Flutter: Activate multiple gesture detectors after long press - dart

I have an application where there is multiple cards in a grid that each have their own gesture detector. I want to be able to long press on one of the cards and then drag over the other cards and activate each cards gesture detector separately. I am not sure if this is possible.

It might be too late, but use onLongPressMoveUpdate(updates) and check localOffsetFromOrigin.dx or localOffsetFromOrigin.dy for positive and negative values for left,right,up,down drag respectively.

GestureDetector has an event onPanStart which might be what you are looking for. Listen to this event on the other Cards after the LongPress event is activated.
onPanStart
A pointer has contacted the screen and has begun to move.
or else there is another widget to look into, the swipedetector, here

Related

ios voiceover slider double tap and hold, but for custom view

I've created a custom view that acts like a UISlider - there is a "track", and a handle to "grab" to change the value. For particular reasons, I can't just make it a subclass of UISlider. I'm trying to make this slider as accessible as possible with VoiceOver. I have accessibilityIncrease and accessibilityDecrease on my custom view that handle single finger drag up and single finger drag down. This changes the value of the slider by 10% at a time.
However, I'd like to allow more fine grained control, just like a non-VoiceOver slider. By default , UISlider has double tap and hold, and you can drag up/down to "pan" the slider. I'd like to add exactly that to my custom view, but I can't find the correct incantation to handle the double tap and hold gesture.
Is there something I can do to mimic the double tap and hold gesture from UISlider on my custom view?
Thanks very much!!!
If you want to implement this kind of new gesture for VoiceOver users, just forget it.
The recommended gesture for this kind of UI control is definitely the implementation of adjustable value as you already did apparently.
I don't think it's a good idea to try and implement new VoiceOver gestures in an application because its users have their habits and they may be totally lost with your customed control if they cannot handle it unless you add an hint to explain but that's definitely not what I recommend anyway.
Otherwise, you could take a look at the pass through concept introduced in the What's New in Accessibility WWDC 2017 video that deals with the same idea but for a panning gesture...

Is it possible to attach a gesture recognizer to a button, so that the user swipes up after/during the button press?

I read through a few similar questions here, but most of them are for much older versions of Swift.
This tutorial shows how to create a gesture recognizer and works pretty well: https://www.ioscreator.com/tutorials/swipe-gesture-ios-tutorial-ios11
What I'd like to accomplish is to add functionality that would allow the user to swipe up or down after pressing a button, while still holding the button, and have my app react to the combination of the specific button being pressed and the upward or downward swipe gesture.
Here's the specific design I'm trying to implement. Basically I'd like the user to press the "A" button and then swipe up or down to get the "#" or "b".
Is this possible? The # & b could be image views or buttons (though if they're buttons, I don't want them to be pressable on their own). If this is a crazy design, I welcome suggestions for improvement.
You want to use a UILongPressGestureRecognizer (probably in conjunction with image views). It has the advantage that first it recognizes a finger held down in one spot (the "A") and then it tracks the movement of that finger (panning up to the sharp or down to the flat). Where the finger is held down — i.e., is it in the "A" or not — will determine whether to recognize in the first place. Then if you do recognize, you watch where the finger goes and decide whether it has entered the sharp or the flat.
I ended up using a Pan Gesture Recognizer, and it worked out really well! I am simply using the y coordinate of the pan gesture to determine if the user is moving his/her finger up to the sharp or down to the flat.

Custom UIGestureRecognizer conflicting with UITapGestureRecognizer

So I have this project that I took from somebody else and they have implemented this OneFingerRotationGestureRecognizer (https://github.com/melle/OneFingerRotationGestureDemo/blob/master/OneFingerRotationGestureDemo/OneFingerRotationGestureRecognizer.m) for a circular slider. Additionally, they have added a UITapGestureRecognizer on top of that, so you could tap a value within that circular slider and the value would jump to that specific one. Now the problem is, when I drag that thing just a very small amount (imagine putting your thumb onto the control and tilting left/right), then the UITapGestureRecognizer also fires! And this is a problem, because I want to be able to grab the circular slider wherever I want (there is no handle or something). And when I only drag it a little, then the value just jumps to that spot where I did that small dragging. Somehow I need to cancel that tap gesture as soon as that OneFingerRotationGestureRecognizer started registering touches. I tried what is described here: https://developer.apple.com/documentation/uikit/touches_presses_and_gestures/coordinating_multiple_gesture_recognizers/preferring_one_gesture_over_another?language=objc but didn't have any success with that :-(.
What can I do? I'm afraid the solution is so simple that I just don't see it.

How would you make a horizontal picker view in sprite kit to choose different characters?

I am trying to make a game in SWIFT (SpriteKit) where the user can pick between a large amount of characters to play as during the game. The 'characters' would be in what looks like a horizontal picker view. It is similar to the app "Ball King's" player chooser that looks like this:
and
I do not know where to start and any help would be great! Thank you!
Just set up a UISwipeGestureRecognizer in your view. When a swipe is detected, get the direction of the swipe and either display the next or previous sprite with an animation. If you haven't used gesture recognizers documentation is here. Another option is to simply detect swipes generically using touchesBegan, touchesMoved, etc.

Slide Effect for iOS

I'm new to developing iOS apps,
I've successfully implemented a Swipe Gesture Recognizer,
What I was wondering is if there is an easy to use recognizer like the swipe gesture. That would let you implement the homescreen page turning effect but just on a small view in the view controller?
If your unclear on what effect I mean, when you look at the iPhone's homescreen you can drag your finger and it responds instantly (unlike swipe) and also has some spring feeling to it, is this some effect I can use, or do I manually have to program this into the code if so is there a tutorial that explains this?
Thanks,
I hope my question makes sense.
Have a look at UIPanGestureRecognizer:
https://developer.apple.com/library/ios/documentation/uikit/reference/UIPanGestureRecognizer_Class/Reference/Reference.html
UIPanGestureRecognizer is a concrete subclass of UIGestureRecognizer
that looks for panning (dragging) gestures. The user must be pressing
one or more fingers on a view while they pan it. Clients implementing
the action method for this gesture recognizer can ask it for the
current translation and velocity of the gesture.
A panning gesture is continuous. It begins
(UIGestureRecognizerStateBegan) when the minimum number of fingers
allowed (minimumNumberOfTouches) has moved enough to be considered a
pan. It changes (UIGestureRecognizerStateChanged) when a finger moves
while at least the minimum number of fingers are pressed down. It ends
(UIGestureRecognizerStateEnded) when all fingers are lifted.
Clients of this class can, in their action methods, query the
UIPanGestureRecognizer object for the current translation of the
gesture (translationInView:) and the velocity of the translation
(velocityInView:). They can specify the view whose coordinate system
should be used for the translation and velocity values. Clients may
also reset the translation to a desired value.
Edit: The spring feeling part you would need to implement yourself. Since iOS 7 there is UIDynamics which contains different animators, for what you describe you may need UIGravityBehavior and maybe UICollisionBehaviour. Look at the WWDC 2013 videos for this topic, I think you will find some examples there.

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