I have an iOS application which runs a few different UIViewAnimation blocks to animate a few different objects on screen. This all works, but how can I stop ONE of the animation blocks WITHOUT stopping the rest?
I have tried using the following method:
[button.layer removeAllAnimations];
But it doesn't do anything, the animation just continues.
I then tried to use a simple BOOL value and get the animation to return from the method once the BOOL is set to "NO", but that doesn't work either.
Here is the animation which I am trying to stop:
-(void)undo_animation:(int)num {
// Fade out/in the number button label
// animation which lets the user know
// they can undo this particular action.
[UIView animateWithDuration:0.5 delay:0.2 options:(UIViewAnimationOptionRepeat | UIViewAnimationOptionCurveEaseIn | UIViewAnimationOptionAllowUserInteraction) animations:^{
// Mostly fade out the number button label.
((UIButton *)_buttons[num]).alpha = 0.2;
} completion:^(BOOL finished) {
[UIView animateWithDuration:0.5 delay:0.2 options:(UIViewAnimationOptionCurveEaseIn | UIViewAnimationOptionAllowUserInteraction) animations:^{
// Fade in the number button label.
((UIButton *)_buttons[num]).alpha = 1.0;
} completion:^(BOOL finished) {
// Stop the animation if the BOOL
// is set to 'NO' animations.
if (anim_state_button == NO) {
return;
}
}];
}];
}
Thanks, Dan.
You can't reach running animation property if you're using UIKit Animations. So I suggest to using Core Animation if you want to modify animation in the runtime of it.
And it's too simple to removing alpha of the view like below.
CABasicAnimation* fadein= [CABasicAnimation animationWithKeyPath:#"opacity"];
[fadein setToValue:[NSNumber numberWithFloat:1.0]];
[fadein setDuration:0.5];
[[moviepic layer]addAnimation:fadein forKey:#"MyAnimation"];
after adding animation to layer animation will start and than you can use delegate methods to be informed about animationDidFinish: method
- (void)animationDidStop:(CAAnimation *)theAnimation finished:(BOOL)flag
{
NSLog(#"Animation interrupted: %#", (!flag)?#"Yes" : #"No");
}
Also you can reach whenever you want from using;
[[moviepic layer] animationForKey:#"MyAnimation"];
And of course you need to add CoreAnimation Framework to your project.
Hope it helps.
I think the simple way is that remove all animations from your View Layer as all the animation are by default added into the View's Layer.
[yourRequiredView.layer removeAllAnimations];
My understanding is that removing all animations from the relevant layer should stop all animations. How about [((UIButton *)_buttons[num]).layer removeAllAnimations]; ?
I have a UIView called waves and it has a nice endless "floating" animation
[UIView animateWithDuration:1
delay:0
options:UIViewAnimationOptionAutoreverse | UIViewAnimationOptionRepeat | UIViewAnimationOptionCurveEaseInOut
animations:^{
CGPoint center = waves.center;
center.y += 5;
waves.center = center;
}
completion:nil];
Now if I add another animation, say moving this view to a different location, "floating" animations stops. It's a reasonable reaction and it's no problem to start the "floating" again in the completion block. I was just wondering if I'm missing something, perhaps in animation Options, to combine the two in a way that doesn't interrupt one another.
I was able to do so if the second animation is based on CGAffineTransfromScale, they combine no problem, but when I move the centre of the view it's not the case.
UPDATE: found a bug in performance. I have a button that calls the method responsible for moving the center of my View with animation. If I press it too fast before previous animation completed View just snaps into new position without animation and completion block is not called. Here's the code for that method:
- (void)wavesAnimationReversed:(BOOL)reversed {
CGFloat y = waves.frame.size.height*0.25;
y = reversed ? -y : y;
// CGFloat damping = reversed ? 1 : 0.65;
CGFloat damping = 1;
[UIView animateWithDuration:kWAVES_ANIMATION_DURATION
delay:0
usingSpringWithDamping:damping
initialSpringVelocity:0
options:UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionCurveEaseInOut
animations:^{
CGPoint center = waves.center;
center.y += y;
waves.center = center;
}
completion:^(BOOL finished) {
[self handleStartWavesFloating];
}];
}
If you want to perform multiple animations you should use animateKeyFrames.
That being said you can't animate something that is being animated (your description matches perfectly what will happen). That is, because the values from your view are already changed (it's real values), the animation happens out of your control.
Therefore, if you create a new animation, the default values are the end values of your first animation, when the 2nd animation triggers, it will automatically move the view to the new location to start the second animation.
I'm currently creating a loading bar that I would like to pause and reverse if a specific action is taken.
I have the following code below that animates one view in another. How would I go about pausing this animation and applying another animation on the CURRENT frame at that point in time for the animated object. I would like to be able to animate this bar down to the 0 width mark at any given time within the current animation.
-(void)animateProgressBar
{
CGRect endingFrame = self.frame;
[UIView animateKeyframesWithDuration:self.time delay:0.0 options:0 animations:^{
[UIView addKeyframeWithRelativeStartTime:0.0 relativeDuration:1.0 animations:^{
self.loadingBar.frame = endingFrame;
}];
} completion:^(BOOL finished) {
NSLog(#"TADA");
}];
}
If you want to start a new animation from where this one is now, just start the new animation using the the UIViewKeyframeAnimationOptionBeginFromCurrentState option (or if just doing animateWithDuration, use UIViewAnimationOptionBeginFromCurrentState).
You can import QuartzCore framework, add
#import <QuartzCore/QuartzCore.h>
And you can remove existing animation by calling:
[self.loadingBar.layer removeAllAnimations];
After that you can start new animation.
If you want to pause it you have to get reference to the current animation:
CALayer *currentLayer = self.loadingBar.layer.presentationLayer;
And you have to save it:
self.loadingBar.layer.transform = currentLayer.transform;
You can do it in another [UIView animateWith..... method.
I have animated a UIView so that it shrinks when the user touches a toggle button and it expands back to its original size when the user touches the button again. So far everything works just fine. The problem is that the animation takes some time - e.g. 3 seconds. During that time I still want the user to be able to interact with the interface. So when the user touches the button again while the animation is still in progress the animation is supposed to stop right where it is and reverse.
In the Apple Q&As I have found a way to pause all animations immediately:
https://developer.apple.com/library/ios/#qa/qa2009/qa1673.html
But I do not see a way to reverse the animation from here (and omit the rest of the initial animation). How do I accomplish this?
- (IBAction)toggleMeter:(id)sender {
if (self.myView.hidden) {
self.myView.hidden = NO;
[UIView animateWithDuration:3 animations:^{
self.myView.transform = expandMatrix;
} completion:nil];
} else {
[UIView animateWithDuration:3 animations:^{
self.myView.transform = shrinkMatrix;
} completion:^(BOOL finished) {
self.myView.hidden = YES;
}];
}
}
In addition to the below (in which we grab the current state from the presentation layer, stop the animation, reset the current state from the saved presentation layer, and initiate the new animation), there is a much easier solution.
If doing block-based animations, if you want to stop an animation and launch a new animation in iOS versions prior to 8.0, you can simply use the UIViewAnimationOptionBeginFromCurrentState option. (Effective in iOS 8, the default behavior is to not only start from the current state, but to do so in a manner that reflects both the current location as well as the current velocity, rendering it largely unnecessary to worry about this issue at all. See WWDC 2014 video Building Interruptible and Responsive Interactions for more information.)
[UIView animateWithDuration:3.0
delay:0.0
options:UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionAllowUserInteraction
animations:^{
// specify the new `frame`, `transform`, etc. here
}
completion:NULL];
You can achieve this by stopping the current animation and starting the new animation from where the current one left off. You can do this with Quartz 2D:
Add QuartzCore.framework to your project if you haven't already. (In contemporary versions of Xcode, it is often unnecessary to explicitly do this as it is automatically linked to the project.)
Import the necessary header if you haven't already (again, not needed in contemporary versions of Xcode):
#import <QuartzCore/QuartzCore.h>
Have your code stop the existing animation:
[self.subview.layer removeAllAnimations];
Get a reference to the current presentation layer (i.e. the state of the view as it is precisely at this moment):
CALayer *currentLayer = self.subview.layer.presentationLayer;
Reset the transform (or frame or whatever) according to the current value in the presentationLayer:
self.subview.layer.transform = currentLayer.transform;
Now animate from that transform (or frame or whatever) to the new value:
[UIView animateWithDuration:1.0
delay:0.0
options:UIViewAnimationOptionAllowUserInteraction
animations:^{
self.subview.layer.transform = newTransform;
}
completion:NULL];
Putting that all together, here is a routine that toggles my transform scale from 2.0x to identify and back:
- (IBAction)didTouchUpInsideAnimateButton:(id)sender
{
CALayer *currentLayer = self.subview.layer.presentationLayer;
[self.subview.layer removeAllAnimations];
self.subview.layer.transform = currentLayer.transform;
CATransform3D newTransform;
self.large = !self.large;
if (self.large)
newTransform = CATransform3DMakeScale(2.0, 2.0, 1.0);
else
newTransform = CATransform3DIdentity;
[UIView animateWithDuration:1.0
delay:0.0
options:UIViewAnimationOptionAllowUserInteraction
animations:^{
self.subview.layer.transform = newTransform;
}
completion:NULL];
}
Or if you wanted to toggle frame sizes from 100x100 to 200x200 and back:
- (IBAction)didTouchUpInsideAnimateButton:(id)sender
{
CALayer *currentLayer = self.subview.layer.presentationLayer;
[self.subview.layer removeAllAnimations];
CGRect newFrame = currentLayer.frame;
self.subview.frame = currentLayer.frame;
self.large = !self.large;
if (self.large)
newFrame.size = CGSizeMake(200.0, 200.0);
else
newFrame.size = CGSizeMake(100.0, 100.0);
[UIView animateWithDuration:1.0
delay:0.0
options:UIViewAnimationOptionAllowUserInteraction
animations:^{
self.subview.frame = newFrame;
}
completion:NULL];
}
By the way, while it generally doesn't really matter for really quick animations, for slow animations like yours, you might want to set the duration of the reversing animation to be the same as how far you've progressed in your current animation (e.g., if you're 0.5 seconds into a 3.0 second animation, when you reverse, you probably don't want to take 3.0 seconds to reverse that small portion of the animation that you have done so far, but rather just 0.5 seconds). Thus, that might look like:
- (IBAction)didTouchUpInsideAnimateButton:(id)sender
{
CFTimeInterval duration = kAnimationDuration; // default the duration to some constant
CFTimeInterval currentMediaTime = CACurrentMediaTime(); // get the current media time
static CFTimeInterval lastAnimationStart = 0.0; // media time of last animation (zero the first time)
// if we previously animated, then calculate how far along in the previous animation we were
// and we'll use that for the duration of the reversing animation; if larger than
// kAnimationDuration that means the prior animation was done, so we'll just use
// kAnimationDuration for the length of this animation
if (lastAnimationStart)
duration = MIN(kAnimationDuration, (currentMediaTime - lastAnimationStart));
// save our media time for future reference (i.e. future invocations of this routine)
lastAnimationStart = currentMediaTime;
// if you want the animations to stay relative the same speed if reversing an ongoing
// reversal, you can backdate the lastAnimationStart to what the lastAnimationStart
// would have been if it was a full animation; if you don't do this, if you repeatedly
// reverse a reversal that is still in progress, they'll incrementally speed up.
if (duration < kAnimationDuration)
lastAnimationStart -= (kAnimationDuration - duration);
// grab the state of the layer as it is right now
CALayer *currentLayer = self.subview.layer.presentationLayer;
// cancel any animations in progress
[self.subview.layer removeAllAnimations];
// set the transform to be as it is now, possibly in the middle of an animation
self.subview.layer.transform = currentLayer.transform;
// toggle our flag as to whether we're looking at large view or not
self.large = !self.large;
// set the transform based upon the state of the `large` boolean
CATransform3D newTransform;
if (self.large)
newTransform = CATransform3DMakeScale(2.0, 2.0, 1.0);
else
newTransform = CATransform3DIdentity;
// now animate to our new setting
[UIView animateWithDuration:duration
delay:0.0
options:UIViewAnimationOptionAllowUserInteraction
animations:^{
self.subview.layer.transform = newTransform;
}
completion:NULL];
}
There is a common trick you can use to do this, but it is necessary to write a separate method to shrink (and another similar one to expand):
- (void) shrink {
[UIView animateWithDuration:0.3
animations:^{
self.myView.transform = shrinkALittleBitMatrix;
}
completion:^(BOOL finished){
if (continueShrinking && size>0) {
size=size-1;
[self shrink];
}
}];
}
So now, the trick is to break the 3 seconds animation of shrinking into 10 animations (or more than 10, of course) of 0.3 sec each in which you shrink 1/10th of the whole animation: shrinkALittleBitMatrix. After each animation is finished you call the same method only when the bool ivar continueShrinking is true and when the int ivar size is positive (the view in full size would be size=10 and the view with minimum size would be size=0). When you press the button you change the ivar continueShrinking to FALSE, and then call expand. This will stop the animation in less than 0.3 seconds.
Well, you have to fill the details but I hope it helps.
First: how to remove or cancel a animation with view?
[view.layer removeAllAnimations]
if the view have many animations, such as, one animation is move from top to bottom, other is move from left to right;
you can cancel or remove a special animation like this:
[view.layer removeAnimationForKey:#"someKey"];
// the key is you assign when you create a animation
CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:#"someKey"];
when you do that, animation will stop, it will invoke it's delegate:
- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag
if flag == 1, indicate animation is completed.
if flag == 0, indicate animation is not completed, it maybe cancelled、removed.
Second: so , you can do what you want to do in this delegate method.
if you want get the view's frame when the remove code excute, you can do this:
currentFrame = view.layer.presentationlayer.frame;
Note:
when you get the current frame and remove animation , the view will also animate a period time, so currentFrame is not the last frame in the device screen.
I cann't resolve this question at now. if some day I can, I will update this question.
I subclasses UIButton to create my own UIRoundButton. I'm trying to animate a custom property called radius. It does change, but it does immediately. I tried to increase the animation duration until 5000 but the animation is still happening in a millisecond.
Here is the code:
UIRoundButton *tempItem = [self.buttons objectAtIndex:currentElement];
[tempItem setInnerColor:UIColorFromRGB(0xcdcdcd)];
currentElement = currentElement + 1;
UIRoundButton *tempItem2 = [self.buttons objectAtIndex:currentElement];
[tempItem2 setInnerColor:UIColorFromRGB(0xff0000)];
[UIView beginAnimations:#"ToggleViews" context:nil];
[UIView setAnimationDuration:5000];
tempItem.radius = 20;
tempItem2.radius = 40;
[UIView commitAnimations];
Any idea?
Implicit view animations don't work on custom properties. You have to do this at the CALayer level if you want this kind of behavior.