@interface IDVertificationCodeInputView : UIView
/**背景圖片*/
@property (nonatomic, copy) NSString *backgroudImageName;
/**驗(yàn)證碼/密碼的位數(shù)*/
@property (nonatomic, assign) NSInteger numberOfVertificationCode;
/**控制驗(yàn)證碼/密碼是否密文顯示*/
@property (nonatomic, assign) bool secureTextEntry;
/**驗(yàn)證碼/密碼內(nèi)容，可以通過(guò)該屬性拿到驗(yàn)證碼/密碼輸入框中驗(yàn)證碼/密碼的內(nèi)容*/
@property (nonatomic, copy) NSString *vertificationCode;
@end

@interface IDVertificationCodeInputView () <UITextFieldDelegate>
/**用于獲取鍵盤(pán)輸入的內(nèi)容，實(shí)際不顯示*/
@property (nonatomic, strong) UITextField *textField;
/**驗(yàn)證碼/密碼輸入框的背景圖片*/
@property (nonatomic, strong) UIImageView *backgroundImageView;
/**實(shí)際用于顯示驗(yàn)證碼/密碼的label*/
@property (nonatomic, strong) IDLabel *label;
@end

@interface IDLabel : UILabel
/**驗(yàn)證碼/密碼的位數(shù)*/
@property (nonatomic, assign) NSInteger numberOfVertificationCode;
/**控制驗(yàn)證碼/密碼是否密文顯示*/
@property (nonatomic, assign) bool secureTextEntry;
@end

- (instancetype)initWithFrame:(CGRect)frame {
  if (self = [super initWithFrame:frame]) {
    // 設(shè)置透明背景色，保證vertificationCodeInputView顯示的frame為backgroundImageView的frame
    self.backgroundColor = [UIColor clearColor];
    // 設(shè)置驗(yàn)證碼/密碼的位數(shù)默認(rèn)為四位
    self.numberOfVertificationCode = 4;
    /* 調(diào)出鍵盤(pán)的textField */
    self.textField = [[UITextField alloc] initWithFrame:self.bounds];
    // 隱藏textField，通過(guò)點(diǎn)擊IDVertificationCodeInputView使其成為第一響應(yīng)者，來(lái)彈出鍵盤(pán)
    self.textField.hidden = YES;
    self.textField.keyboardType = UIKeyboardTypeNumberPad;
    self.textField.delegate = self;
    // 將textField放到最后邊
    [self insertSubview:self.textField atIndex:0];
    /* 添加用于顯示驗(yàn)證碼/密碼的label */
    self.label = [[IDLabel alloc] initWithFrame:self.bounds];
    self.label.numberOfVertificationCode = self.numberOfVertificationCode;
    self.label.secureTextEntry = self.secureTextEntry;
    self.label.font = self.textField.font;
    [self addSubview:self.label];
  }
  return self;
}

- (void)setBackgroudImageName:(NSString *)backgroudImageName {
  _backgroudImageName = backgroudImageName;
  // 若用戶設(shè)置了背景圖片，則添加背景圖片
  self.backgroundImageView = [[UIImageView alloc] initWithFrame:self.bounds];
  self.backgroundImageView.image = [UIImage imageNamed:self.backgroudImageName];
  // 將背景圖片插入到label的后邊，避免遮擋驗(yàn)證碼/密碼的顯示
  [self insertSubview:self.backgroundImageView belowSubview:self.label];
}

- (void)setNumberOfVertificationCode:(NSInteger)numberOfVertificationCode {
  _numberOfVertificationCode = numberOfVertificationCode;
  // 保持label的驗(yàn)證碼/密碼位數(shù)與IDVertificationCodeInputView一致，此時(shí)label一定已經(jīng)被創(chuàng)建
  self.label.numberOfVertificationCode = _numberOfVertificationCode;
}
- (void)setSecureTextEntry:(bool)secureTextEntry {
  _secureTextEntry = secureTextEntry;
  self.label.secureTextEntry = _secureTextEntry;
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
  [self.textField becomeFirstResponder];
}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
  // 判斷是不是“刪除”字符
  if (string.length != 0) {// 不是“刪除”字符
    // 判斷驗(yàn)證碼/密碼的位數(shù)是否達(dá)到預(yù)定的位數(shù)
    if (textField.text.length < self.numberOfVertificationCode) {
      self.label.text = [textField.text stringByAppendingString:string];
      self.vertificationCode = self.label.text;
      return YES;
    } else {
      return NO;
    }
  } else { // 是“刪除”字符
    self.label.text = [textField.text substringToIndex:textField.text.length - 1];
    self.vertificationCode = self.label.text;
    return YES;
  }
}

//重寫(xiě)setText方法，當(dāng)text改變時(shí)手動(dòng)調(diào)用drawRect方法，將text的內(nèi)容按指定的格式繪制到label上
- (void)setText:(NSString *)text {
  [super setText:text];
  // 手動(dòng)調(diào)用drawRect方法
  [self setNeedsDisplay];
}

// 按照指定的格式繪制驗(yàn)證碼/密碼
- (void)drawRect:(CGRect)rect {
  //計(jì)算每位驗(yàn)證碼/密碼的所在區(qū)域的寬和高
  float width = rect.size.width / (float)self.numberOfVertificationCode;;
  float height = rect.size.height;
  // 將每位驗(yàn)證碼/密碼繪制到指定區(qū)域
  for (int i = 0; i < self.text.length; i++) {
    // 計(jì)算每位驗(yàn)證碼/密碼的繪制區(qū)域
    CGRect tempRect = CGRectMake(i * width, 0, width, height);
    if (self.secureTextEntry) { // 密碼，顯示圓點(diǎn)
      UIImage *dotImage = [UIImage imageNamed:@"dot"];
      // 計(jì)算圓點(diǎn)的繪制區(qū)域
      CGPoint securityDotDrawStartPoint = CGPointMake(width * i + (width - dotImage.size.width) / 2.0, (tempRect.size.height - dotImage.size.height) / 2.0);
      // 繪制圓點(diǎn)
      [dotImage drawAtPoint:securityDotDrawStartPoint];
    } else { // 驗(yàn)證碼，顯示數(shù)字
      // 遍歷驗(yàn)證碼/密碼的每個(gè)字符
      NSString *charecterString = [NSString stringWithFormat:@"%c", [self.text characterAtIndex:i]];
      // 設(shè)置驗(yàn)證碼/密碼的現(xiàn)實(shí)屬性
      NSMutableDictionary *attributes = [[NSMutableDictionary alloc] init];
      attributes[NSFontAttributeName] = self.font;
      // 計(jì)算每位驗(yàn)證碼/密碼的繪制起點(diǎn)（為了使驗(yàn)證碼/密碼位于tempRect的中部，不應(yīng)該從tempRect的重點(diǎn)開(kāi)始繪制）
      // 計(jì)算每位驗(yàn)證碼/密碼的在指定樣式下的size
      CGSize characterSize = [charecterString sizeWithAttributes:attributes];
      CGPoint vertificationCodeDrawStartPoint = CGPointMake(width * i + (width - characterSize.width) / 2.0, (tempRect.size.height - characterSize.height) / 2.0);
      // 繪制驗(yàn)證碼/密碼
      [charecterString drawAtPoint:vertificationCodeDrawStartPoint withAttributes:attributes];
    }
  }
}

- (void)viewDidLoad {
  [super viewDidLoad];
  self.view.backgroundColor = [UIColor lightGrayColor];
  self.vertificationCodeInputView = [[IDVertificationCodeInputView alloc] initWithFrame:CGRectMake(50, 250, 200, 45)];
  self.vertificationCodeInputView.backgroudImageName = @"1";
  // 驗(yàn)證碼（顯示數(shù)字）
  self.vertificationCodeInputView.secureTextEntry = NO;
  //self.vertificationCodeInputView.secureTextEntry = YES;
  [self.view addSubview:self.vertificationCodeInputView];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
  NSLog(@"%@", self.vertificationCodeInputView.vertificationCode);
}