把UIColor（纯色值）对象转化成UIImage对象

+ (UIImage *)createImageWithColor:(UIColor *)color andSize:(CGSize)size{    CGRect rect=CGRectMake(0.0f, 0.0f, size.width, size.height);    UIGraphicsBeginImageContext(size);    CGContextRef context = UIGraphicsGetCurrentContext();    CGContextSetFillColorWithColor(context, [color CGColor]);    CGContextFillRect(context, rect);        UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();    return theImage;}