I was trying to add a pinch gesture zoom-in zoom-out feature to a UITextView and then I decided that adding a pinch gesture which zooms the whole screen, covering the whole view hierarchy is a better and more general solution. But I am confused about how to do it: Should I change the frame sizes of all UIView objects or should I somehow scale them? What is the most correct way to do it?
Put all your views in a UIScrollView and then return the view in this delegate method of UIScrollView
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
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I have a collection view cell which contains an UIScrollview in which all of the content sits. I want to have a gesture that allows users to swipe down when the cell is at 0,0 and then that fades away into the list view of the collection view.
However, I still want the users to be able to scroll down into the rest of the cell content.
Should this be contained in the same gesture? If so, how do I override a scrollview's gesture?
Thanks.
Yea just try implement this method from UIScrollViewDelegate:
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
Get scrollView and calculate gestures and make behaviour. And look other methods for make best visual effect :)
I have a background image that is added to UIScrollView with zoom enabled. I am trying to add additional UIImage's on top of the background image that zoom together with the background image?
The idea is to have a background with multiple playing cards were the user can either see the whole playing field with small playing cards or zoom in the whole background including the playing cards for better views on the playing cards.
Your UIScrollview should contain a single zoomable UIView subview. That subview should contain your background UIImageView and all of the card UIImageViews as it's own subviews (if you add the background image first, it will be layered at the back of the resulting composite view)
The containing UIView that is the immediate subview of your scrollview should be the return value to the UIScrollviewDelegate method
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
You can manage your view hierarchy through a UIView's subviews property, which is an NSArray of views. They are layered in the order of the array, so the first view on the array will be at the back when the views are composited for display.
Well you could use the scrollviewdidzoom delegate method to notify you when the scroll view has been zoomed in and out.
From there you could do a number of things like present new UIImages at a specific zoom level using the scrollView.zoomScale property.
Let me know if this helps.
I have UIViewController with UIScrollView in it.
UIScrollView contains multiple UIViewControllers (something like PageControl Apple example).
Each inner UIViewController in UIScrollView is able to handle the change of UIInterfaceOrientation and to redraw it's view.
But when the UIViewControllers are in UIScrollView the rotations events never reaches inner UIViewControllers.
How can I make those inner UIViewControllers to handle rotation events?
Thanks in advance.
Only a viewController in a viewController structure (like tabbarcontroller or navigationcontroller) gets (and handles) rotation events. If you just added the views of some viewControllers, they won't actually rotate, but they will change their framesize accordingly to the new size of the main view. In general you should use autoresizingMasks on every view. Read about them in the documentation.
But in a scrollView there is probably no autolayouting possible. You could overwrite layoutSubviews: in your main view to handle the layout of all scrollView subviews based on the scrollView frame.
Perhaps you can detect when the device is rotated, then using the transform property apply the necessary rotation programmatically using CGAffineTransformMakeRotation(-M_PI_2), for example...
Is there a way to change the "layer" that UIImageView objects are drawn in? Whenever I add an image view to a view controller it defaults to drawing the most recently added one on top of all the others. So if I decide to add a "background" image it is now a "foreground" image and blocks everything else.
There isn't anything in the IB options or in the UIImageView class reference and I haven't been able to find anything here on SO. It's been a problem for a while and it's weird that I haven't seen anything about it before... I think it might just be my semantics coming from a delphi background.
Anyway, does anyone know about this issue / ICANHAZTEHCODEZ to fix it? Or is this just like the UIScrollView problem and poorly supported by the development environment.
This happens when I try to use the editor to arrange the subviews.
You can bring a SubView to Front or Send it background programmatically using
[self.view bringSubviewToFront:yourImageView];
and
[self.view sendSubviewToBack:yourImageView];
when self.view must be the superview of your imageView
In IB, select a UIControl and from top menu bar select Editor->arrage->send to front or back
When you use UIView's addSubview: method, it will add it to the top of the view stack resulting in what you are seeing.
There are numerous other UIView methods you can use to determine the order of subviews. E.g.:
- (void)insertSubview:(UIView *)view aboveSubview:(UIView *)siblingSubview;
- (void)insertSubview:(UIView *)view atIndex:(NSInteger)index;
- (void)sendSubviewToBack:(UIView *)view;
- (void)bringSubviewToFront:(UIView *)view;
I have two UIScrollViews that I move images between. The user can drag and forth between the scroll views. I am trying to animate the movement of the image from one scroll view to another. In -touchesMoved (handled in my UIViewController which has two custom UIScrollViews that intercept touch and sends to my UIViewController), I am trying to set the "center" of my UIImageView that is being moved. As it is moved, the image gets hidden behind the UIScrollView and not visible. How do I make it appear on top of the UIScrollView? I am able to handle the -touchesEnded properly by animating in the destination scroll view.
I am also confused about -convertPoint:fromView: usage in the iPhone Programming Guide (See Chapter 3, Event Handling). If the touch coordinates are in window coordinates, to change my view (UIImageView inside a UIScrollView which is inside a UIView and inside a window) center don't I have to use -convertPoint:toView:, i.e.,
imageView.center = [self.view.window convertPoint:currentTouchPosition toView:imageView];
What am I missing?
You can use the method - (void)bringSubviewToFront:(UIView *)view for making the image view the front most view.
Johan
It depends on how you structured your views. If both scrollviews and the imageview are at the same level, it should work. If the imageview is a subview of one of the scrollviews, you can try bringing the scrollview to the front. That way also the imageview will be drawn over the other scrollview.
Johan
I have a View Controller with two ScrollViews. Images are added as subviews. ScrollViews are already in the front. I tried bringing scrollview to the front and also imageview of the scrollview to the front. But somehow when i drag, the center of the image goes over my other scrollview2 which i also tried sending back. But does not seem to work. Here is what i do, in TouchesMove (inside a ViewController)
view= [[scrollView1 subviews] objectAtIndex:currentImageIndex];
[self.view bringSubviewToFront:scrollView1];
[scrollView1 bringSubviewToFront:view];
[self.view sendSubviewToBack:scrollView2];
scrollView1 and scrollView2 are two scrollviews that are part of the ViewController's view.
Does this make sense ?
thanks
mohan