I want to make my UIView swipeable by X-axis and by Y-axis separately. For example if user swipes view vertically it triggers one action and if user swipes view horizontally it triggers another action. I don't know how to implement this correctly so I'm thinking of attaching two UIPanGestureRecognizers to my view. Is it wrong?
Just use a single UIPanGestureRecognizer and use its translation(in: UIView?) and velocity(in: UIView?) functions to determine which direction the user is swiping.
Don't use two Gesture use only single UIPanGestureRecognizer and call this method with your panGesture:
-(void)moveVerticallyAndHorizentally:(UIPanGestureRecognizer *)gesture{
CGPoint velocity = [gesture velocityInView:self.view]; // you can use your own view
if (fabs(velocity.y) > fabs(velocity.x)) {
// vertical motion
}
else if (fabs(velocity.x) > fabs(velocity.y)){
// Horizental motion
}
}
Hope this will help you.
Related
The Problem
I have a UIScrollView containing a UIView that I wish to allow the user to pan using a UIPanGestureRecognizer.
In order for this to work as desired, users should be able to pan the view with one finger, but also be able to pan the scroll view with another finger - doing both at the same time (using one finger for each).
However, the scroll view ceases to work when the user is panning a view contained within it. It cannot be panned until the view's pan gesture ends.
Attempted Workaround
I tried to work around this by enabling simultaneous scrolling of both the pan view and the UIScrollView that contains it by overriding the following UIGestureRecognizerDelegate method:
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
However, this makes it so that panning the view also moves the scroll view. Each element's panning gesture should be independent of the other, not linked.
Demo Project
I have created a simple demo project that should demonstrate this, here:
https://github.com/jeffc-dev/ScrollViewPannerTest
This project contains a scroll view with a square view that should be able to be panned independently of its containing scroll view, but can not.
Why I'm Doing This
The point of this is to make it easier/quicker for a user to find a destination to pan the view to. The is somewhat analogous to rearranging icons in Springboard: You can use one finger to pan an app icon while simultaneously panning between pages with another finger, quickly finding a place to drop it. I'm not using a paged scroll view - just a normal one - and I want it to be a seamless panning gesture (I don't need/want the user to have to enter a 'wiggle mode') but the basic principle is the same.
UPDATE: DonMag helpfully came up with the idea of using a UILongPressGestureRecognizer to move the view out of the scroll view for panning, which does seem promising. However, if I went that route I think I'd need to seamlessly transition to using a UIPanGestureRecognizer after doing so (as I do use some pan gesture recognizer-specific functionality).
I'm sure there are different ways to do this, but here is one approach...
Instead of using a UIPanGesture I used a UILongPressGesture.
When the gesture begins, we move the view from the scrollView to its superview. While we continue to press the view and drag it around, it is now independent of the scrollView. When we end the gesture (lift the finger), we add the view back to the scrollView.
While dragging, we can use a second finger to scroll the content of the scroll view.
The main portion of the code looks like this:
#objc func handleLongPress(_ g: UILongPressGestureRecognizer) -> Void {
switch g.state {
case .began:
// get our superview and its superview
guard let sv = superview as? UIScrollView,
let ssv = sv.superview
else {
return
}
theScrollView = sv
theRootView = ssv
// convert center coords
let cvtCenter = theScrollView.convert(self.center, to: theRootView)
self.center = cvtCenter
curCenter = self.center
// add self to ssv (removes self from sv)
ssv.addSubview(self)
// start wiggling anim
startAnim()
// inform the controller
startCallback?(self)
case .changed:
guard let thisView = g.view else {
return
}
// get the gesture point
let point = g.location(in: thisView.superview)
// Calculate new center position
var newCenter = thisView.center;
newCenter.x += point.x - curCenter.x;
newCenter.y += point.y - curCenter.y;
// Update view center
thisView.center = newCenter
curCenter = newCenter
// inform the controller
movedCallback?(self)
default:
// stop wiggle anim
stopAnim()
// convert center to scroll view (original superview) coords
let cvtCenter = theRootView.convert(curCenter, to: theScrollView)
// update center
self.center = cvtCenter
// add self back to scroll view
theScrollView.addSubview(self)
// inform the controller
endedCallback?(self)
}
}
I forked your GitHub repo and added a new controller to demonstrate: https://github.com/DonMag/ScrollViewPannerTest
You'll see that it is just a Starting Point for this approach. The view being dragged (actually, in this demo, you can use two fingers to drag two views at the same time) uses closures to inform the controller about the dragging...
Currently, "drag/drop" does not affect any other subviews in the scrollView. The only closure that does anything is the "ended" closure, at which point the controller re-calcs the scrollView's contentSize. The "moved" closure could be used to re-position views -- but that's another task.
I have a UIView that contains many UIView subviews. When the user tries to pan gesture one of the subviews, I want them to be able to drag it anywhere else on the screen.
However, I can only drag these smaller views within the bigger UIView they are contained in. When the user first tries to pan gesture the smaller view, is there any way to programmatically create a second UIView on top and then drag around the second UIView instead? The second UIView would be completely new from the smaller view that was first touched.
This is the handler function I have so far, just for reference. I don't know where I would programmatically create the second UIView, though. Any help would be greatly appreciated:
#objc func handlePanGesture(sender: UIPanGestureRecognizer) {
// get translation
var translation = sender.translation(in: view)
sender.setTranslation(CGPoint.zero, in: view)
// drag around current UIView
var newView = sender.view as! UIView
newView.center = CGPoint(x: newView.center.x+translation.x, y: newView.center.y+translation.y)
newView.isMultipleTouchEnabled = true
newView.isUserInteractionEnabled = true
if sender.state == UIGestureRecognizer.State.began {
// add something you want to happen when the Label Panning has started
}
if sender.state == UIGestureRecognizer.State.ended {
// add something you want to happen when the Label Panning has ended
}
if sender.state == UIGestureRecognizer.State.changed {
// add something you want to happen when the Label Panning has been change ( during the moving/panning )
} else {
// or something when it's not moving
}
}
Is there any way to be able to drag the smaller views anywhere while maintaining the same layout I have right now
Because of the way touch works, it is impossible by default for a view to be touched when it reaches the boundaries of its superview. But you can overcome that limitation by overriding hitTest in the superview.
A very common pattern that enables dragging of views outside of their superview, is to create a snapshot or clone of the original view as soon as the gesture begins, you can of course hide the original view so to the user it feels like the same UI element is being dragged. It's a pattern used by Apple in their drag and drop sample code here
https://developer.apple.com/documentation/uikit/drag_and_drop/adopting_drag_and_drop_in_a_custom_view
Have a look at line 36 in ViewController+Drag.swift for the relevant code.
I use a ImageScrollView from here, which is basically a UIScrollView to allow pinch to zoom into a picture. I now wanted to add the possibility to swipe down the picture to dismiss the view controller. I created a UIPanGestureRecognizer and it works fine if zoom scale is at the minimum value (so the whole picture is visible without zoom). But how can I skip the pan gesture recognizer if the zoom scale is above the minimum value? Because it lays on top of the ImageScrollView, I can't scroll in the picture because scrolling gesture is fetched by the UIPanGestureRecognizer. Any idea how to solve this?
For show image like whatsApp imageView functionality you go with the apple framework QuikLook. It will automatically handle Zoom, Dismiss the image while Swipe etc.
It also support for the documents. It will reduce your effort a lot
It's too easy to handle this operation by adding a trigger on swipe action (gesture calling method).
When zoomScale > minimumValue; set returnstatement
A simple example with Swift 4:
let zoomScale: 1.0
let minimumValue: 0.5
func handlePanGesture(gesture: UIPanGestureRecognizer) {
if (#<set pan gesture down moving condition>#) {
if (zoomScale > minumumValue) {
return
}
}
// perform your next operations
}
I have a view in an iOS application (Obj-C) which has an image view in the centre, and immediately below that a slider.
The image view shows album artwork, and the slider can be used to adjust the now-playing track position.
There is also a pair of left and right Swipe Gesture Recognizers. These are used to skip to the next or previous tracks.
The problem is that the swipe gesture recognizers seem to over-ride the users moving the slider thumb.
In my gesture recognizer code I check that the point touched was inside the image view, but it still stops the slider from being moved. (The thumb moves, but jumps back to it's original position when you remove your finger).
This is the code I use to reject the gesture if it's not inside the image view.
- (IBAction)swipeLeftGestureAction:(UISwipeGestureRecognizer *)sender {
// Get the location of the gesture.
CGPoint tapPoint = [sender locationInView:_artworkImageView];
// Make sure tap was INSIDE the artwork image frame.
if( (tapPoint.x <0)
|| (tapPoint.y < 0 )
|| (tapPoint.x > _artworkImageView.frame.size.width)
|| (tapPoint.y>_artworkImageView.frame.size.height))
{
NSLog(#"Outside!");
return;
}
NSLog(#"Swipe LEFT");
[_mediaController skipNext];
}
So my question is, how do I limit the gesture to work ONLY when swiped across the image view?
Try to put the code that restricts the gesture's area in gestureRecognizer:shouldReceiveTouch: and return NO in case you don't want the gesture to receive this touch. It should prevent the gesture from over taking the slider interaction.
If you're only interested in swipes that are inside the image view, then you should add the swipe gesture recognizer to the image view instead of adding it to your entire view. Then you won't need any special logic.
There is a dedicated method for checking if a point is inside a view
BOOL isPointInsideView = [_artworkImageViewpointInside:tapPoint withEvent:nil];
But I think what is happening is that if you will look at the tapPoint is that it actually outside of your imageView
And if your slider is really close to the imageView so the slider captures the movement, what you should do is check on the slider if it is intended for the slider and propagate on to the imageView if needed
Or inherit the UISlider and reduce its response rect
I'm designing a game that takes place on a grid. The grid needs to respond to pan gestures that begin in one square and end in another. I have a custom view controller class called GameVC which contains the grid of UIViews of subclass GameGridSquare. I want the game to perform an action when, for example, a pan gesture begins and ends in neighboring squares. I have a storyboard wired with properties that name each square by row and column: self.A1, self.A2, ... self.H7, self.H8. As a pan gesture is recognized, I want the GameVC to receive the two GameGridSquares where UIGestureRecognizerStateBegan and UIGestureRecognizerStateEnded so it can determine the appropriate action, like so:
-(void)validatePanGestureFrom:(GameGridSquare*)beginSquare
to:(GameGridSquare*)endSquare
What's the best way to do this? My recognizers are functional and returning coordinates, but I think I need to explore hit-testing.
If I add recognizers to the individual GameGridSquares, I get undesired results. For example, a pan that begins in A1 and ends in B2 would be recognized by A1 alone. This suggests that I need a pan recognizer on GameVC that can detect when the gesture begins and ends in separate subviews.
From what I've read, I believe that the UIGestureRecognizerDelegate protocol may be helpful here. I also understand that a custom UIPanGestureRecognizer subclass would allow me to override hitTest:withEvent but I'm not sure where to even begin with that. Any ideas about how I should approach this?
This was what I was after:
Find which child view was tapped when using UITapGestureRecognizer
UIView* view = gestureRecognizer.view;
CGPoint loc = [gestureRecognizer locationInView:view];
UIView* subview = [view hitTest:loc withEvent:nil];