I'm looking for an equivalent core animation for the following UIView animation?
[UIView animateWithDuration:0.25 animations:^(void) {
cell.frame = newCellFrame;
} completion:^(BOOL finished) {
[UIView animateWithDuration:0.25 animation:^(void) {
cell.frame = finalCellFrame;
}];
}];
What I would like to know in particular is how you mimic the "completion" part of this animation with core animation. Is the only option to use core animation delegation or is there a solution as elegant as the above code snippet?
In CoreAnimation it's done with delegates. You can set a delegate on your CAAnimation/CABasicAnimation instance, and the animation will make animationDidStart: and animationDidStop:finished: callbacks to you.
Related
I am using Autolayout and animating by changing the constraints, however, in iOS7 the view simply jumps to the end position - in iOS6 I get a nice animation.
Is should be noted these views are UICollectionViews and I have checked the Storyboard and there are no Layout errors.
All I can think is there is something and am or am not setting on the Storyboard or something that I am doing wrong with the Constant settings in the Storyboard.
primaryMenuYContraints.constant = BUTTOMX;;
leftMenuYContraints.constant = 136.0f;
leftMenuBottomConstraint.constant = 5.0f;
[UIView animateWithDuration:0.7f
delay:0.0f
options:UIViewAnimationOptionCurveLinear
animations:^
{
// Move in menus
[self.primaryOptionCollection layoutIfNeeded];
[self.menuOptionCollection layoutIfNeeded];
}
completion:^(BOOL finished)
{
}];
I changed to and now works in both iOS7 and 6, still not sure why it does/did it though! I still think I am setting something up wrong in the Storyboard. I am add another view (nothing to do with this lot) programmatically so I believe that is based around frames until I convert it (which I am not doing).
primaryMenuYContraints.constant = BUTTOMX;;
leftMenuYContraints.constant = 136.0f;
leftMenuBottomConstraint.constant = 5.0f;
[UIView animateWithDuration:0.7f
delay:0.0f
options:UIViewAnimationOptionCurveLinear
animations:^
{
// Move in menus
[self.view layoutIfNeeded];
}
completion:^(BOOL finished)
{
}];
I have a UIScrollView which contains various subviews (UIImageViews, UILabels and standard UIViews). Some of the UIImageViews are partially covered by other UIViews.
However, when I fade out the UIScrollView, the partially covered parts of the UIImageViews are being exposed for the brief moment of the animation.
I want to be able to fade the scrollview and all it's contents at the same time in the same animation - i.e. not revealing any of the partially covered images.
If it's not possible, I can always add a UIView on top of all the other controls and fade it from alpha 0 upto 1 to hide everything, but I'm sure there's a way to perform a complete fade on a view and all it's subviews.
I tried this:
[UIView beginAnimations:nil context:NULL];
[scrollViewResults setAlpha:0.0f];
[UIView commitAnimations];
And I've tried this:
- (IBAction)questionGroupChanged:(UIButton*)sender {
[UIView beginAnimations:nil context:NULL];
[self fadeViewHierarchy:scrollViewResults toAlpha:0.0f];
[UIView commitAnimations];
}
- (void)fadeViewHierarchy:(UIView*)parentView toAlpha:(float)alpha {
[parentView setAlpha:alpha];
for (UIView *subView in parentView.subviews) {
[self fadeViewHierarchy:subView toAlpha:alpha];
}
}
But I've still not cracked it. Any ideas?
This happens because of the way the compositor works. You need to enable rasterization on the view's layer when fading it in/out:
view.layer.shouldRasterize = YES;
You should probably only enable this for the duration of the animation because it will take up some extra memory and graphics processing time.
Mike's answer is the correct one and he deserves all credit for this. Just to illustrate, it might look like:
- (void)fadeView:(UIView*)view toAlpha:(CGFloat)alpha
{
view.layer.shouldRasterize = YES;
[UIView animateWithDuration:0.75
animations:^{
view.alpha = alpha;
}
completion:^(BOOL finished){
view.layer.shouldRasterize = NO;
}];
}
Thus, using your scrollViewResults, it would be invoked as:
[self fadeView:scrollViewResults toAlpha:0.0f];
Did you try with UIView class methods +animateWithDuration:* (available on iOS 4 and +)
Like :
- (void)fadeAllViews
{
[UIView animateWithDuration:2
animations:^{
for (UIView *view in allViewsToFade)
view.alpha = 0.0;
}
completion:^(BOOL finished){}
];
}
I have no idea, why it is not working.
All I want to do is a simple UIView animation in the viewDidLoad.
Here's my code:
[UIView animateWithDuration:3.0f animations:^{
[self.headline setCenter:CGPointMake(0.0, 200.0)];
}];
Nothing happens. When I test the general approach of calling a animation method on that particular object like this:
[UIView animateWithDuration:3.0f animations:^{
[self.headline setAlpha:0.0];
}];
it works!!! Why am I not able to move the view across the screen? I am using latest Xcode 4.5.
Thanks for any advice!
UPDATE:
When I add a view manually in code it works. But for the UIViews I create as Outlets in the Interface Builder it doesn't work.
UILabel *testLabel = [[UILabel alloc] initWithFrame:CGRectMake(0.0, 0.0, 200.0, 100.0)];
testLabel.backgroundColor = [UIColor redColor];
[self.view addSubview:testLabel];
[UIView animateWithDuration:3.0 animations:^{
testLabel.center = CGPointMake(0.0, 200);
}];
So obviously I am doing something wrong in the .xib file
Dont do it in viewDidLoad. The view is not pressent at that time yet.
Try it in viewDidAppear.
Well, I think the reason for the missing animation was the fact that I called a different push navigation animation from the view controller that was pushing the actual view on screen:
- (IBAction)goForSelection:(id)sender
{
SelectionViewController *selectionViewController = [[SelectionViewController alloc] initWithNibName:#"SelectionViewController" bundle:nil];
//[self.navigationController pushViewController:selectionViewController animated:YES];
[UIView transitionWithView:self.navigationController.view duration:1.0 options:UIViewAnimationOptionTransitionFlipFromRight animations:^{
[self.navigationController pushViewController:selectionViewController animated:NO];
} completion:^(BOOL finished) {
[selectionViewController startIntroAnimation];
}];
}
First I checked what happens when I use the default navigation controller segue. And to my surprise the animation did start. Then I inserted the call to the [selectionViewController startIntroAnimation] to the completion block and this works as well.
I was informed recently by meronix that use of beginAnimations is discouraged. Reading through the UIView class reference I see that this is indeed true - according to the Apple class ref:
Use of this method is discouraged in iOS 4.0 and later. You should use
the block-based animation methods to specify your animations instead.
I see that a large number of other methods - which I use frequently - are also "discouraged" which means they'll be around for iOS 6 (hopefully) but probably will be deprecated/removed eventually.
Why are these methods being discouraged?
As a side note, right now I'm using beginAnimations in all sorts of apps, most commonly to move the view up when a keyboard is shown.
//Pushes the view up if one of the table forms is selected for editing
- (void) keyboardDidShow:(NSNotification *)aNotification
{
if ([isRaised boolValue] == NO)
{
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.25];
self.view.center = CGPointMake(self.view.center.x, self.view.center.y-moveAmount);
[UIView commitAnimations];
isRaised = [NSNumber numberWithBool:YES];
}
}
Not sure how to duplicate this functionality with block-based methods; a tutorial link would be nice.
They are discouraged because there is a better, cleaner alternative
In this case all a block animation does is automatically wrap your animation changes (setCenter: for example) in begin and commit calls so you dont forget. It also provides a completion block, which means you don't have to deal with delegate methods.
Apple's documentation on this is very good but as an example, to do the same animation in block form it would be
[UIView animateWithDuration:0.25 animations:^{
self.view.center = CGPointMake(self.view.center.x, self.view.center.y-moveAmount);
} completion:^(BOOL finished){
}];
Also ray wenderlich has a good post on block animations: link
Another way is to think about a possible implementation of block animations
+ (void)animateWithDuration:(NSTimeInterval)duration animations:(void (^)(void))animations
{
[UIView beginAnimations];
[UIView setAnimationDuration:duration];
animations();
[UIView commitAnimations];
}
Check out this method on UIView, which makes it quite simple. The trickiest part nowadays is not allowing a block to have a strong pointer to self:
//Pushes the view up if one of the table forms is selected for editing
- (void) keyboardDidShow:(NSNotification *)aNotification
{
if ([isRaised boolValue] == NO)
{
__block UIView *myView = self.view;
[UIView animateWithDuration:0.25 animations:^(){
myView.center = CGPointMake(self.view.center.x, self.view.center.y-moveAmount);
}];
isRaised = [NSNumber numberWithBool:YES];
}
}
[UIView animateWithDuration:1.0 animations:^(void) {
im.transform = CGAffineTransformIdentity;
} completion:^(BOOL finished) {
[UIView animateWithDuration:1.0 delay:1.0 options:UIViewAnimationCurveEaseOut animations:^(void) {
im.alpha = 0.0;
} completion:^(BOOL finished) {
[im removeFromSuperview];
}];
}];
The code is for animating UIImageView, that I know;
I want to know the calling mechanism, as I haven't seen this kind of function call for the very first time.
Mainly, What is ^(void) and why im.transform = CGAffineTransformIdentity; passed to it?
I have gone thorugh Apple docs, to find anything related to this function call, and I got it too, but I didn't get any idea from there; or I might have been to wrong section.
Can anyone here guide me to this?
This is called a block, and was introduced in iOS 4 and Mac OS X 10.6.
Here are some links where you can learn more about them:
Apple's Documentation - Blocks Programming Topics
Ask Big Nerd Ranch: Blocks in Objective-C
Programming with C Blocks
Introduction to Blocks in Objective-C – Part 1
The above example should read as follows:
// Start an animation over the next 1 second
[UIView animateWithDuration:1.0 animations:^(void) {
// For this animation, animate from the current value of im.transform back to the identity transform
im.transform = CGAffineTransformIdentity;
} completion:^(BOOL finished) { // At the completion of the first animation...
// Wait 1 second, then start another 1-second long animation
[UIView animateWithDuration:1.0 delay:1.0 options:UIViewAnimationCurveEaseOut animations:^(void) {
im.alpha = 0.0; // Fade out im during this animation
} completion:^(BOOL finished) { // When you complete this second animation
[im removeFromSuperview]; // Remove im from its superview
}];
}];
So you will have one second where im animates the removal of its transform, a one second delay, and then a one second fadeout of im.