iOS开发-随机图片验证码

在iOS项目中登录注册经常会用到随机验证码，尤其是以图片形式生成的验证码，可以减少使用第三方资源的代码使用，只在本地生成并验证即可，本文即介绍生成随机图片验证码的流程，验证码包括阿拉伯数字0-9，英文大写字母A-Z，英文小写字母a-z，生成的验证码区分大小写。若想改成不区分大小写，只需要在取码的时候添加判断即可。

一、首先创建一个继承自UIView的类，在.h文件中添加外界需要的属性和方法：

@property (strong, nonatomic) NSMutableString *authCodeStr;//验证码字符串- (void)getAuthcode;

二、在.m文件中添加宏定义：

包括验证码选择框背景颜色，干扰线随机颜色，干扰线数量，干扰线宽度，验证码数量，验证码大小

//背景随机颜色#define kRandomColorAL  [UIColor colorWithRed:arc4random() % 256 / 256.0 green:arc4random() % 256 / 256.0 blue:arc4random() % 256 / 256.0 alpha:0.5];//干扰线随机颜色#define kRandomColor  [UIColor colorWithRed:arc4random() % 256 / 256.0 green:arc4random() % 256 / 256.0 blue:arc4random() % 256 / 256.0 alpha:1];//干扰线数量#define kLineCount 4//干扰线宽度#define kLineWidth 1.0//验证码数量#define kCharCount 4//验证码大小#define kFontSize (arc4random() % 5 + 20)

三、初始化：

- (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;}

四、获取随机验证码方法：

#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];    }}

五、点击界面切换验证码：

#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];}

六、绘制：

#pragma mark 绘制- (void)drawRect:(CGRect)rect{    [super drawRect:rect];        //设置随机背景颜色    self.backgroundColor = kRandomColorAL;        //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];        UIFontDescriptor *attributeFontDescriptor = [UIFontDescriptor fontDescriptorWithFontAttributes:                                                     @{UIFontDescriptorFamilyAttribute: @"Marion",                                                       UIFontDescriptorNameAttribute:@"HanziPenSC-W3",                                                       UIFontDescriptorSizeAttribute: @40.0,                                                       UIFontDescriptorMatrixAttribute:[NSValue valueWithCGAffineTransform:CGAffineTransformMakeRotation(M_1_PI*(arc4random() % 2 ))                                                                                        ]}];        UIFont * font = [UIFont fontWithDescriptor:attributeFontDescriptor size:kFontSize];        UIColor *color = kRandomColor;        [textC drawAtPoint:point withAttributes:@{NSFontAttributeName:font,NSForegroundColorAttributeName:color}];            }            //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);    }}

七、调用，在需要使用验证码的类中调用：

1、定义属性：

@property (nonatomic, strong) MaxAuthCodeView * authcodeImage;/**< 验证码视图*/

2、初始化：

self.authcodeImage = [[MaxAuthCodeView alloc] initWithFrame:CGRectMake(50, 100, 120, 60)];    [self.view addSubview:self.authcodeImage];    [self.authcodeImage getAuthcode];

3、获取验证码：

NSLog(@"%@",self.authcodeImage.authCodeStr);

八、希望各位能够获取到有用的信息，谢谢！

demo下载地址：https://github.com/MaxLi7681/AuthCode