Transfer Gestures on a Uiview to a Uitableview in Swift - iOS

Transfer gestures on a UIView to a UITableView in Swift - iOS

That's Tricky

What is problem ?

Your top view is not allowed to pass through view behind it...

What would be possible solutions

1. pass all touches to view behind it (Seems to not possible or very tough practically )
2. Tell window to ignore touches on top view (Easy one)

Second option is better and easy.

So What you need to do is create subclass of UIView and override

 override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView?  

and return nil if you found same view on hitTest action

Here Tested and working example

class PassThroughME : UIView {
    override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
        return super.hitTest(point, with: event) == self ? nil : self
    }
}

That's it now use PassThroughME either by adding class to your view in storyboard or programmatically whatever way you have added your view

Check image i have black color view with 0.7 alpha on top still i am able to scroll

Hope it is helpful

Passing vertical scrolling gesture to UITableView below

I just solved a similar problem, except it was for vertical pans instead of horizontal ones. I'm not 100% sure about your use case, so this may not be what your looking for, but it may lead you in the right direction.

I sub-classed UIPanGestureRecognizer, and implemented the touchesMoved method, and checked to see whether the gesture had a larger horizontal or vertical change. Below is a snippet. The credit belongs to a different stackoverflow post, but I cannot find the link at the moment. (Sorry in advance for the poor formatting, first time posting)

-(void)touchesMoved:(NSSet*) touches withEvent:(UIEvent *)event
{
[super touchesMoved:touches withEvent:event];
if(self.state == UIGestureRecognizerStateFailed) return;
CGPoint currentPoint = [[touches anyObject] locationInView:self.view];
CGPoint prevPoint = [[touches anyObject] previousLocationInView:self.view];
moveX += prevPoint.x - currentPoint.x;
moveY += prevPoint.y - currentPoint.y;
if(!drag) {
    if(abs(moveY) > abs(moveX))
        drag = YES;
    else
        self.state = UIGestureRecognizerStateFailed;
}
}

-(void)reset
{
[super reset];
drag = NO;
moveX = 0;
moveY = 0;
}

In my parent view controller, which I believe would be the UITableView in this case, I also implemented the following. I think in your case, you'd want to return no if it's a horizontal pan.

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
if([gestureRecognizer isKindOfClass:[VerticalPanGestureRecognizer class]])
{
    return YES;
}
return NO;
}

Let me know if any of this is unclear.

Good Luck!

How to add gesture to UITableViewCell?

To add gesture to UITableViewCell, you can follow the steps below:

First, add gesture recognizer to UITableView

tapGesture = UITapGestureRecognizer(target: self, action: #selector(tableViewController.tapEdit(_:)))
tableView.addGestureRecognizer(tapGesture!)
tapGesture!.delegate = self

Then, define the selector. Use recognizer.locationInView to locate the cell you tap in tableView. And you can access the data in your dataSource by tapIndexPath, which is the indexPath of the cell the user tapped.

func tapEdit(recognizer: UITapGestureRecognizer)  {
    if recognizer.state == UIGestureRecognizerState.Ended {
        let tapLocation = recognizer.locationInView(self.tableView)
        if let tapIndexPath = self.tableView.indexPathForRowAtPoint(tapLocation) {
            if let tappedCell = self.tableView.cellForRowAtIndexPath(tapIndexPath) as? MyTableViewCell {
                //do what you want to cell here

            }
        }
    }
}

It is possible to add gesture directly to TableView cell and access the datasource in viewController, You need to set up a delegate:

In your custom cell:

import UIKit

class MyTableViewCell: UITableViewCell {

    var delegate: myTableDelegate?

    override func awakeFromNib() {
        super.awakeFromNib()

        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(MyTableViewCell.tapEdit(_:)))
        addGestureRecognizer(tapGesture)
        //tapGesture.delegate = ViewController()

    }

    func tapEdit(sender: UITapGestureRecognizer) {
        delegate?.myTableDelegate()
    }

}

protocol myTableDelegate {
    func myTableDelegate() 
}

In your viewController:

import UIKit

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, UIGestureRecognizerDelegate, myTableDelegate {

    @IBOutlet var tableView: UITableView!

    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.delegate = self
        tableView.dataSource = self
        // Do any additional setup after loading the view, typically from a nib.
    }

    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 35
    }

    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as? MyTableViewCell

        cell?.delegate = self

        return cell!
    }

    func myTableDelegate() {
        print("tapped")
        //modify your datasource here
    }

}

However, this method could cause problems, see UIGestureRecognizer and UITableViewCell issue. In this case, when the swipe gesture successes, the selector get called twice for some reason. I can't say the second method is a bad one as I haven't found any direct evidence yet, but after searching through Google, it seems like the first method is the standard way.

UITapGestureRecognizer breaks UITableView didSelectRowAtIndexPath

Ok, finally found it after some searching through gesture recognizer docs.

The solution was to implement UIGestureRecognizerDelegate and add the following:

#pragma mark UIGestureRecognizerDelegate methods
    
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
  if ([touch.view isDescendantOfView:autocompleteTableView]) {
            
    // Don't let selections of auto-complete entries fire the 
    // gesture recognizer
    return NO;
  }
        
  return YES;
}

That took care of it. Hopefully this will help others as well.

---

Related Topics