Simulator Screen Shot - iPhone 8 - 2018-04-26 at 14.00.04.png

公司项目做一个效果类似于微信支付宝的密码框，这里对效果做了一个封装：
由于要求输入框不能有拷贝粘贴的效果，这里就写了一个继承UITextField的一个子类：NOCopyTextField，并重写- (BOOL)canPerformAction:(SEL)action withSender:(nullable id)sender；

• (BOOL)canPerformAction:(SEL)action withSender:(id)sender
  {
  [super canPerformAction:action withSender:sender];
  if (action == @selector(paste:))//禁止粘贴
  return NO;
  if (action == @selector(select:))// 禁止选择
  return NO;
  if (action == @selector(selectAll:))// 禁止全选
  return NO;
  return NO;
  }
  我的思路是：自定义一个View视图，首先将要显示给用户信息的按钮（我这里用的按钮，因为有背景图片和文字）添加到这个View视图上，并将一个UITextField也添加到这个View视图上面，注意要覆盖在这些按钮上面，并设置这个UITextField的光标颜色和字体颜色等设置为透明色，当点击UITextField的时候监听输入事件，并截取字符分别添加到上面的按钮上面。大致的思路是这样的，具体代码如下：
  在.h文件中

import "WXPasswordView.h"

@property (nonatomic,strong) NOCopyTextField *textfield;
@property (nonatomic,strong) NSMutableArray *btnsArr;

• (instancetype)initWithFrame:(CGRect)frame withCountNum:(int)count;
  .m文件中

import "WXPasswordView.h"

define Selfsize self.bounds.size

@interface WXPasswordView()<UITextFieldDelegate>
{
int _count;
}
@end
@implementation WXPasswordView

• (NSMutableArray *)btnsArr{
  if (!_btnsArr) {
  _btnsArr = [[NSMutableArray alloc]init];
  }
  return _btnsArr;
  }

• (instancetype)initWithFrame:(CGRect)frame withCountNum:(int)count{
  self = [super initWithFrame:frame];
  _count = count;
  if (self) {
  [self createUI];
  }
  return self;
  }

• (void)createUI{

  float btnWidth = (Selfsize.width - 75)/_count;
  float btnHeigth = btnWidth;
  for (int i = 0; i < _count; i++) {
  UIButton btn = [UIButton buttonWithType:UIButtonTypeCustom];
  [btn setBackgroundImage:[UIImage imageNamed:@"square"] forState:UIControlStateNormal];
  btn.titleLabel.font = [UIFont systemFontOfSize:30];
  btn.frame = CGRectMake(i(btnWidth + 25) , (Selfsize.height - btnHeigth)/2.0, btnWidth, btnHeigth);
  [self addSubview:btn];
  [self.btnsArr addObject:btn];
  }
  _textfield = [[NOCopyTextField alloc]initWithFrame:CGRectMake(0, 0, Selfsize.width - 20, 100)];
  _textfield.delegate = self;
  _textfield.backgroundColor = [UIColor clearColor];
  _textfield.textColor = [UIColor clearColor];
  _textfield.keyboardType = UIKeyboardTypeNumberPad;

  //输入框光标的颜色为白色
  _textfield.tintColor = [UIColor clearColor];
  [_textfield addTarget:self action:@selector(textFieldDidChange:) forControlEvents:UIControlEventEditingChanged];
  [self addSubview:_textfield];

}

• (BOOL)textField:(UITextField )textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString )string{
  if([string isEqualToString:@"\n"]) {
  //按回车关闭键盘
  [textField resignFirstResponder];
  return NO;
  } else if(string.length == 0) {
  //判断是不是删除键
  return YES;
  }
  else if(textField.text.length >= _count) {
  //输入的字符个数大于4，则无法继续输入，返回NO表示禁止输入
  NSLog(@"输入的字符个数大于4，忽略输入");
  [textField resignFirstResponder];
  return NO;
  } else {
  return YES;
  }
  }
  /

• 重置显示的点
  */

• (void)textFieldDidChange:(UITextField *)textField
  {
  NSLog(@"%@", textField.text);
  for (int i = 0; i < _count; i++) {
  UIButton *btn = (UIButton *)[self.btnsArr objectAtIndex:i];
  if (i<textField.text.length) {
  [btn setTitle:[NSString stringWithFormat:@"%c",[textField.text characterAtIndex:i]] forState:UIControlStateNormal];
  }else{
  [btn setTitle:@"" forState:UIControlStateNormal];
  }
  }
  if (textField.text.length == _count) {
  [textField resignFirstResponder];

  }
  }
  这样在一个Controller里面直接调用这个封装好的View就可以了
  @property (nonatomic,strong) WXPasswordView *passView;//弄一个全局变量，方便使用
  _passView = [[WXPasswordView alloc]initWithFrame:CGRectMake(10, 100, screen_size.width - 20, 100) withCountNum:4];
  [self.view addSubview:self.passView];
  代码就到这里吧！后面要用到文本框的字符串的时候使用self.passView.textfield.text就可以获取到