iOS dynamic verification code implementation code

//
// 
// BSbracelet
//
// Created by Christopher on 17/5/16.
// Copyright © 2017 ZTracy. All rights reserved.//
#import <UIKit/>
@interface AuthcodeView : UIView
@property (strong, nonatomic) NSArray *dataArray;//Array of character material@property (strong, nonatomic) NSMutableString *authCodeStr;//Verification code string@end
//
// 
// BSbracelet
//
// Created by Christopher on 17/5/16.
// Copyright © 2017 ZTracy. All rights reserved.//
#import ""
#define kRandomColor [UIColor colorWithRed:arc4random() % 256 / 256.0 green:arc4random() % 256 / 256.0 blue:arc4random() % 256 / 256.0 alpha:1.0];
#define kLineCount 6
#define kLineWidth 1.0
#define kCharCount 4
#define kFontSize [UIFont systemFontOfSize:arc4random() % 5 + 15]
@implementation AuthcodeView
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
  // Drawing code
}
*/
- (instancetype)initWithFrame:(CGRect)frame
{
  self = [super initWithFrame:frame];
  if (self)
  {
     = 5.0f;
     = YES;
     = kRandomColor;
    [self getAuthcode];//Get random verification code  }
  return self;
}
#pragma mark Get random verification code- (void)getAuthcode
{
  //Stand material  _dataArray = [[NSArray alloc] initWithObjects:@"0",@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"A",@"B",@"C",@"D",@"E",@"F",@"G",@"H",@"I",@"J",@"K",@"L",@"M",@"N",@"O",@"P",@"Q",@"R",@"S",@"T",@"U",@"V",@"W",@"X",@"Y",@"Z",@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",@"i",@"j",@"k",@"l",@"m",@"n",@"o",@"p",@"q",@"r",@"s",@"t",@"u",@"v",@"w",@"x",@"y",@"z",nil];
  _authCodeStr = [[NSMutableString alloc] initWithCapacity:kCharCount];
  // Randomly select the string of the required number from the array and splice it into a verification code string  for (int i = 0; i < kCharCount; i++)
  {
    NSInteger index = arc4random() % (_dataArray.count-1);
    NSString *tempStr = [_dataArray objectAtIndex:index];
    _authCodeStr = (NSMutableString *)[_authCodeStr stringByAppendingString:tempStr];
  }
}
#pragma mark Click the interface to switch verification code- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
  [self getAuthcode];
  //setNeedsDisplay calls the drawRect method to implement view drawing  [self setNeedsDisplay];
}
- (void)drawRect:(CGRect)rect
{
  [super drawRect:rect];
  //Set random background colors   = kRandomColor;
  // Calculate the position of each string according to the verification code string to be displayed, and calculate the position of each string according to the length.  NSString *text = [NSString stringWithFormat:@"%@",_authCodeStr];
  CGSize cSize = [@"A" sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:20]}];
  int width = / - ;
  int height =  - ;
  CGPoint point;
  //Draw each character in sequence, and you can set the font size, color, style, etc. of each character displayed.  float pX,pY;
  for ( int i = 0; i<; i++)
  {
    pX = arc4random() % width + / * i;
    pY = arc4random() % height;
    point = CGPointMake(pX, pY);
    unichar c = [text characterAtIndex:i];
    NSString *textC = [NSString stringWithFormat:@"%C", c];
    [textC drawAtPoint:point withAttributes:@{NSFontAttributeName:kFontSize}];
  }
  //Call drawRect: Before, the system will press a CGContextRef into the stack, and calling UIGraphicsGetCurrentContext() will take the CGContextRef at the top of the stack.  CGContextRef context = UIGraphicsGetCurrentContext();
  //Set line width  CGContextSetLineWidth(context, kLineWidth);
  //Draw the interference line  for (int i = 0; i < kLineCount; i++)
  {
    UIColor *color = kRandomColor;
    CGContextSetStrokeColorWithColor(context, );//Set line fill color    //Set the starting point of the line    pX = arc4random() % (int);
    pY = arc4random() % (int);
    CGContextMoveToPoint(context, pX, pY);
    //Set the line end point    pX = arc4random() % (int);
    pY = arc4random() % (int);
    CGContextAddLineToPoint(context, pX, pY);
    //Draw lines    CGContextStrokePath(context);
  }
}
@end
use
-(void)recordBtnClick:(UIButton *)recordBtn
{
  DomodelView = [[UIView alloc]initWithFrame:CGRectMake(0,0,kScreenWidth,kScreenHeight)];
   = [UIColor colorWithRed:0.3 green:0.3 blue:0.3 alpha:0.6];
  authBgview = [[UIView alloc]initWithFrame:CGRectMake(30, 120, -60, 220)];
   = [UIColor whiteColor]; //Show the verification code interface   = 8;
   = YES;
  authCodeView = [[AuthcodeView alloc] initWithFrame:CGRectMake(10, 10, kScreenWidth-80, 45)];
  [authBgview addSubview:authCodeView];
    // Prompt text  UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(10, 65, kScreenWidth-80, 40)];
   = @"Click on the image to change the verification code";
   = [UIFont systemFontOfSize:15];
   = [UIColor grayColor];
  [authBgview addSubview:label];
  //Add input box  _input = [[UITextField alloc] initWithFrame:CGRectMake(10, 120, kScreenWidth-80, 40)];
  _input. = [UIColor lightGrayColor].CGColor;
  _input. = 2.0;
  _input. = 5.0;
  _input.font = [UIFont systemFontOfSize:21];
  _input.placeholder = @"Please enter the verification code!";
  _input.clearButtonMode = UITextFieldViewModeWhileEditing;
  _input.backgroundColor = [UIColor clearColor];
  _input.textAlignment = NSTextAlignmentCenter;
  _input.returnKeyType = UIReturnKeyDone;
  _input.delegate = self;
  [authBgview addSubview:_input];
  UIButton *closeBtn = [[UIButton alloc] initWithFrame:CGRectMake(10,170, kScreenWidth-80, 40)];
  [closeBtn addTarget:self action:@selector(removeview) forControlEvents:UIControlEventTouchUpInside];
   = RGBCOLOR(34,151,216);
  [closeBtn setTitle: @"closure" forState: UIControlStateNormal];
  [authBgview addSubview:closeBtn];
  [DomodelView addSubview:authBgview];
   [ addSubview:DomodelView];
//  InvoiceRecordViewController *InvoiceRecordVc = [[InvoiceRecordViewController alloc] initWithNibName:@"InvoiceRecordViewController" bundle:nil];
//  [ pushViewController:InvoiceRecordVc animated:YES];
}
#pragma mark input box proxy, click the return button- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
  //Discern whether the entered is the verification code displayed in the verification picture  if([_input.text compare: options:NSCaseInsensitiveSearch |NSNumericSearch] ==NSOrderedSame)
  {
    // Correct warning message prompt correct    // UIAlertView *alview = [[UIAlertView alloc] initWithTitle:@"Congratulations ^o^" message:@"Verification successful" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];    //    [alview show];
    [DomodelView removeFromSuperview];
    InvoiceRecordViewController *InvoiceRecordVc = [[InvoiceRecordViewController alloc] initWithNibName:@"InvoiceRecordViewController" bundle:nil];
    [ pushViewController:InvoiceRecordVc animated:YES];
  }
  else
  {
    //Verification mismatch, verification code and input box jitter    CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:@""];
     = 1;
     = @[@-20,@20,@-20];
    //    [ addAnimation:anim forKey:nil];
    [_input.layer addAnimation:anim forKey:nil];
  }
  return YES;
}