My ImageView rotates but while it rotates it doesn't recognize touches on itself.
Do you think it's okay if I create a button via code that's over the ImageView that recognizes the touch?
When an animation is applied on any UIView or any subclass object of a UIView like UIImageView, UIButton etc then it does not detect touch events because when an animation is applied to a view, the animated property changes to its end value right away. what you are actually seeing on screen is the presentation layer of your views layer.
To answer your question, Yes, you can make a UIButton that covers up the area of the UIImageView to detect touch events on it. That sounds like the easiest to implement option in this case.
Apart from that, this link may also help you in the process. Hit testing animating layers
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I have what should be a very simple thing to do. I'm working on someone else's code, and I want to enlarge a UIButton because it's too small for users. I made it bigger in the storyboard, but when I run the app, the associated IBAction only gets hit when touching where the original rectangle was before I changed it. The button is still visibly larger, but only a portion of it receives touch events. Does anyone know what else might be at play here?
Note: there are no views on top of the new area that the button occupies, so I don't think the touches get picked up by a view on top.
Something to check is whether the UIButton has an ancestor view (i.e. a view in its superview chain) that is the smaller size. Hit-tests only pass down the view hierarchy if the touch is contained within the view so a smaller superview will stop the touches outside its bounds, even if the touch is inside the button.
Is the IBAction hooked up to "touch up inside" in Interface Builder/Storyboard? I've made mistakes where I hook it up with a different kind of event, which exhibits behaviours like you're experiencing.
Found the issue. There was a view being programmatically added on top of the button. It's origin.x was being hardcoded to where the buttons width use to end.
Here's the scenario I am trying to implement:
I already have a view that can let user draw doodles by touching inside the view directly (like a doodle canvas). This view implements touchesBegan, touchMoved, and touchEnded handlers to draw lines from touch event parameters.
Now instead of that, I want user to be able to drag and move another UIView on this canvas view and can still draw lines just like they touch directly. For example, user can drag a pen image view on the canvas view to draw pen-style lines.
In this case, how can I transfer the movement of this pen image view to the canvas so it recognize it? One more question: if I want this canvas view to only recognize movements of drag other views rather than touching directly, what I should do?
(Sorry that this question is little too general, just want to get some pointer of it)... Thanks!
A better way to look at the problem is
How can I transfer movement on the canvas into the location of a pen
image view?
That's easy. You already have all the code that keeps track of movement in the canvas (touchesBegan, touchesMoved, touchesEnded), so all you need to do is change to center property of the pen view to track the movement in the canvas. (Obviously, you'll need to apply small X and Y offsets to put the center of the pen view at the correct location).
The only non-obvious detail that you need to be aware of is that the pen view must have userInteractionEnabled set to NO. That way, the pen view won't interfere with touches reaching the canvas view.
Note that UIImageView has user interaction disabled by default, so you don't need to do anything if the pen view is a UIImageView. However, if you're using a generic UIView to display the pen, then you need to disable user interaction in storyboard under the Attributes inspector or disable it in code, e.g. in viewDidLoad.
I am building a word tetris kind of an app. Now I have to move a Uiview containing 8 uibuttons towards the bottom of the screen based on time and also track the position of uibuttons as the user taps specified button.
Am I suppose to use Block based animation or core animation to do the task.
Currently if I am animating frame and center of superview it seems like I have to do the same for the subviews as well inside the block.
Any input would be handy.
You can use UIView block animation to animate a view and it's subviews quite simply.
However, neither UIView animation nor core animation will let the user click on buttons as they are animating. Button actions don't work at all on "in flight" animations. There's no automatic way to do that. (At least none that I know of.)
Instead, you have to add a tap gesture recognizer to the parent view, and do hit testing on the presentation layer of your parent view to see which sublayer of the presentation layer is tapped.
I have to add a button. This should be glowing non stop. So I used an external library. By this I have to add the image to an UIImageView and then the imageview to the view. This is added to the button. The glow is enabled by the startGlow: method which takes in a UIView. This forces me to add the UIView to the UIButton. The problem comes in when I touch the button, it is not responsive inside which is filled with UIView. The edges seems to work fine. Any fix for this? I want the button to be responsive for all the TouchInside event. Thank you
If you don't need to interact with a view you can turn off the interaction by setting the userInteractionEnabled property to NO. You should then be able to interact with the view or UIButton below it.
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!