Animate UIView using Core Animation? - ios

I am having a little trouble getting a UiView to animate properly using core animation. Here is my code:
CABasicAnimation* animation = [CABasicAnimation animationWithKeyPath:#"position"];
[animation setFromValue:[NSValue valueWithCGPoint:self.view.layer.position]];
[animation setToValue:[NSValue valueWithCGPoint:CGPointMake(250, self.view.layer.position.y)]]; //I want to move my UIView 250 pts to the right
[animation setDuration:1];
[animation setDelegate:self]; //where self is the view controller of the view I want to animate
[animation setRemovedOnCompletion:NO];
[self.view.layer addAnimation:animation forKey:#"toggleMenu"]; //where self.view returns the view I want to animate
I have also implemented the following delegate method:
-(void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag{
if(flag)
[self.view.layer setTransform:CATransform3DMakeTranslation(250, 0, 0)]; //set layer to its final position
}
I am trying to make it so that the UIView moves 250 points to the right. However, when the animation is triggered, my view starts to move but the animations seems to end before the view moves 250 points to the right, resulting in the UIView 'teleporting' to its final position. I can't seem to figure out what is causing this behavior.
I have also tried using the UIView method +(void)animateWithDuration:animations: and this approach works perfectly. However, I am trying to achieve a subtle 'bounce' effect and I'd much rather achieve it using the setTimingFunction:functionWithControlPoints: method rather than having multiple callbacks.
Any help and suggestions are appreciated.

Try like this
CABasicAnimation *rotationAnimation;
rotationAnimation = [CABasicAnimation animationWithKeyPath:#"position"];
rotationAnimation.fromValue=[NSValue valueWithCGPoint:CGPointMake([view center].x, [view center].y)];
rotationAnimation.toValue=[NSValue valueWithCGPoint:CGPointMake([view center].x+250, [view center].y)];
rotationAnimation.duration = 1.0+i;
rotationAnimation.speed = 3.0;
rotationAnimation.cumulative = YES;
rotationAnimation.repeatCount = 1.0;
rotationAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
[view.layer addAnimation:rotationAnimation forKey:#"position"];

If you are aiming to move your view, your code should go like this:
CABasicAnimation* animation = [CABasicAnimation animationWithKeyPath:#"position"];
[animation setFromValue:[NSValue valueWithCGPoint:self.view.layer.position]];
CGPoint p = self.view.layer.position;
p.x += 250;
self.view.layer.position = p;
[animation setDuration:1];
[animation setRemovedOnCompletion:NO];
[self.view.layer addAnimation:animation forKey:#"toggleMenu"];
You should really change your view's(layer's) position. Otherwise, your view will stay still at its previous position when your animation removed. That's a difference between UIView Animation and Core Animation.

CABasicAnimation* animation = [CABasicAnimation animationWithKeyPath:#"position"];
[animation setFromValue:[NSValue valueWithCGPoint:view.layer.position]];
CGPoint newPosition = CGPointMake(200, 300);
view.layer.position = p;
[animation setDuration:0.5f];
[animation setRemovedOnCompletion:NO];
[group setFillMode:kCAFillModeForwards];
[[view layer] addAnimation:animation forKey:#"position"];

Related

Flipping the UILabel

I want to use the CABasicAnimation to flip the UILabel. Animation will repeat forever and will change the text of UILabel between two different values.
- (void)animateLabel
{
[self.myLabel.layer addAdnimation:[self labelAnimation] forKey:#"flip"];
}
- (CAAnimation*)labelAnimation
{
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:#"transform"];
[animation setRepeatCount:NSIntegerMax];
[animation setAutoreverses:YES];
[animation setDuration:2.0];
[animation setDelegate:self];
CATransform3D transform = CATransform3DMakeRotation(M_PI_2, 1, 0, 0);
[animation setToValue:[NSValue valueWithCATransform3D:transform]];
return animation;
}
Now, I tried using the delegate but the delegate method is only when the animation first begins. Rather I need to be able to know the the label completes one cycle. Is there some convenience method or way to do it with CALayer or do I have to use CADisplay link or timer ? I would like to thank you before hand for helping me.
To get notified on each cycle, setRepeatsCount to 1. You'll then get notified in the delegate animationDidStop:finished. You would then simply add the same animation again.
- (void)animateLabel
{
[self.myLabel.layer addAdnimation:[self labelAnimation] forKey:#"flip"];
}
- (void)animationDidStop:(CAAnimation *)theAnimation finished:(BOOL)flag
{
[self animateLabel];
// do other stuff
}
- (CAAnimation*)labelAnimation
{
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:#"transform"];
[animation setRepeatCount:1];
[animation setAutoreverses:YES];
[animation setDuration:2.0];
[animation setDelegate:self];
CATransform3D transform = CATransform3DMakeRotation(M_PI_2, 1, 0, 0);
[animation setToValue:[NSValue valueWithCATransform3D:transform]];
return animation;
}
No, this is the way you're supposed to do it according to the documentation.
Setting this property to HUGE_VALF will cause the animation to repeat forever.

CABasicAnimation: What if CAShapeLayer position not changed?

I'm really new on the CABasicAnimation topic. If you want to animate the x
position of an CAShapeLayer from the current x position to a specific x position you should
use the following:
NSLog(#"CABasicAnimation now...");
CABasicAnimation *layerPositionAnimation = [CABasicAnimation animationWithKeyPath:#"position"];
[layerPositionAnimation setDuration:0.330];
[layerPositionAnimation setRemovedOnCompletion: NO];
[layerPositionAnimation setFillMode: kCAFillModeForwards];
[layerPositionAnimation setTimingFunction: [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut]];
[layerPositionAnimation setFromValue:[NSValue valueWithCGPoint:CGPointMake(self.shapeLayer.position.x, self.shapeLayer.position.y)]];
[layerPositionAnimation setToValue:[NSValue valueWithCGPoint:CGPointMake(14.0, self.shapeLayer.position.y)]];
[self.shapeLayer addAnimation:layerPositionAnimation forKey:#"layerPositionAnimation"];
In my case the self.shapeLayer is a CAShapeLayer used as a simple mask:
[[overlayTopShadow layer] setMask:self.shapeLayer];
But what if the animation never happens (x position not changed)? What i'm doing wrong in my code?
Any suggestions, ideas, examples?
Thanks a lot

how to build in and build out a layer?

I want to build in a layer and build out it after 5 seconds. but I don't know how to assign the final value to the layer. my code is as following:
-(CABasicAnimation *) buildIn{
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:#"opacity"];
animation.duration = 2.0f;
[animation setFromValue:[NSNumber numberWithFloat:0.0f]];
[animation setToValue:[NSNumber numberWithFloat:1.0f]];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
return animation;
}
-(CABasicAnimation *) buildOut{
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:#"opacity"];
animation.duration = 2.0f;
animation.beginTime = CACurrentMediaTime() + 5;
[animation setFromValue:[NSNumber numberWithFloat:1.0f]];
[animation setToValue:[NSNumber numberWithFloat:0.0f]];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
return animation;
}
- (IBAction)startAnimation:(id)sender {
[self.textView.layer addAnimation:[self buildIn] forKey:#"transparent"];
self.textView.layer.opacity = 1.0f;//I need to set the opacity to 1 after buildIn animation
[self.textView.layer addAnimation:[self buildOut] forKey:#"transparent"];
self.textView.layer.opacity = 0.0f;//ERROR: this is the final layer value, but I need to assign it after the build out animation, not here.
}
I think I can use a completion block to do it, but I can't find it.
If you set a delegate on your buildIn animation, then when it is finished the -animationDidStop:finished: message will be sent to the delegate. Then you can start your buildOut animation.
CAAnimation delegate reference

iOS UIView properties don't animate with CABasicAnimation

I can imagine a far amount of sighs when people see this question popup again. However, I have read through a lot of information both here, in the documentation and via Google and still haven't found a solution. So here goes nothing.
I'm trying to recreate the Facebook login screen, where the spacing and position animates with the keyboard to allow the user to still see all the input fields and login button.
This works when I use the kCAFillModeForwards and set removedOnCompletion to NO. But, as said in another thread here on SO, this seems to only visually change properties and the actual tap position isn't changed. So when the user is seemingly tapping an input field, iOS interprets it as a tap on the background.
So I tried setting the new position and size but when I do that the animation doesn't play, it just snaps to the new position. Putting it before the addAnimation call and after it, with and without transactions, it doesn't make any difference.
The delegate methods are still called, but you can't visually see any animation.
if([notification name] == UIKeyboardWillShowNotification) {
CGRect currBounds = self.loginTable.tableHeaderView.layer.bounds;
CGSize newSize = CGSizeMake(self.loginTable.tableHeaderView.bounds.size.width, 60);
CGPoint newPos = CGPointMake(self.loginTable.layer.position.x, self.loginTable.layer.position.x - 50);
//[CATransaction begin];
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:#"bounds.size"];
[animation setToValue:[NSValue valueWithCGSize:newSize]];
[animation setDelegate:self];
[self.loginTable.tableHeaderView.layer addAnimation:animation forKey:#"headerShrinkAnimation"];
CABasicAnimation *formPosAnimation = [CABasicAnimation animationWithKeyPath:#"position"];
[formPosAnimation setToValue:[NSValue valueWithCGPoint:newPos]];
[formPosAnimation setDelegate:self];
//formPosAnimation.removedOnCompletion = NO;
//formPosAnimation.fillMode = kCAFillModeForwards;
[self.loginTable.layer addAnimation:formPosAnimation forKey:#"tableMoveUpAnimation"];
//[CATransaction commit];
[self.loginTable.tableHeaderView.layer setBounds:CGRectMake(currBounds.origin.x, currBounds.origin.y, newSize.width, newSize.height)];
[self.loginTable.layer setPosition:newPos];
}
I have found a way to make it work, can't say if it's the best way to do it but it seems to be working now.
The key thing was to combine almost everything. So I had to keep removedOnCompletion and fillModeon my animations while also updating the position in my animationDidStop method. It works without setting the two animation parameters as well, but you can see a small flicker in the end.
- (void)keyboardWillChange:(NSNotification *)notification {
newSize = CGSizeZero;
newPos = CGPointZero;
if([notification name] == UIKeyboardWillShowNotification) {
newSize = CGSizeMake(self.loginTable.tableHeaderView.bounds.size.width, 60);
newPos = CGPointMake(self.loginTable.layer.position.x, self.loginTable.layer.position.x - 50);
} else {
newSize = CGSizeMake(self.loginTable.tableHeaderView.bounds.size.width, 150);
newPos = CGPointMake(self.loginTable.layer.position.x, self.loginTable.layer.position.x + 50);
}
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:#"bounds.size"];
[animation setToValue:[NSValue valueWithCGSize:newSize]];
[animation setDelegate:self];
animation.removedOnCompletion = NO;
animation.fillMode = kCAFillModeForwards;
[self.loginTable.tableHeaderView.layer addAnimation:animation forKey:#"headerShrinkAnimation"];
/*-----------------------------*/
CABasicAnimation *formPosAnimation = [CABasicAnimation animationWithKeyPath:#"position"];
[formPosAnimation setToValue:[NSValue valueWithCGPoint:newPos]];
[formPosAnimation setDelegate:self];
formPosAnimation.removedOnCompletion = NO;
formPosAnimation.fillMode = kCAFillModeForwards;
[self.loginTable.layer addAnimation:formPosAnimation forKey:#"tableMoveUpAnimation"];
}
- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag {
NSLog(#"Animation did stop");
CGRect currBounds = self.loginTable.tableHeaderView.layer.bounds;
[self.loginTable.tableHeaderView.layer setBounds:CGRectMake(currBounds.origin.x, currBounds.origin.y, newSize.width, newSize.height)];
[self.loginTable.layer setPosition:newPos];
[self.loginTable.tableHeaderView.layer removeAnimationForKey:#"headerShrinkAnimation"];
[self.loginTable.layer removeAnimationForKey:#"tableMoveUpAnimation"];
}

How to do a curve/arc animation with CAAnimation?

I have an user interface where an item get deleted, I would like to mimic the "move to folder" effect in iOS mail. The effect where the little letter icon is "thrown" into the folder. Mine will get dumped in a bin instead.
I tried implementing it using a CAAnimation on the layer. As far as I can read in the documentations I should be able to set a byValue and a toValue and CAAnimation should interpolate the values. I am looking to do a little curve, so the item goes through a point a bit above and to the left of the items start position.
CABasicAnimation* animation = [CABasicAnimation animationWithKeyPath:#"position"];
[animation setDuration:2.0f];
[animation setRemovedOnCompletion:NO];
[animation setFillMode:kCAFillModeForwards];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName: kCAMediaTimingFunctionEaseOut]];
[animation setFromValue:[NSValue valueWithCGPoint:fromPoint]];
[animation setByValue:[NSValue valueWithCGPoint:byPoint]];
[animation setToValue:[NSValue valueWithCGPoint:CGPointMake(512.0f, 800.0f)]];
[animation setRepeatCount:1.0];
I played around with this for some time, but it seems to me that Apple means linear interpolation.
Adding the byValue does not calculate a nice arc or curve and animate the item through it.
How would I go about doing such an animation?
Thanks for any help given.
Using UIBezierPath
(Don't forget to link and then import QuartzCore, if you're using iOS 6 or prior)
Example code
You could use an animation that will follow a path, conveniently enough, CAKeyframeAnimation supports a CGPath, which can be obtained from an UIBezierPath. Swift 3
func animate(view : UIView, fromPoint start : CGPoint, toPoint end: CGPoint)
{
// The animation
let animation = CAKeyframeAnimation(keyPath: "position")
// Animation's path
let path = UIBezierPath()
// Move the "cursor" to the start
path.move(to: start)
// Calculate the control points
let c1 = CGPoint(x: start.x + 64, y: start.y)
let c2 = CGPoint(x: end.x, y: end.y - 128)
// Draw a curve towards the end, using control points
path.addCurve(to: end, controlPoint1: c1, controlPoint2: c2)
// Use this path as the animation's path (casted to CGPath)
animation.path = path.cgPath;
// The other animations properties
animation.fillMode = kCAFillModeForwards
animation.isRemovedOnCompletion = false
animation.duration = 1.0
animation.timingFunction = CAMediaTimingFunction(name:kCAMediaTimingFunctionEaseIn)
// Apply it
view.layer.add(animation, forKey:"trash")
}
Understanding UIBezierPath
Bezier paths (or Bezier Curves, to be accurate) work exactly like the ones you'd find in photoshop, fireworks, sketch... They have two "control points", one for each vertex. For example, the animation I just made:
Works the bezier path like that. See the documentation on the specifics, but it's basically two points that "pull" the arc towards a certain direction.
Drawing a path
One cool feature about UIBezierPath, is that you can draw them on screen with CAShapeLayer, thus, helping you visualise the path that it will follow.
// Drawing the path
let *layer = CAShapeLayer()
layer.path = path.cgPath
layer.strokeColor = UIColor.black.cgColor
layer.lineWidth = 1.0
layer.fillColor = nil
self.view.layer.addSublayer(layer)
Improving the original example
The idea of calculating your own bezier path, is that you can make the completely dynamic, thus, the animation can change the curve it's going to do, based on multiple factors, instead of just hard-coding as I did in the example, for instance, the control points could be calculated as follows:
// Calculate the control points
let factor : CGFloat = 0.5
let deltaX : CGFloat = end.x - start.x
let deltaY : CGFloat = end.y - start.y
let c1 = CGPoint(x: start.x + deltaX * factor, y: start.y)
let c2 = CGPoint(x: end.x , y: end.y - deltaY * factor)
This last bit of code makes it so that the points are like the previous figure, but in a variable amount, respect to the triangle that the points form, multiplied by a factor which would be the equivalent of a "tension" value.
You are absolutely correct that animating the position with a CABasicAnimation causes it to go in a straight line. There is another class called CAKeyframeAnimation for doing more advanced animations.
An array of values
Instead of toValue, fromValue and byValue for basic animations you can either use an array of values or a complete path to determine the values along the way. If you want to animate the position first to the side and then down you can pass an array of 3 positions (start, intermediate, end).
CGPoint startPoint = myView.layer.position;
CGPoint endPoint = CGPointMake(512.0f, 800.0f); // or any point
CGPoint midPoint = CGPointMake(endPoint.x, startPoint.y);
CAKeyframeAnimation *move = [CAKeyframeAnimation animationWithKeyPath:#"position"];
move.values = #[[NSValue valueWithCGPoint:startPoint],
[NSValue valueWithCGPoint:midPoint],
[NSValue valueWithCGPoint:endPoint]];
move.duration = 2.0f;
myView.layer.position = endPoint; // instead of removeOnCompletion
[myView.layer addAnimation:move forKey:#"move the view"];
If you do this you will notice that the view moves from the start point in a straight line to the mid point and in another straight line to the end point. The part that is missing to make it arc from start to end via the mid point is to change the calculationMode of the animation.
move.calculationMode = kCAAnimationCubic;
You can control it arc by changing the tensionValues, continuityValues and biasValues properties. If you want finer control you can define your own path instead of the values array.
A path to follow
You can create any path and specify that the property should follow that. Here I'm using a simple arc
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL,
startPoint.x, startPoint.y);
CGPathAddCurveToPoint(path, NULL,
controlPoint1.x, controlPoint1.y,
controlPoint2.x, controlPoint2.y,
endPoint.x, endPoint.y);
CAKeyframeAnimation *move = [CAKeyframeAnimation animationWithKeyPath:#"position"];
move.path = path;
move.duration = 2.0f;
myView.layer.position = endPoint; // instead of removeOnCompletion
[myView.layer addAnimation:move forKey:#"move the view"];
Try this it will solve your problem definitely, I have used this in my project:
UILabel *label = [[[UILabel alloc] initWithFrame:CGRectMake(10, 126, 320, 24)] autorelease];
label.text = #"Animate image into trash button";
label.textAlignment = UITextAlignmentCenter;
[label sizeToFit];
[scrollView addSubview:label];
UIImageView *icon = [[[UIImageView alloc] initWithImage:[UIImage imageNamed:#"carmodel.png"]] autorelease];
icon.center = CGPointMake(290, 150);
icon.tag = ButtonActionsBehaviorTypeAnimateTrash;
[scrollView addSubview:icon];
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
button.center = CGPointMake(40, 200);
button.tag = ButtonActionsBehaviorTypeAnimateTrash;
[button setTitle:#"Delete Icon" forState:UIControlStateNormal];
[button sizeToFit];
[button addTarget:self action:#selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
[scrollView addSubview:button];
[scrollView bringSubviewToFront:icon];
- (void)buttonClicked:(id)sender {
UIView *senderView = (UIView*)sender;
if (![senderView isKindOfClass:[UIView class]])
return;
switch (senderView.tag) {
case ButtonActionsBehaviorTypeExpand: {
CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:#"transform"];
anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
anim.duration = 0.125;
anim.repeatCount = 1;
anim.autoreverses = YES;
anim.removedOnCompletion = YES;
anim.toValue = [NSValue valueWithCATransform3D:CATransform3DMakeScale(1.2, 1.2, 1.0)];
[senderView.layer addAnimation:anim forKey:nil];
break;
}
case ButtonActionsBehaviorTypeAnimateTrash: {
UIView *icon = nil;
for (UIView *theview in senderView.superview.subviews) {
if (theview.tag != ButtonActionsBehaviorTypeAnimateTrash)
continue;
if ([theview isKindOfClass:[UIImageView class]]) {
icon = theview;
break;
}
}
if (!icon)
return;
UIBezierPath *movePath = [UIBezierPath bezierPath];
[movePath moveToPoint:icon.center];
[movePath addQuadCurveToPoint:senderView.center
controlPoint:CGPointMake(senderView.center.x, icon.center.y)];
CAKeyframeAnimation *moveAnim = [CAKeyframeAnimation animationWithKeyPath:#"position"];
moveAnim.path = movePath.CGPath;
moveAnim.removedOnCompletion = YES;
CABasicAnimation *scaleAnim = [CABasicAnimation animationWithKeyPath:#"transform"];
scaleAnim.fromValue = [NSValue valueWithCATransform3D:CATransform3DIdentity];
scaleAnim.toValue = [NSValue valueWithCATransform3D:CATransform3DMakeScale(0.1, 0.1, 1.0)];
scaleAnim.removedOnCompletion = YES;
CABasicAnimation *opacityAnim = [CABasicAnimation animationWithKeyPath:#"alpha"];
opacityAnim.fromValue = [NSNumber numberWithFloat:1.0];
opacityAnim.toValue = [NSNumber numberWithFloat:0.1];
opacityAnim.removedOnCompletion = YES;
CAAnimationGroup *animGroup = [CAAnimationGroup animation];
animGroup.animations = [NSArray arrayWithObjects:moveAnim, scaleAnim, opacityAnim, nil];
animGroup.duration = 0.5;
[icon.layer addAnimation:animGroup forKey:nil];
break;
}
}
}
I found out how to do it. It's really possible to animate X and Y separately. If you animate them over the same time (2.0 seconds below) and set a different timing function, it will make it look like it moves in an arc instead of a straight line from start to finish values. To adjust the arc you'd need to play around with setting a different timing function. Not sure if CAAnimation supports any "sexy" timing functions however.
const CFTimeInterval DURATION = 2.0f;
CABasicAnimation* animation = [CABasicAnimation animationWithKeyPath:#"position.y"];
[animation setDuration:DURATION];
[animation setRemovedOnCompletion:NO];
[animation setFillMode:kCAFillModeForwards];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]];
[animation setFromValue:[NSNumber numberWithDouble:400.0]];
[animation setToValue:[NSNumber numberWithDouble:0.0]];
[animation setRepeatCount:1.0];
[animation setDelegate:self];
[myview.layer addAnimation:animation forKey:#"animatePositionY"];
animation = [CABasicAnimation animationWithKeyPath:#"position.x"];
[animation setDuration:DURATION];
[animation setRemovedOnCompletion:NO];
[animation setFillMode:kCAFillModeForwards];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut]];
[animation setFromValue:[NSNumber numberWithDouble:300.0]];
[animation setToValue:[NSNumber numberWithDouble:0.0]];
[animation setRepeatCount:1.0];
[animation setDelegate:self];
[myview.layer addAnimation:animation forKey:#"animatePositionX"];
Edit:
Should be possible to change timing function by using https://developer.apple.com/library/ios/#documentation/Cocoa/Reference/CAMediaTimingFunction_class/Introduction/Introduction.html (CAMediaTimingFunction inited by functionWithControlPoints:::: )
It's a "cubic Bezier curve". I'm sure Google has answers there. http://en.wikipedia.org/wiki/B%C3%A9zier_curve#Cubic_B.C3.A9zier_curves :-)
I have had a bit similar question several days ago and I implemented it with timer, as Brad says, but not NSTimer. CADisplayLink - that is the timer which should be used for this purpose, as it is synchronized with the frameRate of the application and provides smoother and more natural animation. You can look at my implementation of it in my answer here. This technique really gives much more control on animation than CAAnimation, and is not much more complicated.
CAAnimation can't draw anything since it doesn't even redraw the view. It only moves, deforms and fades what is already drawn.

Resources