Hiding aUITableView in UIScrollView using UIKit

As a developer, we’ve all encountered situations where we need to hide or reveal certain elements based on user interaction. In this article, we’ll explore how to achieve this by hiding a UITableView within a UIScrollView. We’ll delve into the details of UITapGestureRecognizer, UIScrollViewDelegate, and other relevant concepts to provide a comprehensive understanding of the solution.

Understanding UIScrollView and UITableView

A UIScrollView is a view that allows users to scroll through its content. It’s commonly used in applications where there’s more content than can be displayed on screen at once, such as lists or grids. On the other hand, a UITableView is a table-like control that displays data in rows and columns.

The Problem

In our scenario, we have a UIScrollView containing a button, which when tapped, generates a UITableView. However, we want to hide this table when the user touches anywhere on the scroll view. We’ve tried using touchesBegan:withEvent: and UITapGestureRecognizer, but neither approach seems to be working as expected.

Solution: Adding an Overlay View

One way to achieve this is by adding an overlay view behind the table view. This overlay view will serve as a “mask” that hides the table when touched, allowing us to reveal it again when necessary. We’ll use UITapGestureRecognizer to recognize touches on this overlay view.

Step 1: Add an Overlay View

Create a new view (e.g., overlayView) with a clear background color. This will serve as our mask for hiding the table.

{< highlight objective-c >
@interface OverlayView : UIView

@end
</highlight>}

In your code, create and add this overlay view to your scroll view:

UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height)];
// Add the overlay view behind the table view
UIView *overlayView = [[OverlayView alloc] initWithFrame:scrollView.bounds];
overlayView.backgroundColor = [UIColor clearColor];
[scrollView addSubview:overlayView];

// Configure the scroll view
scrollView.delegate = self;
scrollView.contentSize = CGSizeMake(0, 1000); // adjust as needed

[self.view addSubview:scrollView];

Step 2: Implement UITapGestureRecognizer

Implement UITapGestureRecognizer on the overlay view to recognize touches:

{< highlight objective-c >
- (void)viewDidLoad {
    [super viewDidLoad];

    UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(hideTableView)];
    tapGestureRecognizer.numberOfTapsRequired = 1;
    [overlayView addGestureRecognizer:tapGestureRecognizer];
}

- (void)hideTableView {
    // Hide the table view
    [tableView setHidden:YES];
}

In this code, when the user taps on the overlay view, we call hideTableView to hide the table.

Step 3: Reveal the Table View

When the user lifts their finger from the overlay view or navigates away from it, we want to reveal the table view. We can achieve this by calling showTableView:

- (void)revealTableView {
    // Show the table view
    [tableView setHidden:NO];
}

Step 4: Configure UIScrollViewDelegate

To recognize when the user touches anywhere on the scroll view, we need to implement UIScrollViewDelegate. In the delegate’s implementation, we’ll check if the touch is within the bounds of the overlay view and hide the table accordingly:

{< highlight objective-c >
- (void)scrollViewDidTouch:(UIScrollView *)scrollView {
    CGPoint location = [scrollView pointInside touchesFirstAtPoint:self.view.frame.size.width / 2];
    
    if ([location x] < overlayView.frame.origin.x + overlayView.bounds.size.width &&
        [location y] < overlayView.frame.origin.y + overlayView.bounds.size.height) {
        // Hide the table view
        [tableView setHidden:YES];
    } else {
        // Reveal the table view
        [tableView setHidden:NO];
    }
}

In this code, we check if the touch is within the bounds of the overlay view. If it is, we hide the table; otherwise, we reveal it.

Conclusion

By adding an overlay view behind the table view and implementing UITapGestureRecognizer, we can effectively hide the table when the user touches anywhere on the scroll view. This solution provides a clean and intuitive way to manage visibility of UI elements based on user interaction.

Last modified on 2025-02-04