随机颜色

 self.view.backgroundColor = [UIColor randomColor];

//随机颜色
+(UIColor*)randomColor
{
    NSInteger aRedValue =arc4random() %255;
    NSInteger aGreenValue =arc4random() %255;
    NSInteger aBlueValue =arc4random() %255;
    UIColor *randColor = [UIColor colorWithRed:aRedValue /255.0f green:aGreenValue /255.0f blue:aBlueValue /255.0f alpha:1.0f];
    return randColor;
}