scrollview背景

当scrollview不设置背景色时，拖动scrollview上的内容，边界显示view的背景色。

当scrollview设置背景色时，拖动scrollview上的内容，边界显示scrollview的背景色

用两种颜色时，可以在scrollview上再添加一层，如黄色的view。

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
    //CGFloat w = self.view.frame.size.width;
    //CGFloat h = self.view.frame.size.height;
    int w = self.view.bounds.size.width;
    int h = self.view.bounds.size.height;

    self.view.backgroundColor = [UIColor redColor];

    _scrollView = [[UIScrollView alloc]initWithFrame:self.view.frame];
    _scrollView.backgroundColor = [UIColor blueColor];

    [self.view addSubview:_scrollView];

    UIView *view = [[UIView alloc]initWithFrame:self.view.frame];
    [_scrollView addSubview: view];

    view.backgroundColor = [UIColor yellowColor];

    for(int i = 0;i< kCount;i++)
    {

        NSString *name = [NSString stringWithFormat:@"%02d.jpg",i+1];
        UILabel *label = [[UILabel alloc] init];
        label.frame = CGRectMake(i*w, 0, w, h);
        label.text = name;
        [view addSubview:label];

    }

    _scrollView.userInteractionEnabled = YES;

    _scrollView.contentSize = CGSizeMake(kCount*w, 800);// height == 0 代表 禁止垂直方向滚动
    _scrollView.scrollEnabled = YES;
    _scrollView.pagingEnabled = YES;

    _scrollView.delegate = self;

}