UITextView with Gesture Recognizer - Conditionally Forward Touch to Parent View - ios

I have a UITextView embedded in a UITableViewCell.
The text view has scrolling disabled, and grows in height with the text in it.
The text view has a link-like section of text that is attributed with a different color and underlined, and I have a tap gesture recognizer attached to the text view that detects whether the user tapped on the "link" portion of the text or not (This is accomplished using the text view's layoutManager and textContainerInset to detect whether the tap falls within the 'link' or not. It's basically a custom hit test function).
I want the table view cell to receive the tap and become selected when the user "misses" the link portion of the text view, but can't figure out how to do it.
The text view has userInteractionEnabled set to true. However, this does not block the touches from reaching the table view cell when there is no gesture recognizer attached.
Conversely, if I set it to false, for some reason cell selection stops altogether, even when tapping outside of the text view's bounds (but the gesture recognizer still works... WHY?).
What I've Tried
I have tried overriding gestureRecognizer(_ :shouldReceive:), but even when I return false, the table view cell does not get selected...
I have also tried implementing gestureRecognizerShouldBegin(_:), but there too, even if I perform my hit test and return false, the cell does not get the tap.
How can I forward the missed taps back to the cell, to highlight it?

After trying Swapnil Luktuke's answer(to the extent that I understood it, at least) to no avail, and every possible combination of:
Implementing the methods of UIGestureRecognizerDelegate,
Overriding UITapGestureRecognizer,
Conditionally calling ignore(_:for:), etc.
(perhaps in my desperation I missed something obvious, but who knows...)
...I gave up and decided to follow the suggestion by #danyapata in the comments to my question, and subclass UITextView.
Partly based on code found on this Medium post, I came up with this UITextView subclass:
import UIKit
/**
Detects taps on subregions of its attributed text that correspond to custom,
named attributes.
- note: If no tap is detected, the behavior is equivalent to a text view with
`isUserInteractionEnabled` set to `false` (i.e., touches "pass through"). The
same behavior doesn't seem to be easily implemented using just stock
`UITextView` and gesture recognizers (hence the need to subclass).
*/
class LinkTextView: UITextView {
private var tapHandlersByName: [String: [(() -> Void)]] = [:]
/**
Adds a custom block to be executed wjhen a tap is detected on a subregion
of the **attributed** text that contains the attribute named accordingly.
*/
public func addTapHandler(_ handler: #escaping(() -> Void), forAttribute attributeName: String) {
var handlers = tapHandlersByName[attributeName] ?? []
handlers.append(handler)
tapHandlersByName[attributeName] = handlers
}
// MARK: - Initialization
override init(frame: CGRect, textContainer: NSTextContainer?) {
super.init(frame: frame, textContainer: textContainer)
commonSetup()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func awakeFromNib() {
super.awakeFromNib()
commonSetup()
}
private func commonSetup() {
self.delaysContentTouches = false
self.isScrollEnabled = false
self.isEditable = false
self.isUserInteractionEnabled = true
}
// MARK: - UIView
override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
guard let attributeName = self.attributeName(at: point), let handlers = tapHandlersByName[attributeName], handlers.count > 0 else {
return nil // Ignore touch
}
return self // Claim touch
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesEnded(touches, with: event)
// find attribute name
guard let touch = touches.first, let attributeName = self.attributeName(at: touch.location(in: self)) else {
return
}
// Execute all handlers for that attribute, once:
tapHandlersByName[attributeName]?.forEach({ (handler) in
handler()
})
}
// MARK: - Internal Support
private func attributeName(at point: CGPoint) -> String? {
let location = CGPoint(
x: point.x - self.textContainerInset.left,
y: point.y - self.textContainerInset.top)
let characterIndex = self.layoutManager.characterIndex(
for: location,
in: self.textContainer,
fractionOfDistanceBetweenInsertionPoints: nil)
guard characterIndex < self.textStorage.length else {
return nil
}
let firstAttributeName = tapHandlersByName.allKeys.first { (attributeName) -> Bool in
if self.textStorage.attribute(NSAttributedStringKey(rawValue: attributeName), at: characterIndex, effectiveRange: nil) != nil {
return true
}
return false
}
return firstAttributeName
}
}
As ususal, I'll wait a couple of days before accepting my own answer, just in case something better shows up...

Keep all your views active (i.e. user interaction enabled).
Loop through the text view's gestures and disable the ones you do not need.
Loop through the table view's gestureRecognisers array, and make them depend on the text view's custom tap gesture using requireGestureRecognizerToFail.
If its a static table view, you can do this in view did load. For a dynamic table view, do this in 'willDisplayCell' for the text view cell.

Related

How to stop button action if user moves their finger off the button in sprite kit?

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
let touch = touches.first
let positionInScene = touch!.location(in: self)
let touchedNode = self.atPoint(positionInScene)
if let name = touchedNode.name {
if name == "leftbutton" {
print("left button stopped")
touchedNode.run(buttonStoppedPressAction)
player?.removeAllActions()
}
if name == "rightbutton" {
print("right button stopped")
touchedNode.run(buttonStoppedPressAction)
player?.removeAllActions()
}
}
}
Here I have code that when the user lifts off their finger from the buttons it stops the action but only if they lift of their finger inside the button. So if they press it and begin to move their finger somewhere else on the screen while continuously pressing down the button will not stop executing its code. Thank you for any help.
Essentially you should check for touch location at touch down and compare to the location at touch up. If the touch is no longer in the area of your button, you cancel all effects.
First, though, a point. It seems like you are handling button logic in the SKScene level, which is what tutorials often tell you to do. However, this may not be the best approach. The risks here, in addition to just a cluttered mess of a SKScene, emerge from handling multiple objects and how they react to touch events, and also additional complexity from multitouch (if allowed).
Years ago when I started with SpriteKit, I felt like this was a huge pain. So I made a button class that handles all the touch logic independently (and sends signals back to the parent when something needs to happen). Benefits: No needless clutter, no trouble distinguishing between objects, the ability to determine multitouch allowances per-node.
What I do in my class to see if the touch hasn't left the button before touch up is that I store the size of the button area (as a parameter of the object) and touch position within it. Simple simple.
In fact, it has baffled me forever that Apple didn't just provide a rudimentary SKButton class by default. Anyhow, I think you might want to think about it. At least for me it saves sooo much time every day. And I've shipped multiple successful apps with the same custom button class.
EDIT: Underneath is my barebones Button class.
import SpriteKit
class Button: SKNode {
private var background: SKSpriteNode?
private var icon: SKNode?
private var tapAction: () -> Void = {}
override init() {
super.init()
isUserInteractionEnabled = true
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
isUserInteractionEnabled = true
}
// MARK: Switches
public func switchButtonBackground(buttonBackgroundSize: CGSize, buttonBackgroundColor: SKColor) {
background = SKSpriteNode(color: buttonBackgroundColor, size: buttonBackgroundSize)
addChild(background!)
}
public func switchButtonIcon(_ buttonIcon: SKNode) {
if icon != nil {
icon = nil
}
icon = buttonIcon
addChild(icon!)
}
public func switchButtonTapAction(_ buttonTapAction: #escaping () -> Void) {
tapAction = buttonTapAction
}
// MARK: Touch events
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
tapAction()
}
}
And then you create the Button object by first initiating it, assigning it a background using a size and color, then assign it an icon, assign it a function to run when tapped and finally add it as a child to the scene.
let icon = SKNode()
let size = CGSize(width: 20.0, height: 20.0)
let button = Button()
button.switchButtonBackground(buttonBackgroundSize: size, buttonBackgroundColor: .clear)
button.switchButtonIcon(icon)
button.switchButtonTapAction(buttonPressed)
addChild(button)
The background defines the touch area for the button, and you can either have a color for it or determine it as .clear. The icon is sort of supposed to hold any text or images you want on top of the button. Just package them into an SKNode and you're good to go. If you want to run a function with a parameter as the tap action, you can just make a code block.
Hope that helps! Let me if you need any further help :).

iOS Swift 4 Screen game swipe boxes

I am creating an app so that user has to Swipe all the boxes from the screen. The goal is to swipe all the boxes until all boxes are swiped like example below.
So my question is:
Is it better to create the boxes using Stack View or rather draw manually by coordinates on the screen?
How to detect if user has swiped through the boxes (using UIGestureRecognizer)?
Note: When user swiped through the boxes, swiped boxes will turn into other color.
Both stack view or manually should work nicely. I would go with manually in this case but this is just a preference because you might have more power over it. But there is a downside that you need to reposition them when screen size changes. A third option is also a collection view.
The gesture recognizer should be pretty straight forward. You just add it on the superview of these cells and check the location when it moves or and when it starts. A pan gesture seems the most appropriate but it will not detect if user just taps the screen. This may be a feature but if you want to handle all touches you should either use a long press gesture with zero press duration (It makes little sense, I know but it works), or you may simply just override touch methods:
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first {
handleDrag(at: touch.location(in: viewWhereAllMiniViewsAre))
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first {
handleDrag(at: touch.location(in: viewWhereAllMiniViewsAre))
}
}
func handleDrag(at location: CGPoint) {
// TODO: handle the nodes
}
The gesture recognizer procedure would do something like:
func onDrag(_ sender: UIGestureRecognizer) {
switch sender.state {
case .began, .changed, .ended, .cancelled: handleDrag(at: sender.location(in: viewWhereAllMiniViewsAre))
case .possible, .failed: break
}
}
Now all you need is your data source. An array of all of your items should be enough. Like:
static let rows: Int = 10
static let columns: Int = 10
var nodes: [Node] = {
return Array<Node>(repeating: Node(), count: LoginViewController.rows * LoginViewController.columns)
}()
And a list of all of your mini views:
var nodeViews: [UIView] = { ... position them or get them from stack view or from collection view }
Now the implementation on touch handle:
func handleDrag(at location: CGPoint) {
nodeViews.enumerated().forEach { index, view in
if view.frame.contains(location) {
view.backgroundColor = UIColor.green
nodes[index].selected = true
}
}
}
This is just an example. An easy one and rather a bad one from maintenance perspective at least. In general I would rather have a node view of custom UIView subclass with a reference to a node. Also it should hook using delegate to a Node instance so that the node reports when the selection state changes.
This way you have much cleaner solution when handling touches:
func handleDrag(at location: CGPoint) {
nodeViews.first(where: { $0.frame.contains(location) }).node.selected = true
}
Checking if all are green is then just
var allGreen: Bool {
return !nodes.contains(where: { $0.selected == false })
}

iOS Button Visible, Not Clickable

I have a view in my storyboard that by default the alpha is set to 0. In certain cases the Swift file sets the alpha to 1. So either hidden or not. Before this view just contained 2 labels. I'm trying to add 2 buttons to the view.
For some reason the buttons aren't clickable at all. So when you tap it normally buttons change color slightly before you releasing, or while holding down on the button. But that behavior doesn't happen for some reason and the function connected to the button isn't being called at all.
It seems like an issue where something is overlapping or on top of the button. The button is totally visible and enabled and everything but not clickable. I tried Debug View Hierarchy but everything looks correct in that view.
Any ideas why this might be happening?
EDIT I tried making a class with the following code and in interface builder setting the container view to be that class.
class AnotherView: UIView {
override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
for view in self.subviews {
if view.isUserInteractionEnabled, view.point(inside: self.convert(point, to: view), with: event) {
return true
}
}
return false
}
}
Go with hitTest(_:with:) method. When we call super.hitTest(point, with: event), the super call returns nil, because user interaction is disabled. So, instead, we check if the touchPoint is on the UIButton, if it is, then we can return UIButton object. This sends message to the selector of the UIButton object.
class AnotherView: UIView {
#IBOutlet weak var button:UIButton!
override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
let view = super.hitTest(point, with: event)
if self.button.frame.contains(point) {
return button
}
return view
}
#IBAction func buttnTapped(sender:UIButton) {
}
}

Referencing the image being touched

In my viewDidLoad function I have a loop creating a 3x6 table of square images (blocks) . The idea is to move and match them eventually.
My question is, how do I assign the current image that is being touched or dragged, as a variable? Here's how I'm adding the image:
let squareImg = UIImageView(image:#imageLiteral(resourceName: "square"))
view.addSubview(squareImg)
And here is what I'm attempting to do:
#IBAction func handlePan(_ recognizer: UIPanGestureRecognizer) {
let translation = recognizer.translation(in: self.view)
if recognizer.state == UIGestureRecognizerState.began {
isDragging = true
let objectDragging = self.view //this is wrong and what I'm trying to correct
print("bg color of block being moved \(objectDragging?.backgroundColor)")
....
Store the images in an array, assign their index to the tag value, screw touchesBagan etc. and simply use gesture recognizers.
Adding images becomes:
var myImages = [UIImage]()
let squareImg = UIImageView(image:#imageLiteral(resourceName: "square"), tag: [//add a distinguished tag here])
view.addSubview(squareImg)
myImages.append(squareImg)
Now that your views are in an array (they don't need to be UIImageViews or even UIImages, just something unique), simply point to the correct thing in your array:
#IBAction func handlePan(_ recognizer: UIPanGestureRecognizer) {
let translation = recognizer.translation(in: self.view)
for view in self.subviews as [UIView] {
if let imageView = view as? UIImageView {
let image = myImages.tag
}
}
}
I'm aware this isn't exactly what you are asking for. But the technique is. I'll adjust my answer based on your feedback.
EDIT:
Based on the comments, it sounds like a good strategy going forward is to at least populate the tag property with "associated pairs in some kind of loop. Additionally, it sounds like some sort of build error is happening. Here's my take on that issue....
Tag properties are available to every object, be they a view or control. Also, they are of Int type. The last comment states the error references an incorrect argument in a function call, expecting an image. I think two separate things are going on.
(1) Populating the tag property for "associated" images in a loop.
If you are loading a "square" and a "circle" n number of times, instantiate things in a loop with an index and populate their tag property.
for index in 0...10 {
// instantiate your images
// associate these images by populating their tag values
imgSquare.tag = index
imgCircle.tag = index
// continue any other set here
}
Loop types in Swift are natively Int, so this is correct.
(2) The incorrect reference build error.
The build error is on line
let circleImg = UIImageView(image: circle, tag: [arrayCounter])
This is not a "canned" initializer for UIImageView, and from the build error it's not (yet) a coded extension to UIImageView. It sounds like there is a coded extension to UIImageView, one that expects two arguments, image and highlightedImage. If you want extend UIImageView for something like this, I'd create an extension with a convenience initializer:
extension UIImageView {
convenience init(image: UIImage, tag:Int) {
self.init()
self.image = image
self.tag = tag
}
}
This is a skeleton. You can add a guard statement and make it a bailable initializer. You can add frames, backgroundColor, whatever. The thing is - you currently do not have an initializer calling for 'image:tag:' but you are coding for one.
just try this
let objectDragging = recognizer.view
You could use the overrides provided by UIImageView.
For Example,
class DragImag: UIImageView {
var draggedView: UIView?
override init(frame: CGRect) {
super.init(frame: frame)
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?){
//here you get your desired view
draggedView = touches.view
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?){
}
}

Event on tapping out of a UITextView (i.e. UITextView losing focus)

I'd like to perform some processing on my UITextView once the user has finished editing it and tapped somewhere else on the screen. What's the best practice?
I almost managed to get the desired effect with func textViewDidEndEditing(textView: UITextView) however this only runs when the user has tapped 'Enter' key on the keyboard (which people very rarely do - they just commit the changes by tapping on somewhere else on the screen.)
The problem with func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) is that it doesn't care whether the UITextView was edited or not.
I think you can add an UITapGestureRecognizer on the view which hold the textView. In the UITapGestureRecognizer's selector, you can add the logic codes to handle the process. You can check the length of the textView's text to determine the UITextView was edited or not. Here is some sample code:
override func viewDidLoad() {
super.viewDidLoad()
let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(handleTap))
view.addGestureRecognizer(tapGestureRecognizer)
}
func handleTap() {
let text = textView.text
textView.resignFirstResponder() // loosing focus
if text.characters.count > 0 {
// textView edited
} else {
// textView not edited
}
}

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