I have made a CAAnimation (CAAnimationGroup to be precise) that scale and fade (opacity) from 0 -> 1 and then back 0 -> 1. The animation also repeats forever
since I have set animationGroup.repeatCount = .greatestFiniteMagnitude. This animation is applied to a UILabel and makes the label appear and disappear with a nice animation over and over.
I now want to change the text between each repetition of the animation (after it disappears but before it appears again). What is the correct way of doing this?
I managed to get this working by removing the animationGroup.repeatCount = .greatestFiniteMagnitude line and manually restarting the animation in the animation delegate method animationDidStop(_:finished:). I also change the text of the label in the delegate method before restarting the animation. I'm not sure if this is the best solution though.
Related
I have checked all over for a solution to one problem:
I have set an imageView to move with a timer, but I have another timer counting seconds, and every time the second-timer goes off, the imageView spawns in it's original position.
Here is the post where I found my solution:
Swift: timer resetting the view
Here it suggests that I use "imageView.translatesAutoresizingMaskIntoConstraints = true", which actually works fine. But I have one problem. If I can't use Auto Layout, how do I tell the imageView where to spawn when the timer hasn't begun?
Because "imageView.translatesAutoresizingMaskIntoConstraints = true" basically kills my Auto Layouts, so it spawns about 30-40 pixels away from the middle, which it is set to do.
I don't find any use in showing my code, since it has got to do with the "imageView.translatesAutoresizingMaskIntoConstraints = true" command.
So I'm making a simple trivia game and I have a timerView that shrinks as time passes. When the user selects an answer, it needs to stop shrinking immediately - it must be very responsive. I give the user 10 seconds per question. Originally I would animate 10 times (with a duration of 1.0f), calling the next "segment" of animation in the completion block of the previous animation. In the completion block I would check to see if the user has tapped an answer, and if so I don't continue the chain. That solution works fine except that it's not very responsive because it's on a per second basis-- user taps an answer at the start of the second segment and the bar has a noticeable continuation.
My solution to THAT problem was to instead have 1000 animation calls with a duration of 0.01f. After doing that, the responsiveness was on point - the view stops animating as soon as I tap an answer -- the issue though, is that it's not actually 10 seconds, it takes more like 20.
So question number 1: what's the smallest time interval animateWithDuration can actually process properly?
Question number 2: is there a better way to accomplish what I'm trying to do accomplish?
ill answer question two: yes there definitely is a better way, have a look at CADisplayLink
use it to shrink your view a little bit each frame, and end the display link when you need to
the most responsive way is: the user taps an answer, you response in the touch callback, remove animations. you can remove animations by CALayer's removeAllAnimations method
Another way to do it is to set the view to shrinking using a single animation with linear timing, and then set the speed of the view's layer to 0 to pause the animation. When you set the speed on the layer to 0 the animation pauses instantly.
This works because under the covers, UIView animation actually creates and installs CAAnimation objects on the view's layers. It's possible to pause and continue an in-flight UIView animation just like you can a CAAnimation.
I have a project called KeyframeViewAnimations (link) on github that allows you to pause, continue, or "scrub" UIView and CAAnimations back and forth with a slider. You could use that technique. The tricky bit will be figuring out how far along the animation is.
Update
The animation is working for setEnabled=NO.
The animation for setEnabled=YES is being triggered when UIScrollView is scrolling, the UIButton is inside the scrollview and the animation for setEnabled=NO is being triggered when UIScrollView is done scrolling.
So, I think the reason why animation for setEnabled=YES is not working is because the view is moving. I am not sure but this seems to be the only logical explanation from what I have found so far. I did a test with dispatch_after() and the animation worked for setEnabled too, in other words the animation is working if it is being triggered when the view is not moving.
What I need to do ?
I have two different background images for UIButton one for UIControlStateNormal and another for UIControlStateDisabled.
I want a effect where UIButton slowly transitions over from one state to another
What have I been doing ?
BOOL enableDisable = YES;
[UIView transitionWithView:((UIButton*)object)
duration:3.3
options:UIViewAnimationOptionTransitionCrossDissolve
animations:^{ [((UIButton*)object) setEnabled:enableDisable]; }
completion:nil];
The Problem
UIButton transforms to setEnabled=NO state over the duration but no matter what I put in the options setEnabled happens almost instantly.
is there something I am missing ?
Thanks in advance for your time and response.
Unfortunately, enable or disabled state for UIView aren't part of animatable properties in apple docs. The animatable properties are:
frame, center, bounds, transform, alpha, backgroundColor, contentStretch
Reference here: UIView animation
However if you want to create custom property for animation, you can have a look at this post which describes a way to achieve it. Create a custom animatable property
I can confirm that your code works as expected both for the transition
enabled: NO -> YES
and for the transition
enabled: YES -> NO
So, my guess is that something else is happening in your app that somehow interferes with the transition. Try defining a completion block like:
...
completion:^(BOOL finished) {
NSLog(#"FINISHED? %#", finished?#"YES":#"NO");
} ];
and add a trace log before the transitionWith call or inside the animation block to check how long the transition runs from start to completion.
My guess is that while the button is transitioning something else is happening that changes its state and as a secondary effect breaks the transition. I fear that without seeing more code, it will not be possible to help you further...
I'm trying to implement transition used in settings menu in Facebook's Paper app: http://blog.brianlovin.com/design-details-paper-by-facebook/#1. I'm using my custom UIViewControllerAnimatedTransitioning object, but I can't achieve the same effect, no matter what type of animation I'm using. So I have some questions:
1) Which animation is used? It looks like cells start to move really fast, and then halt to their final position. Looks like I need POPDecayAnimation, but the result isn't even close.
2) Is delay between animations achieved with setting animation's beginTime depending on cell's index? Or first cells have bigger velocity than last cells?
As Injectios suggested AMWaveTransition is kinda close to Paper's animation. I ended up using it with some adjustments.
I also asked this question on pop github page, you can view it here. Their answer might be useful if you want to implement this animation yourself:
Hey! I implemented that in Paper. The animations on each cell are POPSpringAnimations, and they're connected together by (every frame) updating the toValue of each animation to point to the current value of the one before. Hope that helps!
In cellForRowAtIndexPath, use UIViewAnimation block.
Set cell properties as per your requirement:
indentationLevel
indentationWidth
shouldIndentWhileEditing
Then in animation block, change frame position.
For example for first cell, indetationLevel = 1, and indentationWidth = cell.frame.size.width, then update it to indetationLevel = 0 and indentationWidth = 0 in that animation block. And for the further cells you can multiply this values by (cellIndexPath+1)
For more details visit : https://developer.apple.com/library/ios/Documentation/UIKit/Reference/UITableViewCell_Class/index.htm
P.S.: Update the logic as per your requirement
I'm developing an iOS application and I have a simple question.
If you start an animation for an image (like rotating it) for an unlimited time, and then after a few seconds set the alpha to zero to hide it [[self image]setAlpha:0];. Is the animation still working in the background or not? Do you always have to set [layer removeAllAnimations];? I'm asking this because I don't wan't to slow down the cpu.
Thanks!
You really want to use removeAllAnimations, not just setting the alpha to zero. If you use a timer or display link to monitor the presentationLayer (which indicates the current properties of the view) of the animated object, you'll see that the animation is still in progress, even if the alpha is zero.