How to get touch coordinates upon SELECTING a cust

问题:

When I touch (Touch Up) a UITableViewCell my ViewController's UITableViewDelegate method - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath is called. I need to get the x-coordinate of the Touch-Point at this time as well so that I can know what portion of the Cell was touched (non-accessory items). I have tried using the usual touch methods such as TouchesDidEnd but the coordinates always return x=0.000 y=0.000 no matter where I touched (A location in a custom UITableViewCell in a UITableView object in my ViewController). I also tried implementing touch handling from within the Custom Cell class and while I COULD get accurate coordinates alas I could find no way to communicate those coordinates to my ViewController class (which has the UITableView).

Q: Is there a good way I can get the x-coordinates of the device's screen when I touch a custom UITableViewCell?

回答1:

Put a transparent UIView atop your table view, override its -touchesBegan:withEvent: etc. methods. In those overridden methods, get the UITouch objects and call -locationInView: on them to get the CGPoint values.

That gives you the coordinates of a touch event.

Then you just pass on those UITouch events to the underlying table view. The table view handles its usual business of passing touches on to rows, etc.

回答2:

1. Add a tapGestureRecognizer to your tableView

let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(self.tableViewTapped(recognizer:)))
tableView.addGestureRecognizer(tapGestureRecognizer)

2. Write a function to handle the tapGesture

@objc func tableViewTapped(recognizer: UITapGestureRecognizer) {
    let location = recognizer.location(in: self.tableView) // point of touch in tableView
    if let indexPath = self.tableView.indexPathForRow(at: location) { // indexPath of touch location
        if let cell = tableView.cellForRow(at: indexPath) as? MyCustomCell {
            let locationInCell = recognizer.location(in: cell) // point of touch in cell
            // do something with location or locationInCell

            if cell.imageView.frame.contains(location) || cell.imageView.frame.contains(locationInCell) {
                    print("ImageView inside cell tapped!")        
            }
        }
    }
}

回答3:

1) Pass view controller object in the custom cell

class ImageTableViewCell: UITableViewCell {

      @IBOutlet weak var img: UIImageView!

      var vc: UIViewController? = nil

      var delegate: TouchLocation?

}

2) Override the custom table view cell with touchesBegan method, and override super touchesBegan method

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    let touch = touches.first
    delegate?.touchLocation(location: (touch?.location(in: self.vc?.view))!)
    if let aTouches = touches as? Set<UITouch>, let anEvent = event {
        super.touchesBegan(aTouches, with: anEvent)
    }
}

3) Get location and pass to view controller using delegation

protocol TouchLocation {
   func touchLocation(location: CGPoint)
}

extension ImageListViewController: TouchLocation{

   func touchLocation(location: CGPoint) {
         self.touchedPosition = location // Here you will get touch location 
   }

}

回答4:

What about :

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

        let rect = tableView.rectForRow(at: indexPath as IndexPath)
        var point = CGPoint(x: rect.midX, y: rect.midY)
        point = tableView.convert(point, to: nil)
        print(point)
}