修改光標顏色、placeholder 顏色，手機號輸入格式化

• 修改光標顏色

  //修改textField光標顏色碱妆，
  [textField setTintColor:[UIColor redColor]];
  //設置UITextField的光標顏色
  // [[UITextField appearance] setTintColor:[UIColor redColor];
  

• 修改placeholder 顏色

通過設置UITextField的attributedPlaceholder屬性唇牧，修改它的顏色 。因為經常用到咨跌，創(chuàng)建UITextField 的分類，將其封裝硼婿。

/** 設置textfield的placeholder及其顏色  */
-(void)dh_setPlaceholder:(NSString *)placeholder andPlaceholderColor:(UIColor *)placeholderColor {
    NSDictionary *attributes = @{
                                 NSForegroundColorAttributeName:placeholderColor,
                                 NSFontAttributeName:self.font
                                 };
    NSAttributedString *attrString = [[NSAttributedString alloc] initWithString:placeholder attributes:attributes];
    self.attributedPlaceholder = attrString;
}

• 手機號輸入格式化

  在用戶輸入電話號碼時锌半，自動將其格式化為123 4567 8910。

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

  把textField中位置為range的字符串替換為string字符串寇漫；此函數在textField內容被修改時調用刊殉；使用這個方法來驗證使用時用戶輸入的類型。

  @param textField textField

  @param range UITextField控件中光標選中的字符串州胳，即被替換的字符串冗澈；range.length為0時，表示在位置range.location插入string陋葡。

  @param string 替換字符串亚亲；string.length為0時，表示刪除腐缤。

  @return YES捌归，表示修改生效；NO岭粤，表示不做修改惜索，textField的內容不變。

  實現(xiàn)代碼(ps:一下代碼均實現(xiàn)在UITextField的分類中)：

  -(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
      //在輸入或刪除前的光標位置
      NSRange currentRange = [self cursorPosition];
      //輸入或刪除前的內容
      NSString *previousContent = textField.text;
      // 限制只能輸入數字
      NSCharacterSet *characterSet = [NSCharacterSet characterSetWithCharactersInString:@"0123456789\b"];
      string = [string stringByReplacingOccurrencesOfString:@" " withString:@""];
      if ([string rangeOfCharacterFromSet:[characterSet invertedSet]].location != NSNotFound) {
          return NO;
      }
      //把textField中位置為range的字符串替換為string字符串
      NSString *handleText = [previousContent stringByReplacingCharactersInRange:range withString:string];
      //純數字的字符串
      NSString *onlyDigitStr = [handleText stringByReplacingOccurrencesOfString:@" " withString:@""];
      NSMutableString *temMstr = [NSMutableString new];
      for (NSInteger i = 0; i < onlyDigitStr.length; i++) {
          if (i == 3 || i == 7) {
              [temMstr appendString:@" "];
          }
          unichar digitchar = [onlyDigitStr characterAtIndex:i];
          [temMstr appendString:[NSString stringWithCharacters:&digitchar length:1]];
      }
      if (temMstr.length >= 14) {
          return NO;
      }
      [textField setText:temMstr];
  /*
      //不做任何處理時剃浇，顯示的內容
      NSString *text = [previousContent stringByReplacingCharactersInRange:range withString:string];
      text = [text stringByReplacingOccurrencesOfString:@" " withString:@""];
      NSMutableString *temString = [NSMutableString stringWithString:text];
      [temString insertString:@" " atIndex:0];
      text = temString;
      NSString *newString = @"";
      while (text.length > 0) {
          NSString *subString = [text substringToIndex:MIN(text.length, 4)];
          newString = [newString stringByAppendingString:subString];
          if (subString.length == 4) {
              newString = [newString stringByAppendingString:@" "];
          }
          text = [text substringFromIndex:MIN(text.length, 4)];
      }
      newString = [newString stringByTrimmingCharactersInSet:[characterSet invertedSet]];
      if (newString.length >= 14) {
          return NO;
      }
      [textField setText:newString];
  */
      if (string.length == 0) {
          //刪除
          currentRange.location --;
          if (currentRange.location == 4 || currentRange.location == 9) {
              currentRange.location --;
          }
      }
      else {
          currentRange.location += string.length;
          if (currentRange.location == 4 || currentRange.location == 9) {
              currentRange.location ++;
          }
      }
      [self setCursorPosition:currentRange];
      return NO;
  }
  /**  光標位置  */
  - (NSRange)cursorPosition {
      UITextPosition* beginning = self.beginningOfDocument;
      UITextRange* selectedRange = self.selectedTextRange;
      UITextPosition* selectionStart = selectedRange.start;
      UITextPosition* selectionEnd = selectedRange.end;
      const NSInteger location = [self offsetFromPosition:beginning toPosition:selectionStart];
      const NSInteger length = [self offsetFromPosition:selectionStart toPosition:selectionEnd];
      return NSMakeRange(location, length);
  }
  /**  設置光標位置  */
  - (void)setCursorPosition:(NSRange) range {
      UITextPosition* beginning = self.beginningOfDocument;
      UITextPosition* startPosition = [self positionFromPosition:beginning offset:range.location];
      UITextPosition* endPosition = [self positionFromPosition:beginning offset:range.location + range.length];
      UITextRange* cursorPosition = [self textRangeFromPosition:startPosition toPosition:endPosition];
      [self setSelectedTextRange:cursorPosition];
  }