In viewWillAppear I want to adjust some of my views using the following transformation (Monotouch code):
CATransform3D oTransform3D = CATransform3D.Identity;
oTransform3D.m34 = 1.0f / -400;
oTransform3D = oTransform3D.Translate( 110, 0, 0);
oTransform3D = oTransform3D.Rotate( (-70f) * (float)Math.PI / 180f, 0, 1, 0);
However, this causes the view to be rendered far left of the screen.
If I put the very same code in viewDidAppear, it is working.
I have already checked that all views have valid sizes.
Did you ever figure this out? I've run into a similar situation where a 3D transform refuses to behave when applied to an immediate subview of a UIViewController's root view. A workaround for me was to wrap the subview in another container UIView.
Something along these lines:
- (void)viewDidLoad {
[super viewDidLoad];
UIView *container = [[UIView alloc] initWithFrame:CGRectMake(0,0,self.view.frame.size.width,self.view.frame.size.height)];
container.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoResizingFlexibleHeight;
[self.view addSubview:container];
self.myCrazyFlippingSpinningView = [[CrazyFlippingSpinningView alloc] init];
[container addSubview:self.myCrazyFlippingSpinningView];
}
Of course, I'd prefer to not have to do that. It's such a hack. If anyone's encountered this and has a better solution, I'd love to see it.
Thanks!
Not sure I fully understand the question but I am going to take a swag.
CATransform3D has a vanishing point that transforms refer to. The vanishing point is always the x,y center point of whatever view you place the transformed view onto. When I was struggling through the 3D transform issues and getting unexpected results, it was always solved by simply making sure I knew the size and center point of the container view.
You say your code works in ViewDidLoad...does that mean you are adding a transformed view to the base view? like: this.View.AddSubview(yourTransformedView); ??
I mean, I don't think your problem is a matter of ViewWillAppear vs. ViewDidLoad; I am going to guess that if I saw the code where you apply your transform to the views and then add your views to a base view or some other superview, I would be able to quickly tell you what is happening.
Related
I have a UIView. I applied the animation to its CALayer.
[view.layer addAnimation:groupAnimation forKey:name];
I want the final state of the layer to be the state of the UIView after the animation. Let's say I rotated by 45degrees and moved to a new position using the layer; is it possible for my view to be in that state after the animation? Because right now, after the animation, it goes back to the original state of the UIView. I hope to receive some help with this. Thanks.
The thing to understand is that layer animation is just animation; it's merely a kind of temporary "movie" covering the screen. When the animation ends, the "movie" is removed, thus revealing the true situation. It is up to you to match that situation with the final frame of the movie.
UIView animation does this for you, to a great extent. But layer animation leaves it entirely up to you.
Thus, let's say you animate a position change; doing something so that the layer or view actually is where you animated to is completely up to you.
The usual thing is to perform the changes yourself as a separate set of commands. But be careful not to do anything that might trigger implicit layer animation, as this will conflict with the animation you are trying to perform explicitly.
Here's example code (not related to yours, but it does show the general form):
CAAnimationGroup* group = // ...
// ... configure the animation ...
[view.layer addAnimation:group forKey:nil];
// now we are ready to set up the view to look like the final "frame" of the animation
[CATransaction setDisableActions:YES]; // do not trigger implicit animation by mistake
view.layer.position = finalPosition; // assume we have worked this out
When animating a CALayer or using a CAAnimationGroup, the following properties must be set, e.g.:
groupAnimation.removedOnCompletion = NO;
groupAnimation.fillMode = kCAFillModeForwards;
See also: After Animation, View position resets
Also note that it may be helpful to apply animations directly to the view itself, rather than by accessing the view's layer. This is accomplished using animation blocks, which I have found to be very useful.
Block style animations can be customized in many ways, but here's a basic example, which could be invoked within a function when your view needs to animate:
- (void) animateMyView
{
CGRect newViewFrame = CGRectMake(x,y,w,h);
[UIView animateWithDuration:0.5
delay:0
options: (UIViewAnimationOptionCurveLinear )
animations:^{
self.myView = CGAffineTransformMakeRotation (45);
[self.myView setBounds:newViewFrame];
}
completion:NULL];
}
For more information, see Apple's documentation on View Animation.
I'm creating a NSCell subclass that draws some objects directly onto the view (using drawInRect:fromRect:operation:fraction:respectFlipped:hints:) and also draws an NSButton instance simply using NSView's addSubview: selector.
While objects drawn using the first method all draw correclty, I'm having problems with drawing the NSButton correctly. The issue is that my NSButton instances will draw in the right places, but multiple times over.
I've researched this on the internet for a while and some people suggested using a cache, but I'm not sure if this is efficient. (going an array containing buttons using a for loop will definately cause slow scrolling since I display a lot of data...)
How would you do this? Am I barking up the wrong tree?
This is the relevant code:
- (void)drawInteriorWithFrame:(NSRect)cellFrame inView:(NSView *)controlView
{
NSRect _controlRect = cellFrame;
float _Y = cellFrame.origin.y;
NSRect _accessoryRect = NSMakeRect(_controlRect.size.width - 70.0f, _Y + 9.0f, 50.0f, 23.0f);
_switch = [self _choiceSwitch];
[_switch setFrame:_accessoryRect];
[controlView addSubview:_switch];
}
Long story short: Friends don't let friends addSubview, while drawing.
This a fundamental, and not particularly well-explained aspect of managing control interfaces, but is important to come to grips with.
Let your controllers dictate the "order" of subviews, and you can sleep tight knowing that that button shouldn't get overtly mucked about (which is NOT the case if it's getting jostled around inside your custom drawing routines).
It's easy to get trapped in this alley, cause, like, hey, I added an NSImageView in my initWithFrame and everything seems to be okay… But it's just sort of not how you're supposed to do it, I guess… and when you start subclassing NSControl, etc. is when you start to realize why.
Updated: Here's a really good write up on designing custom controls with an equally as great sample project attached - which embodies the kind of code organization that can help avoid this type of issue. For example.. you'll notice in the controller class how he's keeping each button seperate, unique, and independent of other views' business…
for (int butts = 0; butts < 3; butts++) {
NSRect buttFrame = NSMakeRect(0, butts * 10, 69, 10);
ExampleButt *butt = [[ExampleButt alloc]initWithFrame:buttFrame];
[mainView addSubview:butt];
}
“Drawing” NSButton by adding its instance into the view hierarchy each time you draw the cell itself is definitely a bad idea. Instead, create an NSButtonCell and configure it up to your taste. Then, in your -[NSCell drawInteriorWithFrame:inView:] use a cell ivar to draw its appearance.
If you want to have a clickable NSButton instance in each cell of the table view, try to avoid a call to addSubview: when possible. Each time you do this, the control view may invalidate its layout and re-draw everything from scratch making some kind of a recursion in your case.
I have no idea why this code isn't working, but hopefully the fix is simple, I hope someone can help.
I have 2 functions, enterFullScreen and exitFullScreen.
In the enterFullScreen method, I set an NSView's frame to the Window's frame, which has a full-screen effect, this is what I want. Within this method I store the old frames so that in the exitFullScreen method I can set them back, but this isn't working. It has no effect whatsoever. The code is as follows:
NSView oldView, oldViewContainer;
- (void) enterFullScreen:(NSView*)newView
{
// Store original views
oldView = newView;
oldViewContainer = _newViewContainer;
// Set new views to fit window
[_newViewContainer setFrame:[_window.contentView frame]];
[newView setFrame:[_window.contentView frame]];
}
- (void) exitFullScreen:(NSView*)newView
{
// Restore old views
[_newViewContainer setFrame:[oldViewContainer frame]];
[newView setFrame:[oldView frame]];
}
The enter fullscreen method works exactly as expected, but for some reason I can't set the 2 Views back to their original size/location.
I don't know if it's because I can't just store the whole view, or if the origin is causing problems?
I've tried every combination, if somebody could help I'd be really grateful.
Thanks in advance.
You don't want to set oldView to newView, that makes them the same view, so when you resize newView to full screen, oldView's frame also is set to full screen. You want to save the old frame, not the view, so:
oldFrame = newView.frame; (to store the original frame)
then when you resize smaller,
[newView setFrame:oldFrame];
I'm working on some drawing code. I have that portion working great.
I want to draw over an image, but I want to still be able to see the detail of the image, the black lines, etc.
What I am working on is making a transparent UIImageView that holds the image.
I'm not sure how to get this set up properly though.
Should this be added above the other UIImageView that I color on or below it?
Here's what I have so far:
- (void)viewDidLoad
{
[super viewDidLoad];
topImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 46, 320, 370)];
[topImageView setImage:[UIImage imageNamed:#"imagesmall.png"]];
topImageView.alpha = 1.0;
topImageView.layer.opacity = 1.0;
topImageView.layer.opaque = NO;
[self.view addSubview:topImageView];
[topImageView release];
}
Thoughts anyone?
Yes, you can draw views over other views. They are drawn in the order that they're added as subviews, unless you reorder them after that.
You may need to set the opaque property for some views (this is distinct from and overrides their layer opacity), and set their backgroundColor to nil. UIImageView seems to be transparent by default, as long as its image is; some other UIView subclasses are not.
So, just what is your overlay going to be? If you just need to display one image over another, what you have here seems to work already. If you need to draw some lines programmatically, you'll need to do this:
Create a subclass of UIView.
Implement its drawRect method to display the content you need.
When you add your custom view on top of the background image, make sure it is not opaque and has no backgroundColor.
A common problem here is to find that your foreground is working, but the background isn't being loaded properly. To make sure the background is there, set the alpha of the foreground view to 0.5. You won't want to do that in production, but it will allow you to verify that both views exist.
This question has been asked before but in a slightly different way and I was unable to get any of the answers to work the way I wanted, so I am hoping somebody with great Core Animation skills can help me out.
I have a set of cards on a table. As the user swipes up or down the set of cards move up and down the table. There are 4 cards visible on the screen at any given time, but only the second card is showing its face. As the user swipes the second card flips back onto its face and the next card (depending on the swipe direction) lands in it's place showing its face.
I have set up my card view class like this:
#interface WLCard : UIView {
UIView *_frontView;
UIView *_backView;
BOOL flipped;
}
And I have tried flipping the card using this piece of code:
- (void) flipCard {
[self.flipTimer invalidate];
if (flipped){
return;
}
id animationsBlock = ^{
self.backView.alpha = 1.0f;
self.frontView.alpha = 0.0f;
[self bringSubviewToFront:self.frontView];
flipped = YES;
CALayer *layer = self.layer;
CATransform3D rotationAndPerspectiveTransform = CATransform3DIdentity;
rotationAndPerspectiveTransform.m34 = 1.0 / 500;
rotationAndPerspectiveTransform = CATransform3DRotate(rotationAndPerspectiveTransform, M_PI, 1.0f, 0.0f, 0.0f);
layer.transform = rotationAndPerspectiveTransform;
};
[UIView animateWithDuration:0.25
delay:0.0
options: UIViewAnimationCurveEaseInOut
animations:animationsBlock
completion:nil];
}
This code works but it has the following problems with it that I can't seem to figure out:
Only half of the card across the x-axis is animated.
Once flipped, the face of the card is upside down and mirrored.
Once I've flipped the card I cannot get the animation to ever run again. In other words, I can run the animation block as many times as I want, but only the first time will animate. The subsequent times I try to animate lead to just a fade in and out between the subviews.
Also, bear in mind that I need to be able to interact with the face of the card. i.e. it has buttons on it.
If anybody has run into these issues it would be great to see your solutions. Even better would be to add a perspective transform to the animation to give it that extra bit of realism.
This turned out to be way simpler than I thought and I didn't have to use any CoreAnimation libraries to achieve the effect. Thanks to #Aaron Hayman for the clue. I used transitionWithView:duration:options:animations:completion
My implementation inside the container view:
[UIView transitionWithView:self
duration:0.2
options:UIViewAnimationOptionTransitionFlipFromBottom
animations: ^{
[self.backView removeFromSuperview];
[self addSubview:self.frontView];
}
completion:NULL];
The trick was the UIViewAnimationOptionTransitionFlipFromBottom option. Incidentally, Apple has this exact bit of code in their documentation. You can also add other animations to the block like resizing and moving.
Ok, this won't be a complete solution but I'll point out some things that might be helpful. I'm not a Core-Animation guru but I have done a few 3D rotations in my program.
First, there is no 'back' to a view. So if you rotate something by M_PI (180 degrees) you're going to be looking at that view as though from the back (which is why it's upside down/mirrored).
I'm not sure what you mean by:
Only half of the card across the x-axis is animated.
But, it it might help to consider your anchor point (the point at which the rotation occurs). It's usually in the center, but often you need it to be otherwise. Note that anchor points are expressed as a proportion (percentage / 100)...so the values are 0 - 1.0f. You only need to set it once (unless you need it to change). Here's how you access the anchor point:
layer.anchorPoint = CGPointMake(0.5f, 0.5f) //This is center
The reason the animation only ever runs once is because transforms are absolute, not cumulative. Consider that you're always starting with the identity transform and then modifying that, and it'll make sense...but basically, no animation occurs because there's nothing to animate the second time (the view is already in the state you're requesting it to be in).
If you're animating from one view to another (and you can't use [UIView transitionWithView:duration:options:animations:completion:];) you'l have to use a two-stage animation. In the first stage of the animation, for the 'card' that is being flipped to backside, you'll rotate the view-to-disappear 'up/down/whatever' to M_PI_2 (at which point it will be 'gone', or not visible, because of it's rotation). And in the second stage, you're rotate the backside-of-view-to-disappear to 0 (which should be the identity transform...aka, the view's normal state). In addition, you'll have to do the exact opposite for the 'card' that is appearing (to frontside). You can do this by implementing another [UIView animateWithDuration:...] in the completion block of the first one. I'll warn you though, doing this can get a little bit complicated. Especially since you're wanting views to have a 'backside', which will basically require animating 4 views (the view-to-disappear, the view-to-appear, backside-of-view-to-disappear, and the backside-of-view-to-appear). Finally, in the completion block of the second animation you can do some cleanup (reset view that are rotated and make their alpha 0.0f, etc...).
I know this is complicated, so you might want read some tutorial on Core-Animation.
#Aaron has some good info that you should read.
The simplest solution is to use a CATransformLayer that will allow you to place other CALayer's inside and maintain their 3D hierarchy.
For example to create a "Card" that has a front and back you could do something like this:
CATransformLayer *cardContainer = [CATransformLayer layer];
cardContainer.frame = // some frame;
CALayer *cardFront = [CALayer layer];
cardFront.frame = cardContainer.bounds;
cardFront.zPosition = 2; // Higher than the zPosition of the back of the card
cardFront.contents = (id)[UIImage imageNamed:#"cardFront"].CGImage;
[cardContainer addSublayer:cardFront];
CALayer *cardBack = [CALayer layer];
cardBack.frame = cardContainer.bounds;
cardBack.zPosition = 1;
cardBack.contents = (id)[UIImage imageNamed:#"cardBack"].CGImage; // You may need to mirror this image
[cardContainer addSublayer:cardBack];
With this you can now apply your transform to cardContainer and have a flipping card.
#Paul.s
I followed your approach with card container but when i applt the rotation animation on card container only one half of the first card rotates around itself and finally the whole view appears.Each time one side is missing in the animation
Based on Paul.s this is updated for Swift 3 and will flip a card diagonally:
func createLayers(){
transformationLayer = CATransformLayer(layer: CALayer())
transformationLayer.frame = CGRect(x: 15, y: 100, width: view.frame.width - 30, height: view.frame.width - 30)
let black = CALayer()
black.zPosition = 2
black.frame = transformationLayer.bounds
black.backgroundColor = UIColor.black.cgColor
transformationLayer.addSublayer(black)
let blue = CALayer()
blue.frame = transformationLayer.bounds
blue.zPosition = 1
blue.backgroundColor = UIColor.blue.cgColor
transformationLayer.addSublayer(blue)
let tgr = UITapGestureRecognizer(target: self, action: #selector(recTap))
view.addGestureRecognizer(tgr)
view.layer.addSublayer(transformationLayer)
}
Animate a full 360 but since the layers have different zPositions the different 'sides' of the layers will show
func recTap(){
let animation = CABasicAnimation(keyPath: "transform")
animation.delegate = self
animation.duration = 2.0
animation.fillMode = kCAFillModeForwards
animation.isRemovedOnCompletion = false
animation.toValue = NSValue(caTransform3D: CATransform3DMakeRotation(CGFloat(Float.pi), 1, -1, 0))
transformationLayer.add(animation, forKey: "arbitrarykey")
}