I have a UIViewController which has multiple subviews. Each subview is a UIView subclass, and I want to switch between views by tapping the toolbar buttons. I did this by using the animation blocks:
Example:
[UIView animateWithDuration:0.5
delay:0.0
options:UIViewAnimationOptionTransitionFlipFromRight
animations:^{
[StoreView removeFromSuperview];
[self.view addSubview:HomeView];
}
completion:NULL];
Everything is working fine actually. The problem is the transition is not really smooth. For example, the HomeView has five buttons scattered (as part of the design), and whenever I switch from one view to HomeView, these buttons will come from a corner and rearrange itself after the transition, which is not exactly beautiful to look at.
So how will I make these buttons stay in place?
When doing animations with complex subviews you can sometimes get undesirable results as you are experiencing. Not only can some oddities appear, but they are sometimes costly depending on the complexity of the view structure. One suggestion I would make is instead of animating the complex views themselves, you could render the views to a graphics context and animate the resulting image in a UIImageView, using sleight-of-hand to make it appear that you are animating the view hierarchy. In this effect, you avoid doing what amounts to a complex transform on the HomeView and StoreView and instead do simple flip with UIImageView instances. Consider the following example code:
UIImageView *storeImage = // pointer to the image rendered to a graphics context
UIImageView *homeImage = // pointer to the image rendered to a graphics context
[self.view addSubview:storeImage];
[storeView removeFromSuperview];
[UIView animateWithDuration:0.5
delay:0.0
options:UIViewAnimationOptionTransitionFlipFromRight
animations:^{
[storeImage removeFromSuperview];
[self.view addSubview:homeImage];
}
completion:^(BOOL finished) {
[self.view addSubview:homeView];
[homeImage removeFromSuperview];
}];
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 have two IBOutlet variables connected to two instances of UIView in Interface Builder, called blankView and fadedBGView in my ViewController.
How can I set up this code so that the blankView instance will fade into fadedBGView, using the UIViewAnimationOptionTransitionCrossDissolve transition, and the two UIViews can simultaneously transform (move) from their current position (they have equal positions) to 0,0?
What's happening is the fade occurs, and then the fadedBGView view abruptly moves to 0,0.
In other words, I'd like to have the first UIView fade into the second, while simultaneously moving up the screen.
Hopefully this is clear enough to answer.
Best...SL
[UIView transitionFromView:blankView
toView:fadedBGView
duration:1.0
options:UIViewAnimationOptionTransitionCrossDissolve
completion:^(BOOL finished) {
[blankView removeFromSuperview];
}];
[UIView commitAnimations];
CGRect frame = fadedBGView.frame;
frame.origin.x = 0;
frame.origin.y = 0;
[UIView animateWithDuration:1.0 animations:^{
NSLog(#"UIView Transition/Move Called");
fadedBGView.frame = frame;
}];
iOS 4 and newer provides block-based animations, which your code is already using:
+[UIView animateWithDuration:animations:];
+[UIView animateWithDuration:animations:completion:];
Within the animation block, you can set multiple destination values. See Apple's UIView documentation for a reference to the animatable properties. So within one block, you can modify frames, and alpha (transparency) values of views. I'm not sure how the cross dissolve animation works, but if it's simply one view going from 0 to 1, and another view going from 1 to 0, that's easy to implement.
Instead of
UIViewAnimationOptionTransitionCrossDissolve
use
UIViewAnimationOptionTransitionCrossDissolve | UIViewAnimationOptionAllowAnimatedContent
UIViewAnimationOptionAllowAnimatedContent option allows additional animations during transition. Make sure your fadedBGView has correct starting frame.
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.
I'm looking for a way to implement consecutive animations using nested animation blocks.
Somewhat complicated by happening inside a UIScrollView, the size of three UIImageViews (there are many images, and as I scroll through them I constantly swapping out the images in the UIImageViews).
When a scroll is finished, I want to switch out the image in the (visible) middle UIImageView, three times, then back to the original view. I'm trying it thus:
- (void) doAnimation {
// get the animation frames, along with the current image
NSString *swap1 = #"first.png";
NSString *swap2 = #"second.png";
UIImage *original = currentPage.image;
UIViewAnimationOptions myOptions = UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionAllowUserInteraction;
[UIView animateWithDuration:2.0 delay:2.0 options:myOptions
animations:^{ [currentPage setImage:[UIImage imageNamed:swap1]]; }
completion:^(BOOL finished) {
[UIView animateWithDuration:2.0 delay:2.0 options:myOptions
animations:^{ [currentPage setImage:[UIImage imageNamed:swap2]]; }
completion:^(BOOL finished) {
[UIView animateWithDuration:2.0 delay:2.0 options:myOptions
animations:^{ [currentPage setImage:[UIImage imageNamed:swap1]]; }
completion:^(BOOL finished) {
[currentPage setImage:original]; }]; }]; }];
}
When I run this, there is no duration, no delay, it all happens at once, almost too fast for the eye to see. Could this be because "currentPage" is a UIImageView? (Similar to this question?)
There's no delay because UIImageView.image isn't an animateable property. As such, the UIView animation machinery will have no animations to set up and will just call your completion block immediately.
What sort of animation did you expect? You can attach a CATransition object to the underlying layer to get a simple cross-fade, Just use [imageView.layer addAnimation:[CATransition animation] forKey:nil] to get the crossfade with the default values (you can customize the timing by modifying properties of the CATransition before attaching it to the layer). To achieve the subsequent animations, you can either use the delegate property of CAAnimation (CATransition's superclass) to learn when it's done and fire your second one, or you could just use -performSelector:withObject:afterDelay: to start your next animation step after a user-defined delay. The delegate method is going to be more accurate with regards to timing, but the performSelector method is a bit easier to write. Sadly, CAAnimation doesn't support a completion block.
Another approach for you to transition from one image view to another is by using the block animation function transitionFromView:toView:duration:options:completion as discussed in "Creating Animated Transitions Between Views". You would do this instead of animateWithDuration to change images.