ios中的滑动

@interface ViewController ()<UIScrollViewDelegate>
@property (nonatomic, strong) TestScrollView *scr1;
@property (nonatomic, strong) UIScrollView *scr2;
@end
@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    [self.view addSubview:self.scr1];
}
- (UIScrollView *)scr1 {
    if (!_scr1) {
        _scr1 = [[UIScrollView alloc] init];
        CGFloat width = [UIScreen mainScreen].bounds.size.width;
        CGFloat height = [UIScreen mainScreen].bounds.size.height;
        _scr1.frame = CGRectMake(0, 0, width, height);
        _scr1.backgroundColor = [UIColor orangeColor];
        _scr1.contentSize = CGSizeMake(width * 2, height);
        _scr1.pagingEnabled = YES;
        _scr1.delegate = self;
        [_scr1 addSubview:self.scr2];
    }
    return _scr1;
}
- (UIScrollView *)scr2 {
    if (!_scr2) {
        _scr2 = [[UIScrollView alloc] init];
        CGFloat width = [UIScreen mainScreen].bounds.size.width;
        CGFloat height = [UIScreen mainScreen].bounds.size.height;
        _scr2.frame = CGRectMake(0, 50, width, height - 50);
        _scr2.backgroundColor = [UIColor blueColor];
        _scr2.contentSize = CGSizeMake(width * 2, 0);
        _scr2.pagingEnabled = YES;
        _scr2.delegate = self;
    }
    return _scr2;
}
@end