iOS 生成本地验证码

1、导入CoreGraphics.framework

2、为验证码封装一个UIview，在使用的时候直接把这个View加到界面上使用

CaptchaView.h

#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

CaptchaView.m

#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CGContextRef    CGContextRef 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

3、在界面上调用展示验证码

ViewController.m

#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