一，效果图。
二，工程图。
三，代码。
RootViewController.h
RootViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view. self.title=@"背景颜色的随机显示"; }
//点击任何处，变换背景颜色
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
CGFloat red = (CGFloat)arc4random() / 0x100000000;
CGFloat green = (CGFloat)arc4random() / 0x100000000;
CGFloat blue = (CGFloat)arc4random() / 0x100000000;
self.view.backgroundColor = [UIColor colorWithRed:red green:green blue:blue alpha:1.0f];
}