UIView not animating constraint change - objective-c

I have a question regarding the UIView method:
+ (void)animateWithDuration:(NSTimeInterval)duration
animations:(void (^)(void))animations
completion:(void (^)(BOOL finished))completion
Basically I am just trying to set a height constraints constant to 0 and have the change look like its slowly shrinking...
My Code looks like this:
[UIView animateWithDuration:0.7
animations:^{
//hide the Title
self.titleCellHeigthConstraint.constant = kLabelHeightZero;
[self.contentView layoutIfNeeded];
}
completion:nil];
Unfortunately it's not animating. It simply makes all changes appear with a little delay (which might be the 0.7 seconds specified in the method).
Now my question is if there is any way to get the UIView to animate the change?
Thanks in Advance!
Edit:
The weird thing is if I reverse the changes in an animated fashion it does it exactly the way I want it. The code I'am using for that is:
//animate layout changes
[UIView animateWithDuration:0.7
animations:^{
//hide activity indicator and label
[self.activityIndicator stopAnimating];
[self.label setHidden:YES];
}
completion:^(BOOL arg0){
[UIView animateWithDuration:0.3
animations:^{
//show title label
self.titleCellHeigthConstraint.constant = kDefaultLabelHeight;
[self.contentView layoutIfNeeded];
}];
}];

You want to change the properties of the UIView not the NSLayoutConstraint in the animation method. I.e. Change the layout constraint's constant before the UIView method and then change the UIView's frame property in the animation method.
This way you won't need to call layoutIfNeeded.

Related

Animating with Auto Layout and iOS7 jumps to end of animation (fine in iOS6)

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)
{
}];

Fading UIView allows subviews to be seen

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){}
];
}

Simple UIView animation move doesn't work

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.

presentModalViewController translucent with previous view in the background

Im trying to present a view translucently and that the previous view sticks around and be that its visible in the background.
I've got
[self presentModalViewController:modalView animation:YES];
and I have the transparency set in the modalView's viewDidLoad, but after modalView gets brought up the previous view disappears. What can I do to keep the other view to stay around in the background?
I have also tried adding it with
[self.view addSubview:modalView.view];
It doesn't cover the whole screen, I would like to be able to solve this problem using presentModalViewController method.
It sounds like you just want a view to be displayed on top of your main view. Modal views are a finicky way of presenting subviews, instead you should look at creating a simple view class to add to your view controller. You can then use [UIView animate...]; method to animate it in and out of view.
To get you started:
- (void)displayViewButtonPressed(id)sender
{
if (!self.topView)
{
UIView *overlayView = [[UIView alloc] initWithFrame:CGRectMake(44.0f, 22.0f, 40.0f, 44.0f];
[overlayView setAlpha:0.0f];
[overlayView setBackgroundColor:[UIColor redColor]];
[self setTopView:overlayView];
[overlayView release];
}
[self.view addSubView:self.topView];
[UIView animateWithDuration:0.5
animations:^{
[self.topView setAlpha:1.0f];
}];
}
In the above method we create a custom UIView and animate it into position. We maintain a pointer to it so we can remove it later (like so:)
- (void)dismissViewButtonTapped:(id)sender
{
[UIView animateWithDuration:0.5
animations:^{
[self.topview setAlpha:0.0f];
}
completion:^(BOOL finished) {
[self.topView removeFromSuperView];
}
}
Its a little more work that using modal views, but it gives you much more flexibility in regards to what you use and how you display it.
Hope this helps:)

UITableView frame height animation glitch

If I attempt to animate the frame height of a tableView (ex: height -= 200), the cells that appear in the last 200px disappear suddenly before the smooth animation of the frame completes.
To make sure that it's nothing else I'm doing, I created a new View-Based application. In the main viewController I create my own tableview with enough pseudo rows to fill the entire screen. And on selection of a row I do a simple height animation.
most relevant code:
- (void)viewDidLoad {
[super viewDidLoad];
self.myTable = [[[UITableView alloc] initWithFrame:CGRectMake(0, 0, 320, 460)] autorelease];
myTable.delegate = self;
myTable.dataSource = self;
[self.view addSubview:myTable];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
CGRect frame = self.myTable.frame;
frame.size.height = 200;
[UIView beginAnimations:nil context:nil];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationDelay:.5f];
[UIView setAnimationDuration:0.5f];
self.myTable.frame = frame;
[UIView commitAnimations];
}
Does anyone know why this is happening, or what a fix/workaround may be?
Any suggests are really appreciated.
TIA!
I'm not sure I had exactly the same problem, but using [UIView setAnimationBeginsFromCurrentState:YES]; solved (parts of) the glitches (my table view slid around crazily when animating a frame height change).
Same problem here as well. This is what I'm doing and the origin animates smoothly, but the size changes immediately... annoying.
[UIView beginAnimations:#"HideTabbar" context:nil];
[UIView setAnimationDuration:.3];
self.tableView.frame = CGRectMake(0.0, 44.0, 320, 366);
[UIView commitAnimations];
UPDATE: Try adding this before the animation:
self.tableView.autoresizingMask = UIViewAutoresizingNone;
For anyone hitting this question & answer in the future, here's how to use #ryyst's answer in UIView's block based animations introduced in iOS 4.
[UIView animateWithDuration:0.3 delay:0.0 options:UIViewAnimationOptionBeginFromCurrentState animations:^{
// change frame etc here
} completion:^(BOOL finished) {
// any clean up here
}];
This is an old question and there are already a couple suggestions for a workaround, but I thought I'd add mine.
I ended up animating the contentInset and scrollIndicatorInsets properties, which provides the illusion that the table itself is being resized.
I have exactly the same problem. I imagine that tableviews have a special behavior on "setFrame:", it seems that the tableview remove the cells that won't be visible with the new frame.
In case of an animation, the cells won't be visible only at the end of the animation, but it seems that tableviews don't care.
If someone have a better theory, I'd be glad to hear it !
Finally found the solution! there is indeed a bug!! don't use variables, when animating the height use [[UIScreen mainScreen] bounds]. Like this:
[UIView animateWithDuration:0.5 animations:^{
tableView.frame=CGRectMake(0, 38, fullScreenRect.size.width, [[UIScreen mainScreen] bounds].size.height-38);
}];
not :
[UIView animateWithDuration:0.5 animations:^{
tableView.frame=CGRectMake(0, 38, fullScreenRect.size.width, fullScreenRect.size.width-38);
}];
and it will work like magic!
I found your question while seeking the proper method to resize a tableView. I think your problem is in your animation you've specified UIView instead of UITableView. I was unable to duplicate your problem using either UIView or UITableView, but I'm using SDK 3.1 and it might be a bug that has been fixed since your post. I'm not sure, but I hope this helps!
It's an old question but this might help someone in the future;
I solved a similar problem by embedding the tableview in a UIView, and resizing the UIView instead of tableview. I set the tableview's height to a large value and also "clip subviews" property on the UIView. I resize the UIView proportional to tableview's contentSize. Its not a good solution but it worked for my purposes.