I add multiple MKCircle's and one MKPolyline to an MKMapView. In an animationWithDuration I change the alpha of my instance of MKMapView from 1 to 0. The MKMapView disapears as expected, but at the start of the animation the MKOverlays (MKCircle's and MKPolyline) are jumping a few pixels.
self.routeView.alpha = 0;
[UIView animateWithDuration:2 animations:^{
self.routeView.alpha = 0;
} completion:^(BOOL finished) {
}];
I added an example video showing the problem. In this video you see the change of alpha from 1 to 0 in 2 seconds en after the animation finished you see animating it back to 1 in 2 seconds. At the beginning of the first animation and at the end of the second you see a little jump.
example video
In the simulator you can't reproduce this problem, because the overlays disappear immediately. You should run it on a device instead.
Does anyone know what causes this problem and how it can be solved?
Try converting your animation block to the older syntax. For my case, the block style was not working, but the old style did. This fixed my animation of the alpha.
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:2];
self.routeView.alpha = 0.0;
[UIView commitAnimations];
Related
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 testing my apps for the release of IOS 8. I noticed that after I performed an animation block, the animation resets if I update the text of any label. I ran a simple example with one method shown below. Running this example results in the following:
Clicking myButton the first time- animation runs but resets when the label text is changed.
Clicking myButton the second time - animation runs but does not reset to original position.
It seems like this happens because the label text doesn't change. If I completely remove the line updating the text, this also stops the animation from resetting at the end.
I would like to fix this so that when the method runs, the label text can be updated without resetting the animation.
- (IBAction)move:(id)sender {
[UIView animateWithDuration:0.4 delay:0.0
options:UIViewAnimationOptionBeginFromCurrentState
animations:^{
self.myButton.center = CGPointMake(200, 300);
}completion:^(BOOL finished){
if(finished){
self.myLabel.text=#"moved";
}
}];
}
This problem can be caused by having Auto Layout set on the UIView. Strictly speaking, if you're using Auto Layout, then you shouldn't animate the absolute position of objects -- you should animate their constraints instead.
Changing the label text once your animation is underway triggers a layout refresh, and iOS shuffles everything around to comply with the original view constraints. (I suspect this is a behavioural change from iOS7).
Quick fix: un-check Auto Layout on the View, and this should work as expected.
Try this. Put the desired animation in the finish block also.
- (IBAction)move:(id)sender {
[UIView animateWithDuration:0.4 delay:0.0
options:UIViewAnimationOptionBeginFromCurrentState
animations:^{
self.myButton.center = CGPointMake(200, 300);
}completion:^(BOOL finished){
if(finished){
self.myLabel.text=#"moved";
self.myButton.center = CGPointMake(200, 300);
}
}];
}
I am trying to animate a transform of a UIButton with CGAffineTransformRotate, and while it is performing the animation properly, it shifts the button about 15 pixels down and to the left before doing it. Here's the code performing the animated transformation:
[UIView animateWithDuration:0.5 delay:0.0 options:UIViewAnimationOptionTransitionNone
animations:^{
self.addCloseButton.transform = CGAffineTransformRotate(self.addCloseButton.transform, degreesToRadians(45));
}
completion:nil];
When I reverse the transformation it does the same thing except it shifts it back to its original position before animating (15 pixels up and 15 pixels to the right), and I do that with this code:
[UIView animateWithDuration:0.5 delay:0.0 options:UIViewAnimationOptionTransitionNone
animations:^{
self.addCloseButton.transform = CGAffineTransformIdentity;
}
completion:nil];
Why would this shift occur? The button was created using interface builder, and the shift happens immediately even if I set the animation duration higher or add a delay.
I figured it out: turns out having "Use Autolayout" selected on my xib (which adds a bunch of auto constraints) messes things up when trying to use transforms. Turning it off fixed my problem.
It is posible to fix this while still using auto layout and storyboards. See my answer on this question: https://stackoverflow.com/a/19582959
I am trying to animate the alpha value of a MapKit overlay view (specifically an MKCircleView) in iOS 5 using the following code:
-(void) animateCircle:(MKCircle*)circle onMap:(MKMapView*) mapView
{
MKCircleView * circleView = (MKCircleView*) [mapView viewForOverlay:circle];
UIViewAnimationOptions options = UIViewAnimationOptionCurveEaseInOut|UIViewAnimationOptionTransitionNone;
[UIView animateWithDuration:5.0
delay:0.0
options:options
animations:^(void) { circleView.alpha = 0.9; }
completion:^(BOOL finished) {}
];
}
The alpha value of the overlay is changing as I want, but it is jumping there instantaneously rather than animating over the specified duration.
Can anyone suggest what might be wrong? Perhaps animation on overlay views os more complex with blocks than I had thought.
Core Animation has interesting behavior when concurrent animations effect the same view... If you try to animate a view before the view's last animation finished, it will assume you intended the subsequent animation to start from the desired end-state of the initial one. This can result in jumps of frames as well as jumps of alpha values.
In your case, this view is likely being animated by something else. Try locating and removing the other animation / or'ing in UIViewAnimationOptionBeginFromCurrentState to its options.
I have the following block of code to fade out an introView(UIView)
// Hide intro view after 5 seconds
[UIView animateWithDuration: 1.0
delay: 5.0
options: (UIViewAnimationOptionAllowUserInteraction |UIViewAnimationOptionCurveLinear)
animations: ^{
introView.alpha = 0;
}
completion: ^(BOOL finished) {
[introView removeFromSuperview];
}];
I have a skip button inside the introVew but there is no interaction whatsoever, am I missing something? I have to add this is a Universal app targeting 3.2 and I'm using XCode 4.2
Pretty sure this is impossible pre-4.0:
UIView userInteractionEnabled Docs
During an animation, user interactions are temporarily disabled for
all views involved in the animation, regardless of the value in this
property. You can disable this behavior by specifying the
UIViewAnimationOptionAllowUserInteraction option when configuring the
animation.
There seems little point in targeting 3.2 in an app you haven’t released yet.
Are you setting your button alpha to 0?
If yes here is an interesting thing about animation.
What you see on the screen during the animation is not what the application sees.
The moment you set your alpha to 0, the alpha is 0 for that view, even if you are still seeing it on the screen.
Also, a view that has an alpha lower that 0.05 (don't recall the exact number) won't get touch event.
What you can do is to implement the - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event of that view's superview. or the touchesEnded... as you like.
(Assuming that your not setting it's alpha to 0.)
So you can test for touche that occur where the button is, or just remove that button and let any touch on the screen cancel your animation.
You may also be interested in this post:
Core Animation, unexpected animated position and hitTest values
I found another circumstance which could cause this. I haven't seen this answer anywhere else. It does not deal with alpha at all.
If you use a delay in the call to UIView.animate(), then even if you specify the .allowUserInteraction option, the view does NOT receive touches during the delay period. I have no idea why, but I could help it by moving the code block to another function, and using a performSelector after the same delay seconds, and in the block I run the code without delay.
I had the same problem with a button that I animated with changing the alpha. Cueing off VinceBurn's answer...
What you see on the screen during the animation is not what the application sees. The moment >you set your alpha to 0, the alpha is 0 for that view, even if you are still seeing it on the >screen.
AND view that have an alpha lower that 0.05 (don't recall the exact number) won't get touch >event.
… the simple solution of just making the minimum alpha 0.1 instead of 0.0 worked for me:
[UIView animateWithDuration:0.5
delay:0.0
options:UIViewAnimationOptionCurveEaseInOut | UIViewAnimationOptionRepeat | UIViewAnimationOptionAutoreverse | UIViewAnimationOptionAllowUserInteraction
animations:^{
self.myButton.alpha = 0.1f;
}
completion:^(BOOL finished){
}]
Button registered the touchUpInside all the time with no additional method needed, and there was virtually no difference in appearance from taking the alpha to zero.
This won't work in iOS 3.2 since Blocks are only available in iOS4
you will have to use the standard animation techniques, in a separate thread so that you don't block the interface
[UIView beginAnimations:nil context:nil];
[UIView setAnimationTransition: UIViewAnimationTransitionFlipFromLeft forView:view cache:YES];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationDuration:1.0];
[view1 setHidden:TRUE];
[UIView commitAnimations];