我如何完全隐藏这个UIImageView

Question

I have a UITableView with a list of items that can be filtered. When the user chooses a filter, a UIView is exposed using a height NSLayoutConstraint that changes from 0 to 40 pixels:

The circle with the X is the clear button that clears the filter and then closes the UIView by changing the height constraint back to 0.

The problem is that when the UIView closes, that clear button doesn't completely go away:

Here's the relevant code:

class LiftLogViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, NSFetchedResultsControllerDelegate {

  let coreDataStack = CoreDataStack()

  var liftEvents = [LiftEvent]()

  //MARK: IB outlets

  @IBOutlet var tableView: UITableView!
  @IBOutlet weak var navItem: UINavigationItem!
  @IBOutlet weak var filterViewHeightConstraint: NSLayoutConstraint!
  @IBOutlet weak var clearFilterButton: UIImageView!
  @IBOutlet weak var selectedFilter: UILabel!
  @IBOutlet weak var clearButtonHeightConstraint: NSLayoutConstraint!
  @IBOutlet weak var clearButtonView: UIImageView!

  var isFilterViewOpen = false

  override func viewDidLoad() {

    let doneButton = UIBarButtonItem(title: "Done", style: .Plain, target: self, action: #selector(self.dismissLog(_:)))

    let filterImage = UIImage(named: "filter_icon")

    let filterButton = UIBarButtonItem(image: filterImage, style: .Plain, target: self, action: #selector(self.actionFilter))

    self.navItem.rightBarButtonItems = [doneButton, filterButton]

    let buttonTap = UITapGestureRecognizer(target: self, action: #selector(self.clearFilter))

    clearFilterButton.addGestureRecognizer(buttonTap)

    filterViewHeightConstraint.constant = 0.0

    clearButtonHeightConstraint.constant = 0.0

    super.viewDidLoad()
  }


override func viewWillAppear(animated: Bool) {
    let filterPredicate: NSPredicate?
    if let logFilter = UserDefaultsManager.sharedInstance.logFilter?.rawValue {
      filterPredicate = NSPredicate(format: "lift.liftName = [c] %@", logFilter)
      print("viewWillAppear thinks the filter is \(logFilter)")
    } else {
      filterPredicate = nil
    }
    reloadData(filterPredicate)

    let currentFilter = getCurrentLogFilter()

    if currentFilter != nil {
      selectedFilter.text = "Filtered by \(currentFilter!)"
      isFilterViewOpen = true
      clearButtonView.hidden = isFilterViewOpen ? false : true
    } else {
      selectedFilter.text = nil
    }

    super.viewWillAppear(animated)
  }


 override func viewDidAppear(animated: Bool) {
    filterViewHeightConstraint.constant = isFilterViewOpen ? 40.0 : 0.0

    clearButtonHeightConstraint.constant = isFilterViewOpen ? 21.0 : 0.0

    clearButtonView.hidden = isFilterViewOpen ? false : true

    UIView.animateWithDuration(0.33, delay: 0, options: [.CurveEaseOut], animations: {

    self.view.layoutIfNeeded()
        }, completion: nil)
  }


func clearFilter() {
    UserDefaultsManager.sharedInstance.logFilter = nil

    isFilterViewOpen = !isFilterViewOpen

    UIView.animateWithDuration(0.33, delay: 0, options: [.CurveEaseOut], animations: {

      self.view.layoutIfNeeded()
      }, completion: nil)

    selectedFilter.text = nil

    reloadData()
  }

You can see I've tried both setting the .hidden value on the UIView that holds the clear button to true and I've tried changing the height constraint to 0.0 but neither of those make it gone completely.

Searching for a while hasn't produced any answers. Can anybody point out what's wrong with what I'm doing? Thanks.

Answer 1

It seems like the hair line color on the navigation bar may be clear resulting in the button still being slightly visible. Maybe change that and see if it covers the button. You can do so like this:

let view = UIView()
view.backgroundColor = UIColor.grayColor()
self.navigationController!.navigationBar.hairlineImageViewInNavigationBar(view)

Answer 2

As Dustin Spengler mentioned, the transparent hairline image view in the navigation bar causes the filter button to be slightly visible beneath it. As a workaround, you can hide the filter view ( filterView.hidden = true ) when constraint constant is set to 0.0 and unhide the filter view ( filterView.hidden = false ) when constraint constant is set to 40.0.

Answer 3

Thank you guys for your suggestions. It turns out that the solution was a little different, but your suggestions got me to poke around some more in that area and find the solution.

I neglected to mention that this was a view controller that I add a UIStackView that wrapped my UIView (the grey "filtered by" UIView ) and the UITableView :

The problem was that the constraint I created from the top of the UIStackView to the top of its parent view was just slightly too big, pushing the top of the UIStackView just far enough to expose that little sliver. I reduced the Y distance to 63 and it's now perfect:

Thanks again for trying to help.