iOS动态验证码如何实现代码

//
// AuthcodeView.h
// BSbracelet
//
// Created by Christopher on 17/5/16.
// Copyright © 2017年 ZTracy. All rights reserved.
//
#import <UIKit/UIKit.h>
@interface AuthcodeView : UIView
@property (strong, nonatomic) NSArray *dataArray;//字符素材数组
@property (strong, nonatomic) NSMutableString *authCodeStr;//验证码字符串
@end
//
// AuthcodeView.m
// BSbracelet
//
// Created by Christopher on 17/5/16.
// Copyright © 2017年 ZTracy. All rights reserved.
//
#import "AuthcodeView.h"
#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)
  {
    self.layer.cornerRadius = 5.0f;
    self.layer.masksToBounds = YES;
    self.backgroundColor = kRandomColor;
    [self getAuthcode];//获得随机验证码
  }
  return self;
}
#pragma mark 获得随机验证码
- (void)getAuthcode
{
  //字符串素材
  _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];
  //随机从数组中选取需要个数的字符串，拼接为验证码字符串
  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 点击界面切换验证码
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
  [self getAuthcode];
  //setNeedsDisplay调用drawRect方法来实现view的绘制
  [self setNeedsDisplay];
}
- (void)drawRect:(CGRect)rect
{
  [super drawRect:rect];
  //设置随机背景颜色
  self.backgroundColor = kRandomColor;
  //根据要显示的验证码字符串，根据长度，计算每个字符串显示的位置
  NSString *text = [NSString stringWithFormat:@"%@",_authCodeStr];
  CGSize cSize = [@"A" sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:20]}];
  int width = rect.size.width/text.length - cSize.width;
  int height = rect.size.height - cSize.height;
  CGPoint point;
  //依次绘制每一个字符,可以设置显示的每个字符的字体大小、颜色、样式等
  float pX,pY;
  for ( int i = 0; i<text.length; i++)
  {
    pX = arc4random() % width + rect.size.width/text.length * 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}];
  }
  //调用drawRect：之前，系统会向栈中压入一个CGContextRef，调用UIGraphicsGetCurrentContext()会取栈顶的CGContextRef
  CGContextRef context = UIGraphicsGetCurrentContext();
  //设置线条宽度
  CGContextSetLineWidth(context, kLineWidth);
  //绘制干扰线
  for (int i = 0; i < kLineCount; i++)
  {
    UIColor *color = kRandomColor;
    CGContextSetStrokeColorWithColor(context, color.CGColor);//设置线条填充色
    //设置线的起点
    pX = arc4random() % (int)rect.size.width;
    pY = arc4random() % (int)rect.size.height;
    CGContextMoveToPoint(context, pX, pY);
    //设置线终点
    pX = arc4random() % (int)rect.size.width;
    pY = arc4random() % (int)rect.size.height;
    CGContextAddLineToPoint(context, pX, pY);
    //画线
    CGContextStrokePath(context);
  }
}
@end
使用
-(void)recordBtnClick:(UIButton *)recordBtn
{
  DomodelView = [[UIView alloc]initWithFrame:CGRectMake(0,0,kScreenWidth,kScreenHeight)];
  DomodelView.backgroundColor = [UIColor colorWithRed:0.3 green:0.3 blue:0.3 alpha:0.6];
  authBgview = [[UIView alloc]initWithFrame:CGRectMake(30, 120, self.view.frame.size.width-60, 220)];
  authBgview.backgroundColor = [UIColor whiteColor]; //显示验证码界面
  authBgview.layer.cornerRadius = 8;
  authBgview.layer.masksToBounds = YES;
  authCodeView = [[AuthcodeView alloc] initWithFrame:CGRectMake(10, 10, kScreenWidth-80, 45)];
  [authBgview addSubview:authCodeView];
    //提示文字
  UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(10, 65, kScreenWidth-80, 40)];
  label.text = @"点击图片换验证码";
  label.font = [UIFont systemFontOfSize:15];
  label.textColor = [UIColor grayColor];
  [authBgview addSubview:label];
  //添加输入框
  _input = [[UITextField alloc] initWithFrame:CGRectMake(10, 120, kScreenWidth-80, 40)];
  _input.layer.borderColor = [UIColor lightGrayColor].CGColor;
  _input.layer.borderWidth = 2.0;
  _input.layer.cornerRadius = 5.0;
  _input.font = [UIFont systemFontOfSize:21];
  _input.placeholder = @"请输入验证码!";
  _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];
  closeBtn.backgroundColor = RGBCOLOR(34,151,216);
  [closeBtn setTitle: @"关闭" forState: UIControlStateNormal];
  [authBgview addSubview:closeBtn];
  [DomodelView addSubview:authBgview];
   [self.view addSubview:DomodelView];
//  InvoiceRecordViewController *InvoiceRecordVc = [[InvoiceRecordViewController alloc] initWithNibName:@"InvoiceRecordViewController" bundle:nil];
//  [self.navigationController pushViewController:InvoiceRecordVc animated:YES];
}
#pragma mark 输入框代理，点击return 按钮
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
  //判断输入的是否为验证图片中显示的验证码
  if([_input.text compare:authCodeView.authCodeStr options:NSCaseInsensitiveSearch |NSNumericSearch] ==NSOrderedSame)
  {
    //正确弹出警告款提示正确
    //    UIAlertView *alview = [[UIAlertView alloc] initWithTitle:@"恭喜您 ^o^" message:@"验证成功" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
    //    [alview show];
    [DomodelView removeFromSuperview];
    InvoiceRecordViewController *InvoiceRecordVc = [[InvoiceRecordViewController alloc] initWithNibName:@"InvoiceRecordViewController" bundle:nil];
    [self.navigationController pushViewController:InvoiceRecordVc animated:YES];
  }
  else
  {
    //验证不匹配，验证码和输入框抖动
    CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:@"transform.translation.x"];
    anim.repeatCount = 1;
    anim.values = @[@-20,@20,@-20];
    //    [authCodeView.layer addAnimation:anim forKey:nil];
    [_input.layer addAnimation:anim forKey:nil];
  }
  return YES;
}