I have a project where I’m adding three UILabels to the view controller’s view. When the user begins moving their finger around the screen, I want to be able to determine when they their finger is moving over any of these UILabels.
I’m assuming a UIPanGestureRecognizer is what I need (for when the user is moving their finger around the screen) but I’m not sure where to add the gesture. (I can add a tap gesture to a UILabel, but this isn’t what I need)
Assuming I add the UIPanGestureRecognizer to the main view, how would I go about accomplishing this?
if gesture.state == .changed {
// if finger moving over UILabelA…
// …do this
// else if finger moving over UILabelB…
// …do something else
}
You can do this with either a UIPanGestureRecognizer or by implementing touchesMoved(...) - which to use depends on what else you might be doing.
For pan gesture, add the recognizer to the view (NOT to the labels):
#objc func handlePan(_ g: UIPanGestureRecognizer) {
if g.state == .changed {
// get the location of the gesture
let loc = g.location(in: view)
// loop through each label to see if its frame contains the gesture point
theLabels.forEach { v in
if v.frame.contains(loc) {
print("Pan Gesture - we're panning over label:", v.text)
}
}
}
}
For using touches, no need to add a gesture recognizer:
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
if let t = touches.first {
// get the location of the touch
let loc = t.location(in: view)
// loop through each label to see if its frame contains the touch point
theLabels.forEach { v in
if v.frame.contains(loc) {
print("Touch - we're dragging the touch over label:", v.text)
}
}
}
}
Related
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 })
}
I am currently working on an arcade app where the user taps for the sprite to jump over an obstacle and swipes down for it to slide under an obstacle. My problem is that when I begin a swipe the touchesBegan function is called so the sprite jumps instead of sliding. Is there a way to distinguish these two?
You can use a gestures state to fine tune user interaction. Gestures are coordinated, so shouldn't interfere with each other.
func handlePanFrom(recognizer: UIPanGestureRecognizer) {
if recognizer.state != .changed {
return
}
// Handle pan here
}
func handleTapFrom(recognizer: UITapGestureRecognizer) {
if recognizer.state != .ended {
return
}
// Handle tap here
}
How about using a slight delay for your touch controls? I have a game where I do something similar using a SKAction with delay. Optionally you can set a location property to give your self a bit of wiggle room with the touchesMoved method incase someone has a twitchy finger (thanks KnightOfDragon)
let jumpDelayKey = "JumpDelayKey"
var startingTouchLocation: CGPoint?
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in touches {
let location = touch.location(in: self)
// starting touch location
startingTouchLocation = location
// start jump delay
let action1 = SKAction.wait(forDuration: 0.05)
let action2 = SKAction.run(jump)
let sequence = SKAction.sequence([action1, action2])
run(sequence, withKey: jumpDelayKey)
}
}
func jump() {
// your jumping code
}
Just make sure the delay is not too long so that your controls dont feel unresponsive. Play around with the value for your desired result.
Than in your touches moved method you remove the SKAction if your move threshold has been reached
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in touches {
let location = touch.location(in: self)
guard let startingTouchLocation = startingTouchLocation else { return }
// adjust this value of how much you want to move before continuing
let adjuster: CGFloat = 30
guard location.y < (startingTouchLocation.y - adjuster) ||
location.y > (startingTouchLocation.y + adjuster) ||
location.x < (startingTouchLocation.x - adjuster) ||
location.x > (startingTouchLocation.x + adjuster) else {
return }
// Remove jump action
removeAction(forKey: jumpDelayKey)
// your sliding code
}
}
You could play around with Gesture recognisers although I am not sure that will work and how it affects the responder chain.
Hope this helps
I'm building a game that is primarily played by tapping the screen (anywhere). I have currently added a settings button that when tapped, opens up a settings window.
Problem is, when the settings button is tapped, interaction happens in the game too. Is there any way to prevent this from happening?
My settings screen works in conjunction with a settings function and the override touches began function through a boolean expression.
The game is played through a UITapGestureRecognizer that was added to the view in didMoveToView.
/* Game Interaction & Playability */
override func didMoveToView(view: SKView) {
let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: Selector("tapped:"))
view.addGestureRecognizer(tap)
}
/* Settings Button Interaction */
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
for touch in touches {
let positionInScene = touch.locationInNode(self)
let touchedNode = self.nodeAtPoint(positionInScene)
if let name = touchedNode.name {
if name == "Settings" {
if settingsOpen == false {
settings()
} else {
settings()
}
}
}
}
}
Well, you've got a couple gesture recognizers working here. You don't actually need to add a recognizer to the view to know if someone is tapping it. That's handled already for you (hence the reason why touchesBegan works without adding another recognizer).
I would say remove that extra recognizer, and move the code for tapped: to your touchesBegan.
I am working with xcode to create a view that allows users to drag buttons. with the code below, I can move the button to the touch and drag from there, but I cant click the button and drag.
override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
for obj in touches {
let touch = obj as! UITouch
let location = touch.locationInView(self.view)
word1Button.center = location
}
}
Buttons respond to touch events, so when the user touches down within the bounds of a button the view underneath will not receive those touch events. You can get around this by using a gesture recogniser on your button instead of relying on the lower level touch delivery methods. A long press gesture recognizer would probably work best:
// Where you create your button:
let longPress = UILongPressGestureRecognizer(target: self, action: "handleLongPress:")
word1Button.addGestureRecognizer(longPress)
//...
func handleLongPress(longPress: UILongPressGestureRecognizer) {
switch longPress.state {
case .Changed:
let point = longPress.locationInView(view)
button.center = point
default:
break
}
}
Note that by default, the UILongPressGestureRecognizer needs the user to hold down for 0.5 seconds before the gesture starts recognizing (and therefore starts dragging). You can change this with the minimumPressDuration property of UILongPressGestureRecognizer. Be careful not to make it too short though - as soon as the gesture recognizes it will cancel other touches to the button, preventing the button action from being fired when the touch is lifted.
I am creating a game, similar to Flappy Bird but the user holds their finger on the screen and dodges the obstacles, rather than tapping to make the bird fly.
I am doing this by having a UIScrollView, in which UIView's are used as obstacles. When the user touches a UIView, the game is over.
How do I detect the users touch of a UIView from within a UIScrollView? I am using Swift with Xcode Beta 4.
EDIT: This is screenshot of the game
As you can see, the user moves their finger between the grey blocks (UIViews) as they scroll up.
By setting userInteractionEnabled to NO for your scroll view, the view controller will start receiving touch events since UIViewController is a subclass of UIResponder. You can override one or more of these methods in your view controller to respond to these touches:
touchesBegan: withEvent:
touchesMoved: withEvent:
touchesEnded: withEvent:
touchesCancelled: withEvent:
I created some example code to demonstrate how you could do this:
class ViewController: UIViewController {
#IBOutlet weak var scrollView: UIScrollView!
// This array keeps track of all obstacle views
var obstacleViews : [UIView] = []
override func viewDidLoad() {
super.viewDidLoad()
// Create an obstacle view and add it to the scroll view for testing purposes
let obstacleView = UIView(frame: CGRectMake(100,100,100,100))
obstacleView.backgroundColor = UIColor.redColor()
scrollView.addSubview(obstacleView)
// Add the obstacle view to the array
obstacleViews += obstacleView
}
override func touchesBegan(touches: NSSet!, withEvent event: UIEvent!) {
testTouches(touches)
}
override func touchesMoved(touches: NSSet!, withEvent event: UIEvent!) {
testTouches(touches)
}
func testTouches(touches: NSSet!) {
// Get the first touch and its location in this view controller's view coordinate system
let touch = touches.allObjects[0] as UITouch
let touchLocation = touch.locationInView(self.view)
for obstacleView in obstacleViews {
// Convert the location of the obstacle view to this view controller's view coordinate system
let obstacleViewFrame = self.view.convertRect(obstacleView.frame, fromView: obstacleView.superview)
// Check if the touch is inside the obstacle view
if CGRectContainsPoint(obstacleViewFrame, touchLocation) {
println("Game over!")
}
}
}
}
You can programmatically add a gesture recognizer as follows
var touch = UITapGestureRecognizer(target:self, action:"action")
scrollView.addGestureRecognizer(touch)
However, this gesture recognizer won't work for you. UITapGestureRecognizer will only return for a tap, not a tap and hold, and UILongPressGestureRecognizer doesn't give information about location, so you want to use a UIPanGestureRecognizer. It continually tells you how far the touch has moved.
var touch = UIPanGestureRecognizer(target:self, action:"handlePan")
scrollView.addGestureRecognizer(touch)
#IBAction func handlePan(recognizer:UIPanGestureRecognizer) {
let translation = recognizer.translationInView(self.view)
recognizer.setTranslation(CGPointZero, inView: self.view)
}
You can use the constant "translation" to move your object, it represents the distance the person has slid their finger. Use that plus the location of your bird to move the bird to a new point. You have to reset the translation to zero after this function is called.
Edit: With the format of your game, this code should be the best method.
So, all together, the code to find the location of your finger should be as follows.
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
for touch: AnyObject in touches {
let location = touch.locationInView(yourScrollView)
}
}
#IBAction func handlePan(recognizer:UIPanGestureRecognizer) {
let translation = recognizer.translationInView(self.view)
var currentLocation : CGPoint = CGPointMake(location.x+translation.x, location.y+translation.y)
recognizer.setTranslation(CGPointZero, inView: self.view)
}
currentLocation is a CGPoint containing the location of the current touch, wherever the finger is slid to. As I do not know how you are creating the views to be avoided, you will have to use the y coordinate of currentLocation to determine the x boundaries of the views that are to be avoided at that y, and use < or > comparators to determine if the x boundary of the touch is inside either of those views.
Note: you have to declare location so it can be accessed in handlePan
var location : CGPoint = CGPointZero