Custom iOS 7 Interactive Pop Animation goes blank after animating - ios

I am recreating the UINavigationController Push animation using the new iOS 7 custom transitioning APIs.
I got the view pushing and popping fine using animationControllerForOperation
I added a edge gesture recogniser for the interactive pop gesture.
I used a UIPercentDrivenInteractiveTransition subclass and integrated code from WWDC 2013 218 - Custom Transitions Using View Controllers
It looks like it removes the fromViewController by mistake, but I don't know why.
The steps are:
Interactive pop starts
Finger is lifted after a short distance - red screenshot
The view animates back a short distance.
Red view is removed (I think) - black screenshot.
The full code is on GitHub, but here are 2 parts which I guess are important.
Gesture delegate
- (void)didSwipeBack:(UIScreenEdgePanGestureRecognizer *)edgePanGestureRecognizer {
if (state == UIGestureRecognizerStateBegan) {
self.isInteractive = YES;
[self.parentNavigationController popViewControllerAnimated:YES];
}
if (!self.isInteractive) return;
switch (state)
{
case UIGestureRecognizerStateChanged: {
// Calculate percentage ...
[self updateInteractiveTransition:percentagePanned];
break;
}
case UIGestureRecognizerStateCancelled:
case UIGestureRecognizerStateEnded: {
if (state != UIGestureRecognizerStateCancelled &&
isPannedMoreThanHalfWay) {
[self finishInteractiveTransition];
} else {
[self cancelInteractiveTransition];
}
self.isInteractive = NO;
break;
}
}
}
UIViewControllerAnimatedTransitioning protocol
- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext
{
// Grab views ...
[[transitionContext containerView] addSubview:toViewController.view];
// Calculate initial and final frames
toViewController.view.frame = initalToViewControllerFrame;
fromViewController.view.frame = initialFromViewControllerFrame;
[UIView animateWithDuration:RSTransitionVendorAnimationDuration delay:0.0 options:UIViewAnimationOptionCurveLinear animations:^{
toViewController.view.frame = finalToViewControllerFrame;
fromViewController.view.frame = finalFromViewControllerFrame;
} completion:^(BOOL finished) {
[transitionContext completeTransition:YES];
}];
}
Anyone know why the screen is blank? Or Can anyone point me to some sample code. Apple don't appear have any sample code for interactive transitions using the percent driven interactions.

The first issue was a bug in the Apple sample code that I copied. The completeTransition method should have a more intelligent BOOL parameter like this:
[UIView animateWithDuration:RSTransitionVendorAnimationDuration delay:0.0 options:UIViewAnimationOptionCurveLinear animations:^{
toViewController.view.frame = finalToViewControllerFrame;
fromViewController.view.frame = finalFromViewControllerFrame;
} completion:^(BOOL finished) {
[transitionContext completeTransition:![transitionContext transitionWasCancelled]];
}];
Thanks to #rounak for pointing me to the objc.io post.
This then presented another issue relating to the animation. The animation would stop, present a blank view and them carry on. This was almost defiantly a UIKit bug. The fix was to set the completionSpeed to 0.99 instead of 1.0. The default value is 1.0 so I guess that setting it to this doesn't do some side effect in their custom setter.
// self is a UIPercentDrivenInteractiveTransition
self.completionSpeed = 0.99;

I don't think you need a UIPercentDrivenInteractiveTransition subclass. I just create a new UIPercentDrivenInteractiveTransition object, hold a strong reference to it and return it in interactionControllerForAnimationController method.
This link for interactive transitions is quite helpful.

Related

Why are completion handlers of [UIView animate] called in a wrong order?

In my project there's a ViewController which contains a few subviews(e.g. buttons).
It shows/hides those buttons, always with animation.
It has an interface like this:
#interface MyViewController: UIViewController
- (void)setMyButtonsVisible:(BOOL)visible;
#end
And an implementation looks like this:
- (void)setMyButtonsVisible:(BOOL)visible
{
if( visible )
{
// "show"
_btn1.hidden = NO;
_btn2.hidden = NO;
[UIView animateWithDuration:0.2 animations:^{
_btn1.alpha = 1.0;
_btn2.alpha = 1.0;
}];
}
else
{
// "hide"
[UIView animateWithDuration:0.2 animations:^{
_btn1.alpha = 0.0;
_btn2.alpha = 0.0;
} completion:^(BOOL finished) {
_btn1.hidden = YES;
_btn2.hidden = YES;
}];
}
}
When [_myVC setMyButtonsVisible:NO] is called, and then after some time ( > 0.2s) [_myVC setMyButtonsVisible:YES] is called, everything is OK.
However, it setMyButtonsVisible:YES is called immediately after ( < 0.2s) setMyButtonsVisible:NO, the animations overlap and setMyButtonsVisible:NO callback is called the last.
I've tried to change "hide" duration to 0.1, it doesn't help - after "hide(0.1)"+"show(0.2)" calls, "hide" callback is called after the "show" callback and my buttons are not visible.
I've added a quick-fix by caching the visible param and checking in "hide" completion handler if the state should be !visible.
My questions are:
Why the first animation completion handler is called the last if animations overlap?
What are better approahes to discard a previous "overlapping" animation?
Check the finished flag on completion:
if (finished) {
_btn1.hidden = YES;
_btn2.hidden = YES;
}

Coordinating two UIView animations on UIButton down/up

I'm trying to build an animation around a UIButton. The UIButton has a UIImageView that contains an image that I'd like to shrink when the UIButton is held down and then when the UIButton is let go, I'd like to play a separate animation that does a bounce.
The issue I'm experiencing right now is that the 2nd part of the animation doesn't seem to play if I press down and then up very quickly. If I press and hold (wait for the first animation to finish), then let go, it seems to work fine.
Here's the relevant code:
-(void)pressedDown
{
[UIView animateWithDuration:0.2 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{
self.heartPart.layer.transform = CATransform3DMakeScale(0.8, 0.8, 1);
} completion:nil];
}
-(void)pressedUp
{
[UIView animateWithDuration:0.8
delay:0.0
usingSpringWithDamping:20
initialSpringVelocity:200
options:UIViewAnimationOptionBeginFromCurrentState
animations:^{
self.heartPart.layer.transform = CATransform3DIdentity;
}
completion:nil];
}];
}
In my ViewDidLoad I add the following:
[self.heartButton addTarget:self
action:#selector(pressedUp)
forControlEvents:UIControlEventTouchUpInside];
[self.heartButton addTarget:self
action:#selector(PressedDown)
forControlEvents:UIControlEventTouchDown];
Any idea how I can get the two animations to sequence and not interrupt each other even on a quick press?
Here's a potential plan of action. Keep two global variables, BOOL buttonPressed and NSDate *buttonPressDate. When the button is pressed, you should set buttonPressed to true and set buttonPressDate to the current date. Now in the touch up method, you would set buttonPressed to false and check whether the time interval between buttonPressDate and the current date is greater than the duration of the animation. If it is, then run the touch up animation; if not, return. In the completion block of the touch down method, you would check if the button was still pressed. If it is, then do nothing; if it's not pressed anymore, then run the touch up animation.
The effect you'll get using this approach should be the following: if you tap the button quickly, it will run the full 0.2-second shrink animation and then run the enlarge animation in sequence.
Now, if you don't want the touch down animation to run in the case of a quick touch, you should probably delay the first animation and check if the button is still pressed when you start it. If it was a quick touch, you would run a modified animation that covered both the touch down and touch up phases.
You could try out the following :-
//Set only one target with TouchUpInside.
[self.heartButton addTarget:self
action:#selector(pressedUp)
forControlEvents:UIControlEventTouchUpInside];
-(void)pressedDown
{
[UIView animateWithDuration:0.2 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{
self.heartPart.layer.transform = CATransform3DMakeScale(0.8, 0.8, 1);
}
completion:
[self pressedUp];
//Or
[self performSelector:#selector(pressedUp) withObject:self afterDelay:0.5];
];
}
-(void)pressedUp
{
[UIView animateWithDuration:0.8
delay:0.0
usingSpringWithDamping:20
initialSpringVelocity:200
options:UIViewAnimationOptionBeginFromCurrentState
animations:^{
self.heartPart.layer.transform = CATransform3DIdentity;
}
completion:nil];
}];
}
This way as first animation is completed then next animation will start But my concern is that it won't look appropriate and it would be a bit long animation to show to a user. Rest it's upto your app design and what all it is going to achieve with it.
I assume you are familiar with the concept of operations. If not then NSOperations allow you to keep your code modular and enable you to set the order of execution.
You could create a custom subclass of NSOperation and run animation within its execution block, then add operations with animations on queue each time user interacts with the button.
Apart from documentation from Apple, there is a great example of how to subclass NSOperation available on Github:
https://github.com/robertmryan/AFHTTPSessionOperation/blob/master/Source/AsynchronousOperation.m
Based on that "blueprint" for your custom operations, it's very trivial to achieve what you want, i.e.:
#interface PressDownAnimationOperation : AsynchronousOperation
- (instancetype)initWithView:(UIView *)view;
#end
#implementation PressDownAnimationOperation {
UIView *_view;
}
- (instancetype)initWithView:(UIView *)view {
self = [super init];
if(self) {
_view = view;
}
return self;
}
- (void)main {
// dispatch UIKit related stuff on main thread
dispatch_async(dispatch_get_main_queue(), ^{
// animate
[UIView animateWithDuration:0.2 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{
_view.layer.transform = CATransform3DMakeScale(0.8, 0.8, 1);
} completion:^(BOOL finished){
// mark operation as finished
[self completeOperation];
}];
});
}
#end
Now in order to run animations you need to create NSOperationQueue. You can keep it within your view controller, i.e.:
#implementation ViewController {
NSOperationQueue *_animationQueue;
}
- (void)viewDidLoad {
[super viewDidLoad];
_animationQueue = [[NSOperationQueue alloc] init];
// limit queue to run single operation at a time
_animationQueue.maxOperationCount = 1;
}
#end
Now when you want to chain animations, you simply create new operation, add it to queue and that's it, i.e.:
- (void)pressedDown {
NSOperation *animationOperation = [[PressDownAnimationOperation alloc] init];
[_animationQueue addOperation:animationOperation];
}
If user taps too fast and you notice that your operation queue is clogged with animations, you can simply cancel all animations before adding new one, i.e.:
[_animationQueue cancelAllOperations];

UIPercentDrivenInteractiveTransition yielding extraneous animation when done

I'm using an interactive custom push transition with a UIPercentDrivenInteractiveTransition. The gesture recognizer successfully calls the interaction controller's updateInteractiveTransition. Likewise, the animation successfully completes when I call the interaction controller's finishInteractiveTransition.
But, sometimes I get a extra bit of distracting animation at the end (where it seems to repeat the latter part of the animation). With reasonably simple animations, I rarely see this symptom on the iPhone 5 (though I routinely see it on the simulator when working on slow laptop). If I make the animation more computationally expensive (e.g. lots of shadows, multiple views animating different directions, etc.), the frequency of this problem on the device increases.
Has anyone else seen this problem and figured out a solution other than streamlining the animations (which I admittedly should do anyway) and/or writing my own interaction controllers? The UIPercentDrivenInteractiveTransition approach has a certain elegance to it, but I'm uneasy with the fact that it misbehaves non-deterministically. Have others seen this behavior? Does anyone know of other solutions?
To illustrate the effect, see the image below. Notice how the second scene, the red view, when the animation finishes, seems to repeat the latter part of its animation a second time.
This animation is generated by:
repeatedly calling updateInteractiveTransition, progressing update from 0% to 40%;
momentarily pausing (so you can differentiate between the interactive transition and the completion animation resulting from finishInteractiveTransition);
then calling finishInteractiveTransition to complete the animation; and
the animation controller's animation's completion block calls completeTransition for the transitionContext, in order to clean everything up.
Doing some diagnostics, it appears that it is this last step that triggers that extraneous bit of animation. The animation controller's completion block is called when the animation is finished, but as soon as I call completeTransition, it sometimes repeats the last bit of the animation (notably when using complex animations).
I don't think it's relevant, but this is my code for configuring the navigation controller to perform interactive transitions:
- (void)viewDidLoad
{
[super viewDidLoad];
self.navigationController.delegate = self;
self.interationController = [[UIPercentDrivenInteractiveTransition alloc] init];
}
- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
animationControllerForOperation:(UINavigationControllerOperation)operation
fromViewController:(UIViewController*)fromVC
toViewController:(UIViewController*)toVC
{
if (operation == UINavigationControllerOperationPush)
return [[PushAnimator alloc] init];
return nil;
}
- (id <UIViewControllerInteractiveTransitioning>)navigationController:(UINavigationController*)navigationController
interactionControllerForAnimationController:(id <UIViewControllerAnimatedTransitioning>)animationController
{
return self.interationController;
}
My PushAnimator is:
#implementation PushAnimator
- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
return 5.0;
}
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
UIViewController* toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIViewController* fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
[[transitionContext containerView] addSubview:toViewController.view];
toViewController.view.frame = CGRectOffset(fromViewController.view.frame, fromViewController.view.frame.size.width, 0);;
[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
toViewController.view.frame = fromViewController.view.frame;
} completion:^(BOOL finished) {
[transitionContext completeTransition:![transitionContext transitionWasCancelled]];
}];
}
#end
Note, when I put logging statement where I call completeTransition, I can see that this extraneous bit of animation happens after I call completeTransition (even though the animation was really done at that point). This would suggest that that extra animation may have been a result of the call to completeTransition.
FYI, I've done this experiment with a gesture recognizer:
- (void)handlePan:(UIScreenEdgePanGestureRecognizer *)gesture
{
CGFloat width = gesture.view.frame.size.width;
if (gesture.state == UIGestureRecognizerStateBegan) {
[self performSegueWithIdentifier:#"pushToSecond" sender:self];
} else if (gesture.state == UIGestureRecognizerStateChanged) {
CGPoint translation = [gesture translationInView:gesture.view];
[self.interactionController updateInteractiveTransition:ABS(translation.x / width)];
} else if (gesture.state == UIGestureRecognizerStateEnded ||
gesture.state == UIGestureRecognizerStateCancelled)
{
CGPoint translation = [gesture translationInView:gesture.view];
CGPoint velocity = [gesture velocityInView:gesture.view];
CGFloat percent = ABS(translation.x + velocity.x * 0.25 / width);
if (percent < 0.5 || gesture.state == UIGestureRecognizerStateCancelled) {
[self.interactionController cancelInteractiveTransition];
} else {
[self.interactionController finishInteractiveTransition];
}
}
}
I also did it by calling the updateInteractiveTransition and finishInteractiveTransition manually (eliminating the gesture recognizer from the equation), and it still exhibits this strange behavior:
[self performSegueWithIdentifier:#"pushToSecond" sender:self];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[self.interactionController updateInteractiveTransition:0.40];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[self.interactionController finishInteractiveTransition];
});
});
Bottom line, I've concluded that this is a problem isolated to UIPercentDrivenInteractiveTransition with complex animations. I can minimize the problem by simplifying them (e.g. snapshotting and animated snapshotted views). I also suspect I could solve this by not using UIPercentDrivenInteractiveTransition and writing my own interaction controller, which would do the animation itself, without trying to interpolate the animationWithDuration block.
But I was wondering if anyone has figured out any other tricks to using UIPercentDrivenInteractiveTransition with complex animations.
This problem arises only in simulator.
SOLUTION: self.interactiveAnimator.completionSpeed = 0.999;
bug reported here: http://openradar.appspot.com/14675246
I've seen something similar. I have two possible workarounds. One is to use delayed performance in the animation completion handler:
} completion:^(BOOL finished) {
double delayInSeconds = 0.1;
dispatch_time_t popTime =
dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
BOOL cancelled = [transitionContext transitionWasCancelled];
[transitionContext completeTransition:!cancelled];
});
self.interacting = NO;
}];
The other possibility is: don't use percent-drive animation! I've never had a problem like this when driving the interactive custom animation myself manually.
The reason for this error in my case was setting the frame of the view being animated multiple times. I'm only setting the view frame ONCE and it fixed my issues.
So in this case, the frame of "toViewController.view" was set TWICE, thus making the animation have an unwanted behavior

iOS prevent rotations until after animation completes

I'm creating an iOS app and in one method I have a for loop that does a series of animations that last around 2 seconds.
My problem is that if the user rotates the device while the animations are still in progress, it messes up the formatting for the new orientation (everything works just the way it should if the rotation happens after the animation is complete).
So I was wondering if there is a way to delay rotations
You could have a BOOL instance variable that you update based on whether your animation is complete or not. Then override the shouldAutorotate method and return that BOOL. Might look something like this:
#implementation YourViewController {
BOOL _shouldAutoRotate;
}
-(BOOL)shouldAutorotate {
[super shouldAutorotate];
return _shouldAutoRotate;
}
-(void)yourAnimationMethod {
_shouldAutoRotate = NO;
[UIView animateWithDuration:2.0f animations:^{
//your animations
} completion:^(BOOL finished) {
if(finished) {
_shouldAutoRotate = YES;
}
}];
}

Custom Containers and Custom Transitions

Custom transitions work easily with standard containers and while presenting modal view controllers. But what about using custom transitions with a totally custom container?
I'd like to use the UIViewControllerContextTransitioning protocol with my custom container and take advantage of transitioning and interactive transitions.
In the comment into the header file of UIViewControllerContextTransitioning I read:
// The UIViewControllerContextTransitioning protocol can be adopted by custom
// container controllers. It is purposely general to cover more complex
// transitions than the system currently supports.
but I can't understand how to create a Context Transitioning and start all the custom transition process.
This is very well possible!
have a look at this SO Answer.
You just have to create a viewController conforming to the UIViewControllerContextTransitioning protocol and use the ViewController Containment API (addChildViewController:, willMoveToParentViewController:, and so on).
When you want to start the custom transition, simply call the [animateTransition] Method on your transitionController. From that point on, it's the same as with the Apple-provided API.
Make your custom container fit in with the Transitioning API.
In fact, all the new protocols introduced in iOS7 (UIViewControllerContextTransitioning and so on) are not really needed to implement your own fully custom containerViewController. Its just providing a neat class-relationship and method pool. But you could write that all by yourself and would not need to use any private API.
ViewController Containment (introduced in iOS5) is all you need for this job.
I just tried gave it a try and its even working with interactive transitions.
If you need some sample code please let me know and i'll provide some :)
EDIT
By the way, this is how Facebook and Instagram for iOS is creating their navigation concept. You can scroll away the NavigationBar in these Apps and when a new ViewController is "pushed" the NavigationBar seems to have been reset during the pushing.
Ironically, i asked the exact same question a month ago here on StackOverflow :D
My Question
And I just realized i answered it myself :)
Have a nice day !
In fact, it says so but you are incomplete:
The UIViewControllerContextTransitioning protocol can be adopted by
custom container controllers. It is purposely general to cover
more complex transitions than the system currently supports. For
now, navigation push/pops and UIViewController present/dismiss
transitions can be customized.
That means you can trigger your VC's transitioningDelegate by calling presentViewController:animated:completion: method or you can implement navigationController:animationControllerForOperation:fromViewController:toViewController: in your UINavigationControllerDelegate class and return an object that conforms UIViewControllerAnimatedTransitioning protocol.
To sum up, there are only two ways to provide custom transition. Both requires presenting/pushing a VC while we add subviews to create custom container view controllers.
Probably, Apple will do what they said in the first lines of their statement in header file in the future, but for now what you want to do seems impossible.
From docs UIViewControllerContextTransitioning
Do not adopt this protocol in your own classes, nor should you
directly create objects that adopt this protocol.
Please look at MPFoldTransition, it worked for me.
You can also use the following Category, you can create your own transition using this.
#import <UIKit/UIKit.h>
#interface UIView (Animation)
- (void) moveTo:(CGPoint)destination duration:(float)secs option:(UIViewAnimationOptions)option;
- (void) downUnder:(float)secs option:(UIViewAnimationOptions)option;
- (void) addSubviewWithZoomInAnimation:(UIView*)view duration:(float)secs option:(UIViewAnimationOptions)option;
- (void) removeWithZoomOutAnimation:(float)secs option:(UIViewAnimationOptions)option;
- (void) addSubviewWithFadeAnimation:(UIView*)view duration:(float)secs option:(UIViewAnimationOptions)option;
- (void) removeWithSinkAnimation:(int)steps;
- (void) removeWithSinkAnimationRotateTimer:(NSTimer*) timer;
#end
Implementation :
#import "UIView+Animation.h"
#implementation UIView (Animation)
- (void) moveTo:(CGPoint)destination duration:(float)secs option:(UIViewAnimationOptions)option
{
[UIView animateWithDuration:secs delay:0.0 options:option
animations:^{
self.frame = CGRectMake(destination.x,destination.y, self.frame.size.width, self.frame.size.height);
}
completion:nil];
}
- (void) downUnder:(float)secs option:(UIViewAnimationOptions)option
{
[UIView animateWithDuration:secs delay:0.0 options:option
animations:^{
self.transform = CGAffineTransformRotate(self.transform, M_PI);
self.alpha = self.alpha - 0.5;
}
completion:nil];
}
- (void) addSubviewWithZoomInAnimation:(UIView*)view duration:(float)secs option:(UIViewAnimationOptions)option
{
// first reduce the view to 1/100th of its original dimension
CGAffineTransform trans = CGAffineTransformScale(view.transform, 0.01, 0.01);
view.transform = trans; // do it instantly, no animation
[self addSubview:view];
// now return the view to normal dimension, animating this tranformation
[UIView animateWithDuration:secs delay:0.0 options:option
animations:^{
view.transform = CGAffineTransformScale(view.transform, 100.0, 100.0);
}
completion:nil];
}
- (void) removeWithZoomOutAnimation:(float)secs option:(UIViewAnimationOptions)option
{
[UIView animateWithDuration:secs delay:0.0 options:option
animations:^{
self.transform = CGAffineTransformScale(self.transform, 0.1, 0.1);
}
completion:^(BOOL finished) {
[self removeFromSuperview];
}];
}
// add with a fade-in effect
- (void) addSubviewWithFadeAnimation:(UIView*)view duration:(float)secs option:(UIViewAnimationOptions)option
{
view.alpha = 0.0; // make the view transparent
[self addSubview:view]; // add it
[UIView animateWithDuration:secs delay:0.0 options:option
animations:^{view.alpha = 1.0;}
completion:nil]; // animate the return to visible
}
// remove self making it "drain" from the sink!
- (void) removeWithSinkAnimation:(int)steps
{
//NSTimer *timer;
if (steps > 0 && steps < 100) // just to avoid too much steps
self.tag = steps;
else
self.tag = 50;
[NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:#selector(removeWithSinkAnimationRotateTimer:) userInfo:nil repeats:YES];
}
- (void) removeWithSinkAnimationRotateTimer:(NSTimer*) timer
{
CGAffineTransform trans = CGAffineTransformRotate(CGAffineTransformScale(self.transform, 0.9, 0.9),0.314);
self.transform = trans;
self.alpha = self.alpha * 0.98;
self.tag = self.tag - 1;
if (self.tag <= 0)
{
[timer invalidate];
[self removeFromSuperview];
}
}
#end
I hope it solves your problem. enjoy.:)

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