I have created a simple app with a segmented control at the top. When I click on one of two segments of the control a UIImageView starts to rotate. I have a reset button hooked up to set its transform to CGAffineTransformIdentity.
The problem occurs when the method that does the view rotation animation is called a second time by switching segments back and forth. Hitting reset only removes the most recent animation. I have to switch segments a second time to get the animations to stop with reset entirely.
The following code is called when I select the segment to rotate the UIImageView and obviously called a second time when I click between segments.
// Begin the animation block and set its name
[UIView beginAnimations:#"Rotate Animation" context:nil];
// Set the duration of the animation in seconds (floating point value)
[UIView setAnimationDuration:0.5];
// Set the number of times the animation will repeat (NSIntegerMax setting would repeat indefinately) (floating point value)
[UIView setAnimationRepeatCount:NSIntegerMax];
// Set the animation to auto-reverse (complete the animation in one direction and then do it backwards)
[UIView setAnimationRepeatAutoreverses:YES];
// Animation curve dictates the speed over time of an animation (UIViewAnimationCurveEaseIn, UIViewAnimationCurveEaseOut, UIViewAnimationCurveEaseInOut, UIViewAnimationCurveLinear)
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
// Changes the imageViews transform property to rotate the view using CGAffineTransformRotate
// CGAffineTransformRotate(transformToStartFrom, angleToRotateInRadians)
// Starting transform property can be set to CGAffineTransformIdentity to start from views original transform state
// This can also be done using CGAffineTransformMakeRotation(angleInRadians) to start from the IdentityTransform without implicitly stating so
self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, degreesToRadians(90));
[UIView commitAnimations];
The reset button calls this code -
self.imageView.transform = CGAffineTransformIdentity;
try this
[UIView animateWithDuration:0.2 animations:^() {
self.imageView.transform = CGAffineTransformIdentity;
}];
Related
I have four UIViews, positions on the four sides of my full view, e.g.
View 3
View 4 View 2
View 1
(Note that the bottom view is offset a little bit)
They are all 44x44 pixels and look exactly the same.
I have the views move counter clockwise to the next view's location (i.e. View 1 moves to View 2, View 2 moves to View 3, etc.), and View 4 moves to View 1, but not offset. This part works normally, the code is as follows:
[UIView animateWithDuration:0.5 animations:^{
[view1 setFrame:view2.frame];
[view2 setFrame:view3.frame];
[view3 setFrame:view4.frame];
[view4 setFrame:centerFrame];
} completion:^(BOOL finished) {
[self reloadData];
}];
centerFrame is view1's frame not offset.
In the method reloadData, the frames are move back to their original positions, and, because they all look the same, the only thing that users should see is the movement of the bottom view back to its offset position (although it is really changing from view4 to view1). This change looks a little bit sudden, and I wanted to animate it, but I don't want the views to move back, just cross dissolve, so that only the bottom view looks like it changed. I've tried:
[UIView transitionWithView:self.view duration:1.0 options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
// Reset frames
} completion:nil];
and
[UIView animateWithDuration:1.0 delay:0.0 options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
// Reset frames
} completion:nil];
but both move the views. So my question,
How do I animate a UIView frame change with a cross dissolve animation instead of moving between the points?
Thanks in advance!
You can animated alpha = 0, update the frames in the completion block and then animated alpha = 1. Make the duration of each animation block 1/2 the usual so together they'll take the same time as the rotation event.
If you want to do a simultaneous dissolve then duplicate all the views, set their alpha = 0, update their frames and then animate the alpha of both groups:
old views'.alpha = 0new views'.alpha = 1
a third solution - group all the views in a subview, copy the whole hierarchy and then animate the transition between them using options:UIViewAnimationOptionTransitionCrossDissolve
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 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 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 have a problem with a UIView-subclass object that I am rotating using Core Animation in response to a UISwipeGesture.
To describe the context: I have a round dial that I have drawn in CG and added to the main view as a subview.
In response to swipe gestures I am instructing it to rotate 15 degrees in either direction dependent on whether it;s a left or right swipe.
The problem that it will only rotate each way once. Subsequent gestures are recognised (evident from other actions that are triggered) but the animation does not repeat. I can go left once then right once. But trying to go in either direction multiple times doesn't work. Here's the relevant code, let me know your thoughts...
- (IBAction)handleLeftSwipe:(UISwipeGestureRecognizer *)sender
{
if ([control1 pointInside:[sender locationInView:control1] withEvent:nil])
{
//updates the display value
testDisplay.displayValue = testDisplay.displayValue + 0.1;
[testDisplay setNeedsDisplay];
//rotates the dial
[UIView animateWithDuration:0.25 animations:^{
CGAffineTransform xform = CGAffineTransformMakeRotation(radians(+15));
control1.transform = xform;
[control1 setNeedsDisplay];
}];
}
CGAffineTransform xform = CGAffineTransformMakeRotation(radians(+15));
Do you keep a total of how far the rotation is. CGAffineTransformMakeRotation are not additive. Only the most recent is used. So you are setting it to 15 each time, not 15 more each time.
Here's a super simple example of rotating a view cumulatively. This rotates the view by 180 degrees each button press.
- (IBAction) onRotateMyView: (id) sender
{
[UIView animateWithDuration:0.3 animations:^{
myView.transform = CGAffineTransformMakeRotation(M_PI/2*rotationCounter);
} completion:^(BOOL finished){
//No nothing
}];
++rotationCounter;
}