I have a custom UIView which I named UIWheel that I am rotating upon TouchDown. This UIWheel has many UIViews which I would like to rotate at the opposite direction (so that they remain appearing upright even after rotation) .
How do I code to tell it to get all of the UIViews in the UIWheel and in TouchDown rotate in the opposite direction?
Using the subviews property, iterate over each subview and rotate it exactly the way you rotate the outer view, but in the opposite direction.
As another option, you can move the part which you do want to rotate into its own subview, and just rotate that subview. It's a little counter-intuitive to rotate every object, then rotate a large number of them back into position.
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I have an app where I have a rectangle that the user can rotate and pan using their fingers. I'd simply like to know what the frame is of this rotated view so I can find out if it intersects another rectangular UIView (can't use the frame property because it gets invalidated when the UIView gets transformed). What's the easiest way to accomplish this?
Every UIView has a property frame which is of type CGRect.
You can access it using view.frame.
After the transform is applied you can use the bounds and center property on the view to get the orientation. It may take a little bit of calculation but i hope you can get to it easily.
Refer to this image from an answer to this question.
I've learned that the best way to get graceful rotation is to set the auto rotation mask on the view that you want resize or move. This works fine if you're using SDK views like UILabel, but if you have your own custom view that uses the drawRect method it doesn't rotate as gracefully. In fact the only thing that happens is that it stretches whatever you drew in drawRect.
I've tried redrawing both before and after the rotation, but it doesn't give me that smooth rotation.
I looked at a UITextField auto rotating (flexible width) in slow motion and it follows the edge perfectly during the rotation. That is what I want my view to do, so how do I do that? My views jump to the right position either before or after the rotation.
The following line will make your UIView stretch the middle pixel only. If this is not your desired behavior I suggest you read the documentation for contentStretch to learn how to manipulate the values of the CGRect.
[self setContentStretch:CGRectMake(0.5, 0.5, 0.0, 0.0)];
I would guess that the UITextField you're looking at has at least three subviews, one displaying the left cap of the field's border, one displaying the right cap, and one displaying the middle, with autoresizing masks of "flexible right margin", "flexible left margin", and "flexible width", respectively. If you set up your custom view something like that, and make sure its autoresizesSubviews property is set to YES, then you should get the same smooth resize that the text field does.
In my iPhone app, I have a view (let's call it RectangleView) within the content view that I'd like to scale, along with all its subviews, when the iPhone is rotated. So, when the phone is rotated from landscape to portrait mode, I'd like RectangleView (and all its subviews) to keep their original shape and position relative to each other, but just get smaller. I am using autoresizing on it and all its subviews in Interface Builder to try and do this.
Now here's the problem. When the phone is rotated, all of RectangleView's subviews scale and move relative to the entire content view, not relative their parent view (which is RectangleView). This is a problem because the content view is now a different shape (portrait) than it was before (landscape), and so all the elements on the screen are in the wrong places, when they should just be scaled down within RectangleView. And I am confused because some of these elements even move out of RectangleView, which I didn't even know was possible since they are supposed to be contained within RectangleView.
Can anyone explain what might be happening here, and how I can just scale RectangleView and all its subviews to retain their original shape and positions, but just on a smaller scale? Thanks in advance!
Are you sure that they are moving out of the RectangleView, and it isn't that the RectangleView is resizing and filling the content area? Also, I'm not sure if it makes a difference, but I found that I needed to call [view setNeedsDisplay] after rotation to make my custom view work properly.
I'm making an app where one of the objects needs to appear not to move or rotate during AutoRotation, but everything else needs to rotate and be repositioned. The way I did this is by manually rotating the object, and moving it into the same position, relative to the device, that it had prior to rotation. The problem is that it looks funny, appearing to rotate into the same position it had before.
If I suppress the animation effects during rotation, it would appear that the object never moved, and everything else just snapped into place, which is what I want. I haven't been able to find anything in the documentation that tells me how to do this though. How do I do this?
When it comes to UIViewController rotation there are two ways you can set up so you get a chance to rotate and move your own views.
In the one-step process, in your UIViewController-derived class provide an implementation of willAnimateRotationToInterfaceOrientation. It gets called and you can kick off your object rotation so while the system is rotating everything else your object is getting counter-rotated so it looks like it's staying put. You'll want to calculate how much to counter-rotate and in which direction based on current interface orientation vs. new orientation.
The other way is to get notified to do custom rotation in two steps. For example, in the first half you can shrink the object down, move it, and rotate it part way then in the second half finish the rotation as you scale back up to normal size. It's a pretty clever way to make the rotation animation look smoother to the eye.
For the two-step process, you need to define two methods. willAnimateFirstHalfOfRotationToInterfaceOrientation gets called for the first half of the rotation (i.e. up to 45 degrees for a 90 degree rotation and at 90 degrees for an upside down flip). Once past that point the second half is called via willAnimateSecondHalfOfRotationFromInterfaceOrientation.
If your object has a 1:1 aspect ratio (i.e square or round) and in the middle of the view then the one-step process will probably work fine. But if it's a non-square object and has to move position (for example if it's at position 40, 60 in portrait but moves to 20, 100 in landscape) and maybe even needs a bit of scaling to look better then you may want to try the two-step process and see if it looks smoother.
If your object is inside its own individual UIView then it's pretty easy to schedule the rotations through UIView animations. Just create a transform through CGAffineTransformMakeRotation, then inside a pair of UIView beginAnimations/commitAnimations blocks set the transform property of the view to this value. You can tweak the timing through setAnimationDuration.
EDIT: Based on the comments, I'm adding some code to show how you could attach the view to the top-level window instead of to the view controller. Your object would then reside in this view instead of the one managed by controller (which is getting rotated). You still need to over-ride the UIViewController rotate methods, but instead of rotating an object under control of the view controller you would trigger a counter-rotation in the object on the top-level.
To add a view to the top-level window:
YourAppDelegate* windowDelegate = ((YourAppDelegate*) [UIApplication sharedApplication].delegate);
[windowDelegate.window addSubview:yourView];
Keep a reference to yourView somewhere you can get to, then in the UIViewController's willAnimateRotationToInterfaceOrientation counter-rotate yourView, i.e. calculate how much to rotate the view in reverse to where you're going--if the phone is turning 90-degrees clockwise, you'll want to rotate the view back 90 degrees counter-clockwise, etc. Then use UIView animations on yourView.
If you don't want rotation animations, overload -shouldAutorotateToInterfaceOrientation: in your UIViewController and return NO. You can then observe UIDeviceOrientationDidChangeNotification to receive manual orientation change notifications.
This may work:
Listen for willRotateToInterfaceOrientation
[UIView setAnimationsEnabled:NO];
Listen for UIDeviceOrientationDidChangeNotification
[UIView setAnimationsEnabled:YES];
Untested, but I know that does work for some cases.
I'm well aware that there are only two available UIView transitions, UIViewAnimationTransitionFlipFromLeft and UIViewAnimationTransitionFlipFromRight. I'm wondering if there is anyway that I can implement / emulate a UIViewAnimationTransitionFlipFromTop or UIViewAnimationTransitionFlipFromBottom.
The only way I can think to do this is by flipping the x axis with the y axis, but I've not seen any information about how to do this. Just setting the coordinates of each axis won't fix the issue as the x-axis till remains the x-axis.
Does anyone have any ideas how this can be accomplished?
You can do this by applying a CATransform3D to your main view's CALayer, with your secondary view's CALayer behind it. In this response, I point to a Mac implementation of this animation by Mike Lee. You should be able to reuse a significant portion of that code to recreate this effect on the iPhone.
Guess you'll have to use a UIView animation block with a 3D rotation transform of 90 degrees, have the Core Animation delegate call you when that's done, swap the view with the new one (3D rotated on the other side) and chain with the last 90 degrees for the new view...
Although its not exactly what you want, there are two built-in animations that you didn't mention: UIViewAnimationTransitionCurlDown and UIViewAnimationTransitionCurlUp.
CurlUp looks like someone is peeling the view from the bottom up to the top, and CurlDown looks like the view is being unrolled down on top of the screen from top to bottom. You should at least give them a look, as they are easy to use.