IOS-验证码的实现和封装（可以直接调用）

最近对OC中的图像比较感兴趣。随手搞得一个类似验证码的demo。直接贴代码了。

小demo中的VerificationCodeView是继承自UIView的，所以需要用到的时候，可以直接定义一个UIView，addSubviews就可以了。还是挺方便的。哈哈😄

小demo中的#define kCharCount 表示显示几个验证字符的。这个自己可以根据自己的需要自己定义。

小弟刚接触图像绘制，不足之处，余生请多指教

Life-long learning ...

#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 VerificationCodeView
@synthesize verificationCodeStr,verificationCodeArray;

- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        
        self.layer.cornerRadius = 5.0; 
        self.layer.masksToBounds = YES; 
        self.backgroundColor = kRandomColor;
        
        //显示一个随机验证码
        [self changeCaptcha];
    }
    
    return self;
}

//获取验证码
-(void)changeCaptcha
{
    self.verificationCodeArray = [[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];
    
    NSMutableString *getStr = [[NSMutableString alloc] initWithCapacity:kCharCount];
    self.verificationCodeStr = [[NSMutableString alloc] initWithCapacity:kCharCount];
    
    for(int i = 0; i < kCharCount; i++)
    {
        NSInteger index = arc4random() % ([self.verificationCodeArray count] - 1);
        getStr = [self.verificationCodeArray objectAtIndex:index];
        
        self.verificationCodeStr = (NSMutableString *)[self.verificationCodeStr stringByAppendingString:getStr];
    }
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    //切换验证码
    [self changeCaptcha];
    
    //setNeedsDisplay调用drawRect方法来实现view的绘制
    [self setNeedsDisplay];
}

- (void)drawRect:(CGRect)rect {
    [super drawRect:rect];
    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.verificationCodeStr];
    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();
    CGContextSetLineWidth(context, kLineWidth);
    
    //绘制干扰的彩色直线
    for(int i = 0; i < kLineCount; i++)
    {
        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);
    }
}

小弟，稍后会将源文件传到GitHub上。