iOS本地动态验证码生成

用于ios本地动态生成验证码，效果如下：

• 导入CoreGraphics.framework
  用于绘制图形

• 封装UIView，便捷使用，代码如下：

AuthcodeView.h

#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

#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 6
#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

• 界面添加验证码

@interface AuthCodeViewController ()<UITextFieldDelegate, UIAlertViewDelegate>
{
    AuthcodeView *authCodeView;
    UITextField *_input;
}

@end

@implementation AuthCodeViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    self.view.backgroundColor = [UIColor whiteColor];
    
    //显示验证码界面
    authCodeView = [[AuthcodeView alloc] initWithFrame:CGRectMake(30, 100, self.view.frame.size.width-60, 40)];
    [self.view addSubview:authCodeView];
    
    //提示文字
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(50, 160, self.view.frame.size.width-100, 40)];
    label.text = @"点击图片换验证码";
    label.font = [UIFont systemFontOfSize:12];
    label.textColor = [UIColor grayColor];
    [self.view addSubview:label];

    //添加输入框
    _input = [[UITextField alloc] initWithFrame:CGRectMake(30, 220, self.view.frame.size.width-60, 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;
    [self.view addSubview:_input];
}

#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 isEqualToString:authCodeView.authCodeStr])
    {
        //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];
    }
    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;
}

#pragma mark 警告框中方法
-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    //清空输入框内容，收回键盘
    if (buttonIndex==0)
    {
        _input.text = @"";
        [_input resignFirstResponder];
    }
}