode;    //设置什么状态时显示左图片 sets when the left view shows up. default is UITextFieldViewModeNever

@property(nonatomic,retain) UIView              *rightView;       // e.g. bookmarks button

@property(nonatomic)        UITextFieldViewMode  rightViewMode;   //设置什么状态时显示右图片 sets when the right view shows up. default is UITextFieldViewModeNever

// drawing and positioning overrides

//这些方法用于自定制时进行重写方法，以实现绘制和放置自定制的textField的不同的属性的位置。这些函数的返回值就相当于一些参数，用于系统内部在实现生成控件时调用。

- (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.

@property (readwrite, retain) UIView *inputView;        //可以用View替换点击TextField弹出的键盘     

@property (readwrite, retain) UIView *inputAccessoryView;  //键盘上方会出现一个View作为输入的辅助view

@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;    //可以用于实现退出编辑，比如添加到触摸或手势中 use to make the view or any subview that is the first responder resign (optionally force)

@end

@protocol UITextFieldDelegate <NSObject> //提供用户在文本框不同状态时自定义执行的方法

UIKIT_EXTERN NSString *const UITextFieldTextDidBeginEditingNotification;

UIKIT_EXTERN NSString *const UITextFieldTextDidEndEditingNotification;

UIKIT_EXTERN NSString *const UITextFieldTextDidChangeNotification;