1.初始化控件 (文本輸入控件)

特殊初始化

 _evtxf = ({
        UITextField *ettxf = [[UITextField alloc]init];
        .
        .
        [self.view addSubview:ettxf];
        ettxf;
});

2.設(shè)置基本屬性及用法

frame:設(shè)置UITextField的顯示起點坐標(biāo)（x,y）和寬高(width,height)

 ettxf.frame = CGRectMake(<#x起點#>, <#y起點#>, <#寬度#>,<#高度#>);

placeholder:當(dāng)輸入框沒有內(nèi)容時，水印提示提示內(nèi)容為"水印提示"

ettxf.placeholder = @"水印提示";

//補充：設(shè)置placeholder的顏色枝哄，其中的_placeholderLabel.textColor是系統(tǒng)自帶的瓮钥，可以直接使用
[ettxf setValue:[UIColor grayColor] forKeyPath:@"_placeholderLabel.textColor"]; 

//textColor:設(shè)置輸入文字字體顏色
ettxf.textColor = [UIColor redColor];
//設(shè)置光標(biāo)顏色  
[ettxf setTintColor:[UIColor whiteColor]];  

backgroundColor:設(shè)置輸入框的背景顏色招拙，此時設(shè)置為白色如果使用了自定義的背景圖片邊框會被忽略掉（建議：backgroundColor與background別同時使用）

ettxf.backgroundColor = [UIColor whiteColor];

background設(shè)置背景

ettxf.borderStyle = UITextBorderStyleNone;//先要去除邊框樣式(類似UIButtonCustom)
ettxf.background = [UIImage imageNamed:@"iconfont-Mask.png"];

font:設(shè)置輸入框內(nèi)容的字體樣式和大小

ettxf.font = [UIFont systemFontOfSize:15];

secureTextEntry:密碼形式輸入

ettxf.secureTextEntry = YES;

clearsOnBeginEditing:再次編輯就清空

ettxf.clearsOnBeginEditing = YES;

adjustsFontSizeToFitWidth:當(dāng)文字超出文本框?qū)挾葧r署照，自動調(diào)整文字大小

ettxf.adjustsFontSizeToFitWidth = YES;

minimumFontSize:最小可縮小的字號和adjustsFontSizeToFitWidth一起使用

ettxf.minimumFontSize = 20;

textAlignment:內(nèi)容對齊方式（水平對齊 ）

ettxf.textAlignment = UITextAlignmentLeft;

contentVerticalAlignment: 垂直對齊 (該屬性不起作用禽作，待后續(xù)研究)

ettxf.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;

borderStyle:設(shè)置邊框樣式，只有設(shè)置了才會顯示邊框樣式

ettxf.borderStyle = UITextBorderStyleRoundedRect;

clearButtonMode:輸入框中是否有個叉號岸裙，在什么時候顯示，用于一次性刪除輸入框中的內(nèi)容

ettxf.clearButtonMode = UITextFieldViewModeAlways;

keyboardType:設(shè)置鍵盤的樣式

ettxf.keyboardType = UIKeyboardTypeDefault;

/************************************UIKeyboardType************************************/
        UIKeyboardTypeDefault           ;   //系統(tǒng)默認(rèn)的虛擬鍵盤
        UIKeyboardTypeASCIICapable      ;   //顯示英文字母的虛擬鍵盤
        UIKeyboardTypeNumbersAndPunctuation;//顯示數(shù)字＋標(biāo)點的虛擬鍵盤
        UIKeyboardTypeURL               ;   //URL鍵盤速缆，支持.com按鈕只支持URL字符
        UIKeyboardTypeNumberPad         ;   //數(shù)字鍵盤
        UIKeyboardTypePhonePad          ;   //顯示便于撥號呼叫的電話鍵盤
        UIKeyboardTypeNamePhonePad      ;   //電話鍵盤降允，也支持輸入人名
        UIKeyboardTypeEmailAddress      ;   //用于輸入電子郵件地址的鍵盤
        UIKeyboardTypeDecimalPad        ;   //數(shù)字＋小數(shù)點的數(shù)字鍵盤
        UIKeyboardTypeTwitter           ;   //優(yōu)化的鍵盤，方便輸入@艺糜、#字符
/**************************************************************************************/

autocorrectionType:是否糾錯

ettxf.autocorrectionType = UITextAutocorrectionTypeNo;

/***************************UITextAutocorrectionType***********************************/
        UITextAutocorrectionTypeDefault ;   //默認(rèn)
        UITextAutocorrectionTypeNo      ;   //不自動糾錯
        UITextAutocorrectionTypeYes     ;   //自動糾錯
/**************************************************************************************/

autocapitalizationType:首字母是否大寫

ettxf.autocapitalizationType = UITextAutocapitalizationTypeNone;

/***************************UITextAutocapitalizationType******************************/
        UITextAutocapitalizationTypeNone         ;//不自動大寫
        UITextAutocapitalizationTypeWords        ;//單詞首字母大寫
        UITextAutocapitalizationTypeSentences    ;//句子的首字母大寫
        UITextAutocapitalizationTypeAllCharacters;//所有字母都大寫
/**************************************************************************************/

returnKeyType:return鍵變成什么鍵

ettxf.returnKeyType =UIReturnKeyDone;

/****************************UIReturnKeyType******************************************/
        UIReturnKeyDefault      ;//默認(rèn)灰色按鈕剧董，標(biāo)有Return
        UIReturnKeyGo           ;//標(biāo)有Go的藍(lán)色按鈕
        UIReturnKeyGoogle       ;//標(biāo)有Google的藍(lán)色按鈕，用語搜索
        UIReturnKeyJoin         ;//標(biāo)有Join的藍(lán)色按鈕
        UIReturnKeyNext         ;//標(biāo)有Next的藍(lán)色按鈕
        UIReturnKeyRoute        ;//標(biāo)有Route的藍(lán)色按鈕
        UIReturnKeySearch       ;//標(biāo)有Search的藍(lán)色按鈕
        UIReturnKeySend         ;//標(biāo)有Send的藍(lán)色按鈕
        UIReturnKeyYahoo        ;//標(biāo)有Yahoo的藍(lán)色按鈕
        UIReturnKeyYahoo        ;//標(biāo)有Yahoo的藍(lán)色按鈕
        UIReturnKeyEmergencyCall;//緊急呼叫按鈕
/**************************************************************************************/

leftView和leftViewMode:最右或者最左側(cè)(光標(biāo)前的占位符)

UIView *v = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 40, 2)];
v.backgroundColor = [UIColor redColor];
ettxf.leftView= v;
ettxf.leftViewMode = UITextFieldViewModeWhileEditing;

/**************************************************************************************/
        UITextFieldViewModeNever        ;//從不出現(xiàn)
        UITextFieldViewModeWhileEditing ;//當(dāng)編輯時出現(xiàn)
        UITextFieldViewModeUnlessEditing;//
        UITextFieldViewModeAlways       ;//一直存在
/**************************************************************************************/

keyboardAppearance:鍵盤外觀

ettxf.keyboardAppearance=UIKeyboardAppearanceDefault;

/****************************UIReturnKeyType*******************************************/
        UIKeyboardAppearanceDefault ;//默認(rèn)外觀破停，淺灰色
        UIKeyboardAppearanceAlert   ;//深灰石墨色
/**************************************************************************************/```

補充重點(addTaget:...)

[ettxf addTarget:self  action:@selector(<#方法名稱#>) forControlEvents:<#觸發(fā)狀態(tài)#>]

[ettxf addTarget:self
          action:@selector(textFieldDidChange:)//私有方法
forControlEvents:UIControlEventEditingChanged];

- (void)textFieldDidChange:(UITextField*)textField{//類似UIButton addTag..監(jiān)聽方法
    NSLog(@"輸入框內(nèi)容 = %@",textField.text);
}

/****************************UIControlEvents********************************/
        UIControlEventEditingDidBegin      ;//
        UIControlEventEditingChanged       ;//
        UIControlEventEditingDidEnd        ;//
        UIControlEventEditingDidEndOnExit  ;//
/**************************************************************************

//補充重點(NotificaitonCenter監(jiān)聽)

NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
        [center addObserver:self
                   selector:@selector(texfFieldNotification:)
                       name:UITextFieldTextDidChangeNotification object:nil];

- (void)texfFieldNotification:(NSNotification*)noti{//私有方法
    NSLog(@"輸入款變化了");
}

/***************************************************************************/
      UITextFieldTextDidBeginEditingNotification  ;//監(jiān)聽開始編輯
      UITextFieldTextDidChangeNotification        ;//監(jiān)聽正在編輯
      UITextFieldTextDidEndEditingNotification    ;//監(jiān)聽結(jié)束編輯
/***************************************************************************/

限制字符串輸出長度

[ettxf addTarget:self action:@selector(textFieldDidChange:) forControlEvents:UIControlEventEditingChanged];

//這樣就可以更好地限制輸入長度：
- (void)textFieldDidChange:(UITextField *)textField {
    if (textField == self.titleField) {
        if (textField.text.length > 12) {
            textField.text = [textField.text substringToIndex:12];
        }
    }
}

• 方法缺陷：對純字符的統(tǒng)計無影響翅楼，如果使用拼音輸入法時，方法的最后1個參數(shù)string接受的是輸入的字母真慢，而不是選擇的漢字毅臊，結(jié)果：當(dāng)想輸入文字“我愛你”，輸入拼音“woaini”黑界，每輸入一個字母便會進(jìn)入方法管嬉，統(tǒng)計的字符長度是字母的長度，實際上漢字還未超過限制長度朗鸠，但是字母的長度超過了導(dǎo)致無法繼續(xù)輸入

完美解決辦法：

- (void)textFieldDidChange:(UITextField *)textField {
    NSInteger kMaxLength = 12;
    NSString *toBeString = textField.text;
    NSString *lang = [[UIApplication sharedApplication] textInputMode].primaryLanguage; //ios7之前使用[UITextInputMode currentInputMode].primaryLanguage
    if ([lang isEqualToString:@"zh-Hans"]) { //中文輸入
        UITextRange *selectedRange = [textField markedTextRange];
        //獲取高亮部分
        UITextPosition *position = [textField positionFromPosition:selectedRange.start offset:0];
        if (!position) {// 沒有高亮選擇的字蚯撩，則對已輸入的文字進(jìn)行字?jǐn)?shù)統(tǒng)計和限制
            if (toBeString.length > kMaxLength) {
                textField.text = [toBeString substringToIndex:kMaxLength];
            }
        } else{//有高亮選擇的字符串，則暫不對文字進(jìn)行統(tǒng)計和限制

        }
    } else {//中文輸入法以外的直接對其統(tǒng)計限制即可烛占，不考慮其他語種情況
        if (toBeString.length > kMaxLength) {
            textField.text = [toBeString substringToIndex:kMaxLength];
        }
    }
}

自定義鍵盤屬性(inputView)

//自定義鍵盤胎挎，將原有的鍵盤隱藏，顯示當(dāng)前自定義視圖
UIView *keyBoardContent = [[UIView alloc]initWithFrame:CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, 100)];
keyBoardContent.backgroundColor = [UIColor darkGrayColor];

ettxf.inputView = keyBoardContent;

自定義輔助鍵盤視圖(inputAccessoryView)

UIView *subView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 80)];
subView.backgroundColor = [UIColor greenColor];
ettxf.inputAccessoryView = subView;

補充重點 （監(jiān)聽鍵盤出現(xiàn),知曉鍵盤CGRect）

- (void)efObserverKeyBoardShowAndHidde{
    //注冊鍵盤出現(xiàn)
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyBoardWasShow:)
                                                 name:UIKeyboardWillShowNotification
                                               object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyBoardWillBeHidden:)
                                                 name:UIKeyboardWillHideNotification
                                               object:nil];
}
- (void)keyBoardWasShow:(NSNotification*)aNotification{
    NSLog(@"鍵盤出現(xiàn)");
    //鍵盤高度
    //CGRect keyBoardFrame = [[[aNotification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
}
-(void)keyBoardWillBeHidden:(NSNotification*)aNotification{
    NSLog(@"鍵盤消失");
}

- (void)removeObserver{//移除所有通知
    [[NSNotificationCenter defaultCenter]removeObserver:self];
}

補充屬性(水印提示文字顏色)

attributedPlaceholder:水印提示文字顏色


NSMutableAttributedString *attrString = [[NSMutableAttributedString alloc]initWithString:@"水印提示文字"];
[attrString addAttribute:NSForegroundColorAttributeNam
                   value:[UIColor redColor]
                   range:NSMakeRange(0, 2)];
ettxf.attributedPlaceholder =  attrString;

3.代理協(xié)議及委托方法

用戶不段的輸入忆家，可以控制達(dá)到某些條件犹菇，禁止輸入(如，輸入手機號碼<=11位)*

//!!!!!!!!!!!!!!重點!!!!!!!!!!!!!!
//限定輸入條件
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    //得到輸入框的內(nèi)容
    NSString * textString = [textField.text stringByReplacingCharactersInRange:range withString:string];

    if ([string isEqualToString:@"\n"]) {
        NSLog(@"回車");
    }
    if ([string isEqualToString:@""]) {
        NSLog(@"后退");
    }
    if ([string isEqualToString:@" "]) {
        NSLog(@"空格");
        //return NO;//禁止空格輸入
    }
    if (textString.length>4) {
        NSLog(@"輸入超過5位數(shù)");
    }

    //新思路-- xxx xxxx xxxx格式輸出手機號碼
      NSString * textString = [textField.text stringByReplacingCharactersInRange:range withString:string];
      if (textField == _phoneNumTFView.tf) {
          // 四位加一個空格
        if ([string isEqualToString:@""]) { // 刪除字符
                if (textString.length==4||textString.length==8) {
                    textField.text = [textField.text substringToIndex:textField.text.length - 1];
            }
        } else {
            //手機號輸入xxx xxxx xxxx
              if (textString.length==4||textString.length==9) {
                  textField.text = [NSString stringWithFormat:@"%@ ", textField.text];
              }
        }
        return textString.length<=13;
    } 
    return YES;
}

4.鍵盤收起方式

方式 1:
[_evtxf  resignFirstResponder];
方式 2:
[[[UIApplication sharedApplication]keyWindow] endEditing:YES];
方式 3:
[[UIApplication sharedApplication]sendAction:@selector(resignFirstResponder) to:nil from:nil forEvent:nil];
方式 4:
[self.view endEditing:YES];

5.Block代替代理協(xié)議

1.使用方法

        //使用前提條件：導(dǎo)入UITextField+Blocks.h文件
        UITextField *ettxf = [[UITextField alloc]init];
        .
        .
        .
        ettxf.delegate = self;//設(shè)置代理

        //推薦使用方法：
        [ettxf setShouldBegindEditingBlock:^BOOL(UITextField *textField) {
            return YES;
        }];
        [ettxf setShouldChangeCharactersInRangeBlock:^BOOL(UITextField *textField, NSRange range, NSString *string) {
            NSString *str = [textField.text stringByReplacingCharactersInRange:range withString:string];
            NSLog(@"%@ || %@",string,str);
            return YES;
        }];
        [ettxf setShouldEndEditingBlock:^BOOL(UITextField *textField) {
            return YES;
        }];

        //與推薦方式一致：（不太理解block的弦赖，建議直接使用以上方法）
        ettxf.shouldBegindEditingBlock = ^BOOL(UITextField *textField){
            return YES;
        };
        
        ettxf.shouldEndEditingBlock = ^BOOL(UITextField *textField){
            return YES;
        };
        
        ettxf.shouldChangeCharactersInRangeBlock = ^BOOL(UITextField *textField, NSRange range, NSString *string){
            NSString *str = [textField.text stringByReplacingCharactersInRange:range withString:string];
            NSLog(@"%@ || %@",string,str);
            return YES;
        };
        [self.view addSubview:ettxf];

UITextField+Blocks.h文件

#import <UIKit/UIKit.h>

@interface UITextField (Blocks)

/**
 *  即將開始編輯
 */
@property (copy, nonatomic) BOOL (^shouldBegindEditingBlock)(UITextField *textField);
/**
 *  即將結(jié)束編輯
 */
@property (copy, nonatomic) BOOL (^shouldEndEditingBlock)(UITextField *textField);
/**
 *  已經(jīng)開始編輯
 */
@property (copy, nonatomic) void (^didBeginEditingBlock)(UITextField *textField);
/**
 *  已經(jīng)結(jié)束編輯
 */
@property (copy, nonatomic) void (^didEndEditingBlock)(UITextField *textField);
/**
 *  正在編輯中
 */
@property (copy, nonatomic) BOOL (^shouldChangeCharactersInRangeBlock)(UITextField *textField, NSRange range, NSString *replacementString);
/**
 *  即將點擊return
 */
@property (copy, nonatomic) BOOL (^shouldReturnBlock)(UITextField *textField);
/**
 *  即將點擊clearButton
 */
@property (copy, nonatomic) BOOL (^shouldClearBlock)(UITextField *textField);

- (void)setShouldBegindEditingBlock:(BOOL (^)(UITextField *textField))shouldBegindEditingBlock;
- (void)setShouldEndEditingBlock:(BOOL (^)(UITextField *textField))shouldEndEditingBlock;
- (void)setDidBeginEditingBlock:(void (^)(UITextField *textField))didBeginEditingBlock;
- (void)setDidEndEditingBlock:(void (^)(UITextField *textField))didEndEditingBlock;
- (void)setShouldChangeCharactersInRangeBlock:(BOOL (^)(UITextField *textField, NSRange range, NSString *string))shouldChangeCharactersInRangeBlock;
- (void)setShouldClearBlock:(BOOL (^)(UITextField *textField))shouldClearBlock;
- (void)setShouldReturnBlock:(BOOL (^)(UITextField *textField))shouldReturnBlock;

@end

UITextField+Blocks.m文件

#import "UITextField+Blocks.h"
#import <objc/runtime.h>

typedef BOOL (^UITextFieldReturnBlock) (UITextField *textField);
typedef void (^UITextFieldVoidBlock) (UITextField *textField);
typedef BOOL (^UITextFieldCharacterChangeBlock) (UITextField *textField, NSRange range, NSString *replacementString);

@implementation UITextField (Blocks)

static const void *UITextFieldDelegateKey = &UITextFieldDelegateKey;
static const void *UITextFieldShouldBeginEditingKey = &UITextFieldShouldBeginEditingKey;
static const void *UITextFieldShouldEndEditingKey = &UITextFieldShouldEndEditingKey;
static const void *UITextFieldDidBeginEditingKey = &UITextFieldDidBeginEditingKey;
static const void *UITextFieldDidEndEditingKey = &UITextFieldDidEndEditingKey;
static const void *UITextFieldShouldChangeCharactersInRangeKey = &UITextFieldShouldChangeCharactersInRangeKey;
static const void *UITextFieldShouldClearKey = &UITextFieldShouldClearKey;
static const void *UITextFieldShouldReturnKey = &UITextFieldShouldReturnKey;

#pragma mark UITextField Delegate methods
+ (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
    UITextFieldReturnBlock block = textField.shouldBegindEditingBlock;
    if (block) {
        return block(textField);
    }
    id delegate = objc_getAssociatedObject(self, UITextFieldDelegateKey);
    if ([delegate respondsToSelector:@selector(textFieldShouldBeginEditing:)]) {
        return [delegate textFieldShouldBeginEditing:textField];
    }
    // return default value just in case
    return YES;
}
+ (BOOL)textFieldShouldEndEditing:(UITextField *)textField
{
    UITextFieldReturnBlock block = textField.shouldEndEditingBlock;
    if (block) {
        return block(textField);
    }
    id delegate = objc_getAssociatedObject(self, UITextFieldDelegateKey);
    if ([delegate respondsToSelector:@selector(textFieldShouldEndEditing:)]) {
        return [delegate textFieldShouldEndEditing:textField];
    }
    // return default value just in case
    return YES;
}
+ (void)textFieldDidBeginEditing:(UITextField *)textField
{
    UITextFieldVoidBlock block = textField.didBeginEditingBlock;
    if (block) {
        block(textField);
    }
    id delegate = objc_getAssociatedObject(self, UITextFieldDelegateKey);
    if ([delegate respondsToSelector:@selector(textFieldDidBeginEditing:)]) {
        [delegate textFieldDidBeginEditing:textField];
    }
}
+ (void)textFieldDidEndEditing:(UITextField *)textField
{
    UITextFieldVoidBlock block = textField.didEndEditingBlock;
    if (block) {
        block(textField);
    }
    id delegate = objc_getAssociatedObject(self, UITextFieldDelegateKey);
    if ([delegate respondsToSelector:@selector(textFieldDidEndEditing:)]) {
        [delegate textFieldDidBeginEditing:textField];
    }
}
+ (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    UITextFieldCharacterChangeBlock block = textField.shouldChangeCharactersInRangeBlock;
    if (block) {
        return block(textField,range,string);
    }
    id delegate = objc_getAssociatedObject(self, UITextFieldDelegateKey);
    if ([delegate respondsToSelector:@selector(textField:shouldChangeCharactersInRange:replacementString:)]) {
        return [delegate textField:textField shouldChangeCharactersInRange:range replacementString:string];
    }
    return YES;
}
+ (BOOL)textFieldShouldClear:(UITextField *)textField
{
    UITextFieldReturnBlock block = textField.shouldClearBlock;
    if (block) {
        return block(textField);
    }
    id delegate = objc_getAssociatedObject(self, UITextFieldDelegateKey);
    if ([delegate respondsToSelector:@selector(textFieldShouldClear:)]) {
        return [delegate textFieldShouldClear:textField];
    }
    return YES;
}
+ (BOOL)textFieldShouldReturn:(UITextField *)textField
{
    UITextFieldReturnBlock block = textField.shouldReturnBlock;
    if (block) {
        return block(textField);
    }
    id delegate = objc_getAssociatedObject(self, UITextFieldDelegateKey);
    if ([delegate respondsToSelector:@selector(textFieldShouldReturn:)]) {
        return [delegate textFieldShouldReturn:textField];
    }
    return YES;
}
#pragma mark Block setting/getting methods
- (BOOL (^)(UITextField *))shouldBegindEditingBlock
{
    return objc_getAssociatedObject(self, UITextFieldShouldBeginEditingKey);
}
- (void)setShouldBegindEditingBlock:(BOOL (^)(UITextField *))shouldBegindEditingBlock
{
    [self setDelegateIfNoDelegateSet];
    objc_setAssociatedObject(self, UITextFieldShouldBeginEditingKey, shouldBegindEditingBlock, OBJC_ASSOCIATION_COPY);
}
- (BOOL (^)(UITextField *))shouldEndEditingBlock
{
    return objc_getAssociatedObject(self, UITextFieldShouldEndEditingKey);
}
- (void)setShouldEndEditingBlock:(BOOL (^)(UITextField *))shouldEndEditingBlock
{
    [self setDelegateIfNoDelegateSet];
    objc_setAssociatedObject(self, UITextFieldShouldEndEditingKey, shouldEndEditingBlock, OBJC_ASSOCIATION_COPY);
}
- (void (^)(UITextField *))didBeginEditingBlock
{
    return objc_getAssociatedObject(self, UITextFieldDidBeginEditingKey);
}
- (void)setDidBeginEditingBlock:(void (^)(UITextField *))didBeginEditingBlock
{
    [self setDelegateIfNoDelegateSet];
    objc_setAssociatedObject(self, UITextFieldDidBeginEditingKey, didBeginEditingBlock, OBJC_ASSOCIATION_COPY);
}
- (void (^)(UITextField *))didEndEditingBlock
{
    return objc_getAssociatedObject(self, UITextFieldDidEndEditingKey);
}
- (void)setDidEndEditingBlock:(void (^)(UITextField *))didEndEditingBlock
{
    [self setDelegateIfNoDelegateSet];
    objc_setAssociatedObject(self, UITextFieldDidEndEditingKey, didEndEditingBlock, OBJC_ASSOCIATION_COPY);
}
- (BOOL (^)(UITextField *, NSRange, NSString *))shouldChangeCharactersInRangeBlock
{
    return objc_getAssociatedObject(self, UITextFieldShouldChangeCharactersInRangeKey);
}
- (void)setShouldChangeCharactersInRangeBlock:(BOOL (^)(UITextField *, NSRange, NSString *))shouldChangeCharactersInRangeBlock
{
    [self setDelegateIfNoDelegateSet];
    objc_setAssociatedObject(self, UITextFieldShouldChangeCharactersInRangeKey, shouldChangeCharactersInRangeBlock, OBJC_ASSOCIATION_COPY);
}
- (BOOL (^)(UITextField *))shouldReturnBlock
{
    return objc_getAssociatedObject(self, UITextFieldShouldReturnKey);
}
- (void)setShouldReturnBlock:(BOOL (^)(UITextField *))shouldReturnBlock
{
    [self setDelegateIfNoDelegateSet];
    objc_setAssociatedObject(self, UITextFieldShouldReturnKey, shouldReturnBlock, OBJC_ASSOCIATION_COPY);
}
- (BOOL (^)(UITextField *))shouldClearBlock
{
    return objc_getAssociatedObject(self, UITextFieldShouldClearKey);
}
- (void)setShouldClearBlock:(BOOL (^)(UITextField *textField))shouldClearBlock
{
    [self setDelegateIfNoDelegateSet];
    objc_setAssociatedObject(self, UITextFieldShouldClearKey, shouldClearBlock, OBJC_ASSOCIATION_COPY);
}
#pragma mark control method
/*
 Setting itself as delegate if no other delegate has been set. This ensures the UITextField will use blocks if no delegate is set.
 */
- (void)setDelegateIfNoDelegateSet
{
    if (self.delegate != (id<UITextFieldDelegate>)[self class]) {
        objc_setAssociatedObject(self, UITextFieldDelegateKey, self.delegate, OBJC_ASSOCIATION_ASSIGN);
        self.delegate = (id<UITextFieldDelegate>)[self class];
    }
}
@end