Disable diagonal dragging in UIScrollview

问题:

I am using UIScrollview to load my two views let say A and B. It exactly looks like the below picture. I set PagingEnabled as YES and DirectionLockEnabled as YES.

When I drag the view from A to B it goes diagonally. Please find the code below,

- (void)setupScrollView:(UIScrollView*)scrMain {

    for (int i = 0; i < 2; i++) {
        if (i == 0) {
            // View A
            [ViewA setFrame:CGRectMake((i)*scrollview.frame.size.width + 20, 0, scrollview.frame.size.width - 40, ViewA.frame.size.height)];
            [scrollview addSubview:ViewA];
        } else if (i == 1) {
           // View B
           [ViewB setFrame:CGRectMake((i)*ViewB.frame.size.width + 30, 0, scrollview.frame.size.width - 40, ViewB.frame.size.height)];
           [scrollview addSubview:ViewB];
        }
    }
    [scrollview setContentSize:CGSizeMake((scrollview.frame.size.width-15)*2, ViewB.frame.size.height)];
}

- (void) scrollViewWillBeginDragging: (UIScrollView *) scrollView
{
    self.oldContentOffset = scroller.contentOffset;
}

- (void) scrollViewDidScroll: (UIScrollView *) scrollView
{
    float XOffset = fabs(self.oldContentOffset.x - scrollView.contentOffset.x );
    float YOffset = fabs(self.oldContentOffset.y - scrollView.contentOffset.y );

    if (scrollView.contentOffset.x != self.oldContentOffset.x && (XOffset >= YOffset) )
    {
        scrollView.pagingEnabled = YES;
        scrollDirection = ScrollDirectionHorizontal;
    }
    else
    {
        scrollView.pagingEnabled = NO;
        scrollDirection = ScrollDirectionVertical;
    }

}

I check with these following links but I did't get a solution yet, http://bogdanconstantinescu.com/blog/proper-direction-lock-for-uiscrollview.html UIScrollView scrolling in only one direction at a time http://chandanshetty01.blogspot.ae/2012/07/restricting-diagonal-scrolling-in.html

All Helps are appreciated!!

回答1:

set directionalLockEnabled = YES; after you reset the contentSize of the scrollview

[self.scrollView setContentSize:CGSizeMake((self.scrollView.frame.size.width-15)*2, self.ViewB.frame.size.height)];
self.scrollView.directionalLockEnabled = YES; // add this here.

By doing like this, it will fix your issue

Answer based on your code

- (void)viewDidLoad {
    [super viewDidLoad];
    [self setupScrollView:self.scrollView];
    self.scrollView.directionalLockEnabled = YES;
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


- (void)setupScrollView:(UIScrollView*)scrMain {

for (int i = 0; i < 2; i++) {
    if (i == 0) {
        // View A
        self.ViewA = [[UIView alloc] init];
        self.ViewA.backgroundColor = [UIColor blackColor];
        [self.ViewA setFrame:CGRectMake((i)*self.scrollView.frame.size.width + 20, 0, self.scrollView.frame.size.width - 40, 800)];
        [self.scrollView addSubview:self.ViewA];
    } else if (i == 1) {
        // View B
        self.ViewB = [[UIView alloc] init];
        self.ViewB.backgroundColor = [UIColor blueColor];
        [self.ViewB setFrame:CGRectMake((i)*self.ViewA.frame.size.width + 30, 0, self.scrollView.frame.size.width - 40, 800)];
        [self.scrollView addSubview:self.ViewB];
    }
}
[self.scrollView setContentSize:CGSizeMake((self.scrollView.frame.size.width-15)*2, self.ViewB.frame.size.height)];
self.scrollView.directionalLockEnabled = YES;
}