附上代码，类似于注册网站上的验证码
付图：
- (void)change
{
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",nil];
NSMutableString *getStr = [[NSMutableString alloc] initWithCapacity:5];
self.changeString = [[NSMutableString alloc] initWithCapacity:6];
for(NSInteger i = 0; i < 4; i++)
{
NSInteger index = arc4random() % ([self.changeArray count] - 1);
getStr = [self.changeArray objectAtIndex:index];
self.changeString = (NSMutableString *)[self.changeString stringByAppendingString:getStr];
}
}
- (void)drawRect:(CGRect)rect {
[super drawRect:rect];
float red = arc4random() % 100 / 100.0;
float green = arc4random() % 100 / 100.0;
float blue = arc4random() % 100 / 100.0;
UIColor *color = [UIColor colorWithRed:red green:green blue:blue alpha:1.0];
[self setBackgroundColor:color];
NSString *text = [NSString stringWithFormat:@"%@",self.changeString];
CGSize cSize = [@"S" sizeWithFont:[UIFont systemFontOfSize:20]];
int width = rect.size.width / text.length - cSize.width;
int height = rect.size.height - cSize.height;
CGPoint point;
float pX, pY;
for (int i = 0; i < text.length; i++)
{
NSLog(@"rect.size.width / text.length * i%f",rect.size.width / 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 withFont:[UIFont systemFontOfSize:20]];
}
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 1.0);
for(int cout = 0; cout < 10; cout++) {
red = arc4random() % 100 / 100.0;
green = arc4random() % 100 / 100.0;
blue = arc4random() % 100 / 100.0;
color = [UIColor colorWithRed:red green:green blue:blue alpha:1.0];
CGContextSetStrokeColorWithColor(context, [color CGColor]);
pX = arc4random() % (int)rect.size.width;
pY = arc4random() % (int)rect.size.height;
CGContextMoveToPoint(context, pX, pY);
pX = arc4random() % (int)rect.size.width;
pY = arc4random() % (int)rect.size.height;
CGContextAddLineToPoint(context, pX, pY);
CGContextStrokePath(context);
}
}