#import <UIKit/UIKit.h>@interface CaptchaView : UIView@property (nonatomic, retain) NSArray *changeArray; //字符素材数组
@property (nonatomic, retain) NSMutableString *changeString;  //验证码的字符串@end

#import "CaptchaView.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 CaptchaView
@synthesize changeString,changeArray;- (instancetype)initWithFrame:(CGRect)frame
{if (self = [super initWithFrame:frame]) {self.layer.cornerRadius = 5.0; //设置layer圆角半径self.layer.masksToBounds = YES; //隐藏边界self.backgroundColor = kRandomColor;//显示一个随机验证码[self changeCaptcha];}return self;
}
#pragma mark 更换验证码,得到更换的验证码的字符串
-(void)changeCaptcha
{
//<一>从字符数组中随机抽取相应数量的字符，组成验证码字符串//数组中存放的是全部可选的字符，可以是字母，也可以是中文self.changeArray = [[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",@"杰",@"瑞",@"教",@"育",nil];//如果能确定最大需要的容量，使用initWithCapacity:来设置，好处是当元素个数不超过容量时，添加元素不需要重新分配内存NSMutableString *getStr = [[NSMutableString alloc] initWithCapacity:kCharCount];self.changeString = [[NSMutableString alloc] initWithCapacity:kCharCount];//随机从数组中选取需要个数的字符，然后拼接为一个字符串for(int i = 0; i < kCharCount; i++){NSInteger index = arc4random() % ([self.changeArray count] - 1);getStr = [self.changeArray objectAtIndex:index];self.changeString = (NSMutableString *)[self.changeString stringByAppendingString:getStr];}//<2>从网络获取字符串，然后把得到的字符串在本地绘制出来（网络获取步骤在这省略）
//    self.changeString = [NSMutableString stringWithString:@"杰瑞教育"];
}#pragma mark 点击view时调用，因为当前类自身就是UIView，点击更换验证码可以直接写到这个方法中，不用再额外添加手势
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{//点击界面，切换验证码[self changeCaptcha];//setNeedsDisplay调用drawRect方法来实现view的绘制[self setNeedsDisplay];
}#pragma mark 绘制界面（1.UIView初始化后自动调用； 2.调用setNeedsDisplay方法时会自动调用）
- (void)drawRect:(CGRect)rect {// 重写父类方法，首先要调用父类的方法[super drawRect:rect];//设置随机背景颜色self.backgroundColor = kRandomColor;//获得要显示验证码字符串，根据长度，计算每个字符显示的大概位置NSString *text = [NSString stringWithFormat:@"%@",self.changeString];CGSize cSize = [@"S" 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CGContextRefCGContextRef context = UIGraphicsGetCurrentContext();//设置画线宽度CGContextSetLineWidth(context, kLineWidth);//绘制干扰的彩色直线for(int i = 0; i < kLineCount; i++){//设置线的随机颜色UIColor *color = kRandomColor;CGContextSetStrokeColorWithColor(context, [color CGColor]);//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

#import "ViewController.h"
#import "CaptchaView.h"@interface ViewController ()<UITextFieldDelegate,UIAlertViewDelegate>
{CaptchaView *_captchaView;UITextField *_input;
}@end@implementation ViewController- (void)viewDidLoad {[super viewDidLoad];//显示验证码界面_captchaView = [[CaptchaView alloc] initWithFrame:CGRectMake(20, 40, 150, 40)];[self.view addSubview:_captchaView];//提示文字UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(190, 40, 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(20, 100, 150, 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 输入框协议中方法,点击return按钮
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{//判断输入的是否为验证图片显示的验证码if ([_input.text isEqualToString:_captchaView.changeString]) {//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，验证码和输入框晃动CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:@"transform.translation.x"];anim.repeatCount = 1;anim.values = @[@-20, @20, @-20];[_captchaView.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];}
}
@end

作者： 杰瑞教育
出处： http://blog.csdn.net/jerehedu
本文版权归烟台杰瑞教育科技有限公司和CSDN共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。