Is it possible in some way to receive and respond to touch events from a UIView that is not visible. I tried -- as well as read from the Apple docs -- that simply setting 'hidden' will not work. I'm looking for an alternative to achieve the same effect.
A hidden view disappears from its window and does not receive input events. It remains in its superview’s list of subviews, however, and participates in autoresizing as usual. Hiding a view with subviews has the effect of hiding those subviews and any view descendants they might have. This effect is implicit and does not alter the hidden state of the receiver’s descendants.
if a view has set userInteractionEnabled to YES it will be touchable when hidden. Try to experiment with UIButton for example.
Make it transparent, not hidden (with alpha set to 0). If that doesn't work, make it nearly transparent (alpha set to 0.1).
Related
I have two UIStackViews and they animate so when it is supposed to be tapped the overlapping shouldn't exist or be a problem anymore, but it still is.
Is there a way to still accept touches on a control that's covered by another control?
This is how it looks without running it...when it loads..the square stackview in the middle stays put and the other one which is still behind it...grows adn the buttosn aren't covered anymore
You can set userInteractionEnabled to false on the covering views
Or if you want both to receive events, set exclusiveTouch to false, and userInteractionEnabled to true.
I'm trying to make my first game using SpriteKit + Swift.
The problem I'm trying to solve right now is that if I add to my main SKView a SUBVIEW without any buttons just with a background color and size and touch it, my main view handles this touch like there is no subview at all.
So the subView of type UIView like doesn't exist for UITapGestureRecognizer of parent view. And the only way I found to solve it, is to put a subView-sized button on the subview without text and handler. But this way looks creepy...
It could be that your subView (or one of its parents views) has the userInteractionEnabled set to false. UIView has the userInteractionEnabled set to true by default, but for example UIImageView (which is a subclass of UIView) has the userInteractionEnabled set to false by default.
When set to NO, user events—such as touch and keyboard—intended for
the view are ignored and removed from the event queue. When set to
YES, events are delivered to the view normally. The default value of
this property is YES.
(...)
Note
Some UIKit subclasses override this property and return a different
default value. See the documentation for that class to determine if it
returns a different value.
See Apple docs for more info.
It could be not your subView by itself, but one of its parents views too, because this setting is propagated down.
If set to NO, this view (along with its subviews) is excluded from
receiving touches. Touches on this view or one of its subviews "fall
through" to a view behind it.
source: Programming iOS by Matt Neuburg
For more, check On iOS, if a superview's userInteractionEnabled is NO, then all subviews are disabled as well?
I was wondering how to make a popup window similar to this example:
The origin window is full of buttons that when is selected will then pull up the image I desire to use.
I would simply create a reusable UIView component and everything you need as a subview, such as a UIImageView for your image, a UILabel or a UIButton in the top right. Here is the process to show it:
Create a UIView that takes up the full screen, make it black, and maybe 0.5 alpha.
Create another UIView which is your primary pop-up view, make it slightly smaller than the previous view, but make sure both of these views are subviews of the parent subview.
Add the desired elements on to the pop-up view as subviews, I would even suggest creating a UIView subclass if you plan to use this a lot.
To present the pop-up, make sure both views are set to hidden = true when created and so that when a button is selected, you can set them to hidden = false
If you would like them to be animated, simply start them off with alpha = 0.0 and use something like UIView's animateWithDuration and set the pop-up view to alpha = 1.0
There is a lot of little details you can change to cater to your needs, but this is the basic structure on how to accomplish your goal.
Check out UIView animation methods here.
EDIT: The crux of this problem is that scroll indicators do not show during programmatic scrolling, but I would like them to. My original question (provided below) assumed this had something to do with userInteractionEnabled, but it does not. The mention of a master and slave UIScrollView is also possibly distracting from my core problem (the need to show scroll indicators during a programmatic scroll). Apologies to those of you who answered or commented based on my misleading assumptions/info.
Possible Solution: The only way I found to do this was to use the fact that scroll indicators are instances of UIImageView and use a category on it to hack the alpha. This article shows the approach. It was then a case of using tags and scroll view delegate methods to turn the alpha permanently on prior to a programmatic scroll, and permanently off when the scroll is finished. This feels hacky though, so any further suggestions would be welcome!
Everything below this line is the original unedited question to provide context to users' answers and comments
Setting userInteractionEnabled in a UIScrollView object to NO appears to disable the scroll indicators upon programmatic scrolling. This happens even if you have self.showsVerticalScrollIndicator = self.showsHorizontalScrollIndicator = YES;
Is there any way to programmatically scroll the scroll view but still show the indicators?
(To provide some context: I have a slave scrollview that mimics a master scrollview by hooking up the scrollview delegate callbacks and passing the content offset to the slave scrollview. However, I don't want the user to be able to directly manipulate the slave scrollview, but I do want scroll indicators).
Instead of setting userInteractionEnabled to false try setting the UIScrollView's scrollEnabled property to false. The doc. says "When scrolling is disabled, the scroll view does not accept touch events" that should mean that you should still be able to programmatically scroll the UIScrollView. Hope this helps - Did not test it out let me know.
You could try putting a transparent UIView (alpha == 0.0) over your scroll view (but as a sibling in the view hierarchy, not as a subview). Set touchesEnabled to YES on the transparent view, and it will intercept touches heading for the scroll view.
I have two views that flip based on a button press within the view. The view has two CAGradientLayers as sublayers. If I flip immediately after the action method fires, the button is in the process of changing the opacity of the gradients and so you see stuttering (the UIVIew flip animation is having to accommodate the button that is itself changing.)
I can hack a solution by doing a performWithSelection:withObject:afterDelay:0.1f, but it feels like such a hack. I tried setting the layer's needsDisplay property and testing for when it was clears, but probably this is insufficient to tell me the screen itself has redrawn.
Dav
In the end this has no solution. I have since found that when animating a view there are severe performance implication if you also try to animate the super views. You can see this in many iOS apps where the app animates an image in a scrolling list - the scrolling stumbles.
So what I learned is either animate something, or it's view, but not both!