I'm trying to pick up a bit of Swift lang and I'm wondering how to convert the following Objective-C into Swift:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesBegan:touches withEvent:event];
UITouch *touch = [touches anyObject];
if ([touch.view isKindOfClass: UIPickerView.class]) {
//your touch was in a uipickerview ... do whatever you have to do
}
}
More specifically I need to know how to use isKindOfClass in the new syntax.
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
???
if ??? {
// your touch was in a uipickerview ...
}
}
The proper Swift operator is is:
if touch.view is UIPickerView {
// touch.view is of type UIPickerView
}
Of course, if you also need to assign the view to a new constant, then the if let ... as? ... syntax is your boy, as Kevin mentioned. But if you don't need the value and only need to check the type, then you should use the is operator.
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
super.touchesBegan(touches, withEvent: event)
let touch : UITouch = touches.anyObject() as UITouch
if touch.view.isKindOfClass(UIPickerView)
{
}
}
Edit
As pointed out in #Kevin's answer, the correct way would be to use optional type cast operator as?. You can read more about it on the section Optional Chaining sub section Downcasting.
Edit 2
As pointed on the other answer by user #KPM, using the is operator is the right way to do it.
You can combine the check and cast into one statement:
let touch = object.anyObject() as UITouch
if let picker = touch.view as? UIPickerView {
...
}
Then you can use picker within the if block.
I would use:
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
super.touchesBegan(touches, withEvent: event)
let touch : UITouch = touches.anyObject() as UITouch
if let touchView = touch.view as? UIPickerView
{
}
}
Another approach using the new Swift 2 syntax is to use guard and nest it all in one conditional.
guard let touch = object.AnyObject() as? UITouch, let picker = touch.view as? UIPickerView else {
return //Do Nothing
}
//Do something with picker
Related
I'm implementing a passThroughView by creating a transparent View on top and override hitTest().
passThroughView should consume touches from Apple Pencil and if touch type is not from pencil, it pass touches to the view underneath.
The problems are:
parameter "event" in hitTest contains no touch, so I can't check touch type in hitTest
I can get touch from touchesBegan and check touch type, but it get called only after hitTest returned true
I subclass UIWindow and override sendEvent() but this function also called after hitTest (and I don't know why)
class WindowAbleToKnowTouchTypes: UIWindow {
override func sendEvent(_ event: UIEvent) {
if event.type == .touches {
// This get called after Hittest
if event.allTouches!.first!.type == .pencil {
print("This touch is from Apple Pencil")
}
}
super.sendEvent(event)
}
}
Is there anyway to check touchType to decide to pass or consume touches?
I ended up using a different approach, it could be useful for many cases: If I can't get touchType in hitTest(), I can still get the touchType with GestureRecognize:
class CustomGestureRecognizer : ImmediatePanGesture {
var beganTouch : UITouch!
var movedTouch : UITouch!
var endedTouch : UITouch!
override func shouldReceive(_ event: UIEvent) -> Bool {
// You can check for touchType here and decide if this gesture should receice the touch or not
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
// Save touch for later use
if let firstTouch = touches.first {
beganTouch = firstTouch
}
super.touchesBegan(touches, with: event)
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
// Save touch for later use
if let touch = touches.first {
movedTouch = touch
}
super.touchesMoved(touches, with: event)
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent) {
// Save touch for later use
if let touch = touches.first {
endedTouch = touch
}
super.touchesEnded(touches, with: event)
}
}
In the target function of the gestureRecognizer, you can get the UITouch by:
let beganTouch = customGesture.beganTouch
let touchType = beganTouch.touchType
I'm making a SpriteKit game in XCode using swift. I want to make custom buttons in the menu, and I'm following this tutorial to do it. Everything's working fine except the touchesMoved function.
override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {
var touch: UITouch = touches.allObjects[0] as UITouch
var location: CGPoint = touch.locationInNode(self)
if defaultButton.containsPoint(location) {
activeButton.hidden = false
defaultButton.hidden = true
} else {
activeButton.hidden = true
defaultButton.hidden = false
}
}
Apparently, the "touches.allObjects[0] as UITouch" doesn't work anymore in Swift 2. I've searched for alternatives, but I haven't found any that works. How could I replace that line of code?
For some reason the tutorial is using NSSet rather than Set<UITouch> in touchesMoved. I wonder if they translated the tutorial from Objective-C to Swift, and missed updating them?
func touchesMoved(_ touches: Set<UITouch>,
withEvent event: UIEvent?)
touchesMoved - Apple docs
Notice the touches argument is of type NSSet in your code, and the Apple docs have it as Set<UITouch>.
Once you switch to Set<UITouch>, try using touches.first as! UITouch
Be careful if it can be nil, I'm not familiar with the user input functions on iOS.
If you allow multitouch later you'll need to check the entire Set, rather than just grabbing the first (and only) UITouch element.
The correct way to do it is this:
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
for touch: AnyObject in touches {
let location = touch.locationInNode(self)
if defaultButton.containsPoint(location) {
activeButton.hidden = false
defaultButton.hidden = true
} else {
activeButton.hidden = true
defaultButton.hidden = false
}
}
}
I want to scroll a node in sprite kit without uiscrollview
// In touchesMoved
let touch: UITouch = touches.first as! UITouch;
let location:CGPoint = touch.locationInNode(self);
let lastPosition = touch.previousLocationInNode(self)
var newLoc = selectNode.position.y + (location.y - lastPosition.y)
// Check if the top part is reached
if(newLoc < selectNodeStart){
newLoc = selectNodeStart
}
if(selectNode.position.y >= selectNodeStart){
// let sk = SKAction.moveToY(newLoc, duration: 0.1)
// selectNode.runAction(sk)
selectNode.position.y = newLoc
}
If I use the sk action the result is very horrible, but without the result is also horrible
An Elegant way of doing this in SpriteKit is using a UIPanGestureRecognizer to detect the touch, and inside of that you will create a sequence of SKActions that will accelerate or decelerate the movement. You might have to use the update method and/or touches to handle the pan stopping or another immediately starting. Unfortunately, if you want to use only SpriteKit you will have to use SKActions to implement this.
I thought I'd also mention an easier (and possible better looking) way to do this. Take a look at "ScrollKit", which works pretty well (although it does use a UIScrollView): https://github.com/bobmoff/ScrollKit
If you found that the UIScrollView doesn't pass touches up to touchesMoved, you could try a few different things.
- You can add a UITapGestureRecognizer and set on the UIScrollView CanCancelContentTouches to YES.
- You can subclass UIScrollView and override the touchesMethods so that if the user isn't scrolling, touch information will be passed up the responder chain:
override func touchesBegan(touches: NSSet, withEvent event: UIEvent){
if (!self.dragging){
self.nextResponder.touchesBegan(touches , withEvent: event)
}
else{
super.touchesBegan(touches , withEvent: event)
}
}
override func touchesMoved(touches: NSSet, withEvent event: UIEvent){
if (!self.dragging){
self.nextResponder.touchesMoved(touches , withEvent:event)
}
else{
super.touchesMoved(touches , withEvent: event)
}
}
override func touchesEnded(touches: NSSet, withEvent: event UIEvent){
if (!self.dragging){
self.nextResponder.touchesEnded(touches , withEvent: event)
}
else{
super.touchesEnded(touches , withEvent: event)
}
}
I have a simple piece of code in which i have overridden touchesBegan,Ended,Cancelled(empty block) and touchesMoved.
If i click ( i'm testing on Desktop PC ) with the mouse touchesBegan it's called, but touchesEnded is called only when i move finger for a while. That makes impossible to recognize a single tap or a drag of the finger, and handle them differently.
I don't understand if this is an emulator problem or i am misunderstanding the whole process. Did you have the same problem?
I have a simple solution for my application, like check a "first move" variable in touchesBegan, but this is a pure technical question.
Thank you in advance.
This is all i use, apart from drawRect that it's not important.
I guess it's not a problem in my code.
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
let touch = touches.allObjects[0] as UITouch
let touchPoint = touch.locationInView(self)
println("touchesBegan")
if (Draw!){
path.moveToPoint(touchPoint)
path.addLineToPoint(touchPoint)
self.setNeedsDisplay()
}
}
override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {
let touch = touches.allObjects[0] as UITouch
let touchPoint = touch.locationInView(self)
println("touchesMoved")
if (Draw!){
path.addLineToPoint(touchPoint)
self.setNeedsDisplay()
}
}
override func touchesEnded(touches: NSSet, withEvent event: UIEvent) {
let touch = touches.allObjects[0] as UITouch
let touchPoint = touch.locationInView(self)
println("touchesEnded")
if (Draw!){
path.addLineToPoint(touchPoint
path = UIBezierPath() // Create new path for next line
self.setNeedsDisplay()
}
}
I am quite sure this is an emulator problem.
Please see the code below. It works like a charm at my end.
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
didMove = false;
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
didMove = true;
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
if (didMove == true)
{
//finger was moved
NSLog(#"finger was moved");
}
else
{
//it's a tap
NSLog(#"finger not moved it's a tap");
}
}
While we are at it, can I bring your attention to UIGestureRecognizers? Try to use them since they make life a breeze.
I am having trouble creating a function "touchesBegan" and then creating a UIPoint and UITouch constant or variable that holds an x and y coordinate. I have the exact code I want in Objective-C but I do not know what it's equivalent is in Swift. Here is the Objective-C code which I want to basically translate into Swift code...
NOTE: This is a Single View Application, NOT a game... Thanks in advance.
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [touches anyObject];
CGPoint point = [touch locationInView:self.view];
if (point.x < 160) {
var = 10;
}
else{
var = 20;
}
}
As of Swift 1.2, use this
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent)
{
var touch = touches.first as! UITouch
var point = touch.locationInView(self)
if point.x < 160 {
var = 10;
}
else{
var = 20;
}
}
Where's the problem?
var touch = touches.anyObject() as! UITouch
var point = touch.locationInView(self.view)
if point.x < 160 {
var variableName = 10;
}
else{
var variableName = 20;
}
Swift 1.2 changed the syntax for touchesBegan. See the UIResponder Reference.
func touchesBegan(_ touches: Set<NSObject>, withEvent event: UIEvent)
And don't forget to reference the super.
super.touchesBegan(touches, withEvent: event)
Here is an edited example of implementing this code from techotopia.com which might give you more information on the other three touches functions.
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
var touch = touches.anyObject() as! UITouch
var point = touch.locationInView(self.view)
// Insert if statements
super.touchesBegan(touches, withEvent: event)
}