I have a view controller and have a few objects that I have some simply animations hooked up to.
[UIView animateWithDuration:0.25
delay: 10.1
options: UIViewAnimationOptionCurveEaseIn
animations:^{
addNameViewConstraint.constant = 10;
addNameView.alpha = 1.0;
[self.view layoutIfNeeded]; // move
}
completion:nil];
[UIView animateWithDuration:0.25
delay: 0.15
options: UIViewAnimationOptionCurveEaseIn
animations:^{
addEmailViewConstraint.constant = 10;
addEmailView.alpha = 1.0;
[self.view layoutIfNeeded]; // move
}
completion:nil];
When I was using the push segue the animation works fine. But when I switched to using a modal segue the animation stopped working. I increased the delay in the first one to 10.2 seconds thinking that maybe it was animating before I got to see it. I am calling this animation in the viewWillAppear method. Again works if I'm doing a push segue.. but not for modal. Any ideas?
I am calling this animation in the viewWillAppear method
This is a common mistake. viewWillAppear: is too soon to start the animation. The view has not yet appeared so there is nothing to animate. Move the animateWithDuration:... code to viewDidAppear: and all will be well.
This is, however, as you say in your comment, insufficiently satisfying. What you are after is that the modal transition should be happening and your extra animations within the new view should already be happening as the modal view is in the process of appearing. Instead, with viewDidAppear:, the modal view finishes appearing, it settles into place, and then your other animations start, which is not as cool.
One solution might be to move the animations again, this time to viewWillLayoutSubviews. This is trickier because this method gets called a lot. You will need to use a BOOL instance variable as a flag to ensure that your animations run only once. Thus, this should work (I tried it and it seemed fine):
-(void)viewWillLayoutSubviews {
if (!self->didLayout) {
self->didLayout = YES;
[UIView animateWithDuration:0.25 animations:^{
// mess with constraint constants here
[self.subv layoutIfNeeded];
}];
}
}
Related
I am slowly animating a UIImageView from one image to another. Like so:
[UIView transitionWithView:self.backgroundView duration:30 options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
self.backgroundView.image = endImage;
} completion:nil];
Is there some way to terminate the animation partway through, in response to an event?
A certain Tim Oliver tells me this is how you do it:
[self.backgroundView.layer removeAllAnimations];
You can also retrieve the frame the animation ended on using self.layer.presentationLayer.frame, if you need to freeze the view in the partially animated state.
I'm new to programming Xcode/objectiveC and this questions seems like it should be painfully obvious but I cannot find an answer; how do i move to a different view controller after an animation completes (without a button or other user interaction). in other words go back to the "home" screen automatically after it finishes. right now the image that is animated just stops moving and stays there after the animation finishes and i'm stuck in that viewController.
i'm guessing the coding should have something to do with the selector but i'm not sure
[UIView setAnimationDidStopSelector:#selector ???];
thanks!
UIView's animateWithDuration has a completion block in which you can put code that is executed when the animation is completed.
[UIView animateWithDuration:duration
animations:^{
animations
}
completion:^(BOOL success) {
[self performSegueWithIdentifier:#"YOUR_SEGUE"];
}];
I am not much into iOS animation. What I am trying to achieve is a simple message view that slide vertical from bottom of screen to a given y, then after few instants the UIView rollback in vertical to go off screen.
[UIView animateWithDuration:0.5f
animations:^{
self.messageView.frame=CGRectMake(x, y -80, width, height);
}
completion:^(BOOL finished){
if (finished) {
[UIView animateWithDuration:0.5f delay:2.0f options:UIViewAnimationOptionCurveLinear
animations:^{
self.messageView.frame=CGRectMake(x, y + 80, width, height);
}
completion:^(BOOL finished){
// do something...
}
];
}
} ];
This is working fine, but I am having a problem using this mechanism in a iOS UITabBar application: when I change tab, the animation stop, I can infact see that "finished" completion is "false". Therefore the second block is not called, and the message view stays on.
Here are the questions:
my first concern is to understand if the code I have written is correct, regarding the nested animations.
I could solve by ignoring 'finished' and execute code anyway, but I don't feel it is a good idea
within the last completion block, I have put some programming logic, basically I am restoring few UIButtons state, and some other little UI change. At this point I don't know if it is a good idea, it seems not, but how can let the UI knows that the message view has disappeared. NSNotification and KVO seems a bad idea when fast responsive UI change are involved.
You can stop all animations for a layer by sending the layer a removeAllAnimations message.
[sel.view removeAllAnimations];
This is how I switch from one UIView to another UIView: self.view = MyView;
How would I fade out a view to my MySecondView?
You can use UIView's build in transition code to cross dissolve between them.
[UIView transitionFromView:self.view toView:MySecondView duration:0.25 options:UIViewAnimationOptionTransitionCrossDissolve completion:^(BOOL finished) {
// What to do when its finished.
}];
You can also use the regular animation options with something like this. I haven't tested this code as I'm not in front of Xcode but I use it all the time for labels and things without default animations.
[UIView animateWithDuration:0.25 animations:^{
[self.view setAlpha:0.0];
self.view = mySecondView;
[self.view setAlpha:1.0];
}];
Please note that it's not a good idea to do things like self.view = MyView to change screens. By the time you get to a few screens, your viewController will be filled with spaghetti code. You should consider presenting new view controllers that manage their views. One way you can do fade is as follows:
Fade the current view to black (with animation)
In the view controller that you are going to push use viewWillAppear to fade the view to black as well
Push/Present the view controller without animations.
Now use the viewDidAppear method of the newly presented view controller to fade in the view (with animation).
Same code as in a previous question, but a different issue.
I've created a custom animation to add a view controller to a UINavigationController. This code scales a view to 80% the original size, then flips it, then scales it back up to its original size:
[UIView animateWithDuration:scaleDuration delay:0 options:UIViewAnimationOptionCurveEaseIn animations:^{
// Scale the controllers' views down.
self.view.transform = CGAffineTransformScale(self.view.transform, 0.8, 0.8);
} completion:^(BOOL finished) {
// Transition to the new view and push on the new view controller.
[UIView transitionWithView:self.view duration:1 options:UIViewAnimationOptionCurveLinear | UIViewAnimationOptionTransitionFlipFromLeft animations:^{
[self pushViewController:viewController animated:NO];
} completion:^(BOOL finished) {
[UIView animateWithDuration:scaleDuration delay:0 options:UIViewAnimationOptionCurveLinear animations:
^{
// Scale back to the original size.
self.view.transform = CGAffineTransformScale(self.view.transform, 1.25, 1.25);
} completion:nil];
}];
}];
The issue is that, when the animation completes, the new view is displayed very nicely, except that it is drawn under the task bar. That is, it draws in at screen origin 0,0, rather than 0,20. The "Status Bar" option is set in IB (to "Black"), and, naturally, this does not happen if I use a standard UINavigationController push animation, only my custom one. If I rotate the device after the animation, the redraw on rotation moves it to the proper place. But how do I get it to do that in the first place?
As an added wrinkle, it does not draw under the task bar if I move the pushViewController:animated: call a line down to the completion: block (though then the view appears to flip to itself and then suddenly show the new view, of course).
I found the only work around so far is hide the navigationbar and then show it.
after you set your transform, add following 2 lines:
[self setNavigationBarHidden:YES];
[self setNavigationBarHidden:NO];
It's ugly but works, I am also looking for a better solution.
note: layoutsubview, setNeedsLayout won't work.