I have a big problem concerning the resizing of a derived UIView with a UIScrollView as subview.
In the layoutSubviews message I set the frame of the UIScrollView subview. the UIScrollView contains a UIImageView with a big image which can be moved/pinched and so on. The initial contenSize of the UIScrollView is the initial image size.
So far, so good. Moving and pinching of the image works well. Now I have to change the UIView frame (in my app to maximize the UIView). im doing that in a animation block (beginAnimations/commitAnimations). So I set the new frame (which will update the width & height) an then I call [myView layoutIfNeeded] to force the UIScrollView to update its frame in the layoutSubviews message of my view.
The UIView animates correct to its new frame and if the contentOffset of the UIScrollView is currently x 0, y 0 the UIScrollView frame will be updated properly. but here's my problem: if the contentOffset of the UIScrollView is bigger than x 0, y 0 the UIScrollView will "slide in" from upper left to its final position.
I want that the UIScrollView resizes its frame properly with the parents frame and aligns the content (in my case the UIImageView) right. But how could I achieve that?
after hours of web research i found the solution for this problem:
[UIView setAnimationBeginsFromCurrentState: YES];
this will animate all layers from the current state.
Related
I have few fields and UIView inside the UIScrollView (Fields on top and UIView at the bottom. UIScrollview size is larger than the screen size).
What i am thinking!
UIView should be autoresize according to its super view (UIScrollView) but it is resizing according to UIViewController view..
[UIView setAnimationBeginsFromCurrentState: YES];
this will animate all layers from the current state.
I have a view that has a table view on the top, and a scroll view below the table view.
When I press the resize bar button item, I want to hide the table view and maximize the scroll view. I got the scroll view and table view to animate correctly, but I am trying to resize the UITextView inside the scroll view to take advantage of the extra screen space.
Whenever I calculate the resize, the UITextView goes to the top left corner of the screen, and I'm not sure why. I am not even modifying the X and Y, just the height.
CGRect newDesFrame = descriptionTextView.bounds;
newDesFrame.size.height = newDesFrame.size.height + tableViewFrame.size.height;
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:.5];
self.scrollView.frame = scrollFrame;
self.descriptionTextView.frame = newDesFrame;
[UIView commitAnimations];
I am not sure why this happens. Does the descriptionTextView.bounds get messed up since it's in a UIView inside a UIScrollView? It seemed that, when I do a NSLog of the X and Y of the scroll view, it's 0,0. It's weird since it's not at 0,0 in the superview, or in the view. How do I fix this?
descriptionTextView is most likely jumping to the top left because you are, in fact, changing the origin (x and y). You are starting with:
CGRect newDesFrame = descriptionTextView.bounds;
Getting the bounds of that text view will give you a CGRect with an origin of 0,0, as 'bounds' gives you the view's rectangle in its own, local coordinate space.
Try this instead:
CGRect newDesFrame = descriptionTextView.frame;
This will give you the view's rectangle in its superview's coordinate space, including the actual origin.
It happens because you are doing
self.descriptionTextView.frame=newDesFrame ( which is Bounds property, not frame!! To read about differences Link)
Solution:
self.descriptionTextView.bounds=newDesFrame
I have five UIView on a UIScrollView. All of them with the same width. Each view has other subviews that resize its height according to the content assigned, thus making the parent UIView and the UIScrollView resizable as well. I am trying to keep the 5 UIView separated from each other at a certain "Padding" distance even after resizing. What I do right now is set the position of the origin.y and the height of each UIView when layoutSubviews is called. Is there an easier way to do this?
I have tried to set their position on creation like: CGRectMake(0, aboveView.frame.origin.y + aboveView.frame.size.height + Padding, width, 0) and setting its autoresizingMask to UIViewAutoresizingMaskTopMargin. Hoping that when I call sizeToFit on the main UIView, all the UView will set their positions relative to the view above them.
Overriding layoutSubviews is the right way to do this. UIKit doesn't have any built-in layout management that can do it for you.
However, you might not realize that UIScrollView sends itself layoutSubviews each time it scrolls - on every frame of the scrolling. That may be a lot more often than you need! You don't want to do a lot of work in a UIScrollView's layoutSubviews if you can avoid it.
To avoid doing extra layout, I suggest you set up your view hierarchy like this:
UIScrollView
ContainerView with layoutSubviews method
content view 1
content view 2
content view 3
content view 4
content view 5
Use a standard UIScrollView. Give it one subview, which is a custom UIView subclass (I called it ContainerView in my example). The ContainerView has your five content views as its subviews.
When you assign new content to one of your five content views, send sizeToFit to that content view. If the view's size changes, UIKit should automatically send layoutSubviews to its superview - the ContainerView. The ContainerView's layoutSubviews method adjusts the position of its subviews to maintain the padding between them, and then sets the contentSize of its parent - the UIScrollView.
- (void)layoutSubviews {
CGRect myFrame = CGRectZero;
for (UIView *subview in self.subviews) {
CGRect frame = subview.frame;
if (myFrame.size.height > 0) {
frame.origin.y = myBounds.size.height + Padding;
subview.frame = frame;
}
myFrame = CGRectUnion(myFrame, frame);
}
self.frame = myFrame;
UIScrollView *scrollView = self.superview;
scrollView.contentSize = myFrame.size;
}
This way, you don't do any extra work just because the scroll view scrolled. You only lay out your content views when the content actually changes.
I have a UIView that contains another UIView. The outer UIView draws a border around the inner UIView via drawRect. (The border is too complicated to be drawn via CALayer properties.)
At present, when I animate the resizing of the outer UIView, its drawRect method is called once at the beginning of the animation and the result is stretched or shrunk. This does not look good.
I am looking for a way to either redraw the content at every step of the animation, or find a way to achieve the same visual effect. (The result should be similar to the resizing of a stretchable UIImage.)
You should change view's content type to:
your_view.contentMode = UIViewContentModeRedraw;
And it will redraw each time its frame changes.
I ended up adding subviews with autoresizing masks that kept them positioned correctly during the animation.
You need to send a [UIView setNeedsToDisplay] to the view for every time the frame size is changed, you could try overriding the setFrame: method like
- (void)setFrame:(CGRect)r
{
[super setFrame:r];
[self setNeedsToDisplay];
}
I want to make a View with three subviews stacked on top of each other with the middle subview scrollable with the others fixed.
How can I achieve this programmatically? I have tried
to set the contentsize of the root view to the size of the scrollable view but that makes all the views scroll.
-set the contentsize of the middle subview without setting any property for the root view but that makes all the views unscrollable.
Please help. I am new to iOS.
Thanks in advance
You can use the scrollViewDidScroll: delegate callback on the UIScrollView to adjust your view's position. In the callback, get the contentOffset of the scrollview and use that to set your fixed view's position.
For example, if you want your fixed view to always remain 100 px from the top of the scrollview, set its initial frame to (0, 100, width, height), and then in the callback set the frame to (0, contentOffset.y + 100, width, height).
The result is that the subview will appear fixed at a given height.
If your UIScrollView has a superview (i.e. a container view), you can add your 'fixed' view as a subview of the superview instead of the UIScrollView. You'll only have to calculate your frame coordinates once.
You can do it moving sub view from UIScrollView to super view of scrollview like:
Place/set your button over scroll view (not inside scroll view) as shown here in this snapshot. And also set button constraints (position) with respect to super view of your scrollview.
Here is ref. snapshot of hierarchy of position of each view over each-other.