按钮样式可自定义，下载demo在PZXInputView可实现样式自定义

github地址：https://github.com/PZXforXcode/PZXSecurityKeyBoard

效果：

keyboard.gif

用法：

#import "PZXInputView.h"
@property (strong, nonatomic)  PZXInputView *inputView;

    _inputView = [[PZXInputView alloc]initWithFrame:CGRectMake(0, 0, 200, 260)];
    _inputView.backgroundColor = [UIColor whiteColor];
    _inputView.layer.borderWidth = 1;
    _inputView.layer.borderColor = [UIColor lightGrayColor].CGColor;
    _inputView.tf = self.tf;

    self.tf.inputView = _inputView;

车牌号

 //车牌号键盘用法
    _carInput = [[LicensePlateInputView alloc]init];
    __weak typeof(self)weakSelf = self;
    _carInput.sendTextBlock = ^(NSString * _Nonnull plateString) {
        weakSelf.CarTF.text = plateString;
    };
   [self.CarTF addTarget:self action:@selector(textChanged:) forControlEvents:UIControlEventEditingChanged];
    self.CarTF.inputView = self.carInput;

//用这个方法把变换的值传回给input 为了切换键盘样式
-(void)textChanged:(UITextField *)textField{
    NSLog(@"%@",textField.text);
    //这里样将键盘值传回plateStr，让键盘切换
    self.carInput.plateStr = textField.text;
}

github地址：https://github.com/PZXforXcode/PZXSecurityKeyBoard