I'm new to Cocoa and I'm programming a custom InspectorView.
A parent view (InspectorView) contains several subviews (InspectorCategories).
If I uncollapse a category (subview) I have to resize/relayout my parents view?
I found out that this is not possible through autoresize masks - Is this correct?
I tried it with resizeSubviewsWithOldSize in my parents view but this gets not called while resizing the subview.
How can I achieve this behavior?
There are two parts to accomplish what I think you want:
(a) In the parent view, override the sizeThatFits: method so that it computes a new size that fits around the resized subview.
(b) In the subview, override the setFrame: method and after the frame size is changed, it calls [self.superview sizeToFit] to resize the superview, perhaps like this:
-(void)setFrame:(CGRect)newFrame
{
[super setFrame:newFrame];
[self.superview sizeToFit];
}
No, it is not possible to do through autoresizing masks. Autoresizing mask defines how the view is resized when its superview changes bounds.
The subview should let its superview know what size it needs, for example through a delegate call. The superview then should resize itself and the subview.
Related
I have a UIScrollView that of course contains information. Based on conditions I make changes to the height of the scrollview as such:
CGRect scrollFrame = self.scrollView.frame;
scrollFrame.size.height = scrollFrame.size.height + adMobBannerView.frame.size.height;
self.scrollView.frame = scrollFrame;
I then add the scrollview back:
[self.view addSubview:self.scrollView];
All of this works as it should. However, should I first be removing the scrollview from the superview before adding it again? While again what I am doing works, I am wondering if I am just layering scrollviews on top of scrollviews unnecessarily?
You don't have to add UIScrollView as subview after you change its height (if it is currently added as subview).
When you try to add view A as a subview of view B and view A has superview it would be removed from its superview so you don't have to call removeFromSuperview method yourself.
From Apple Documentation:
Views can have only one superview. If view already has a superview and that view is not the receiver, this method removes the previous superview before making the receiver its new superview.
I have a NSView wrapped in a NSScrollView using the IB. In the initialization function of the view (class is NoteView) containing the NSScrollView, I attempt to add subviews to the NSView as follows:
// Initialize custom view with width 802 and height 130, call it initialSubview
// Set initialSubview's frame origin to (20.0, 580.0). documentView of scrollView
// is size (842.0, 740.0)
// Let innerView be the documentView of the scrollView (I have an IBOutlet attaching
// the scrollView's document view to innerView)
[innerView addSubview:initialSubview];
When I do this, nothing shows up. Likewise, trying this:
[[[scrollView] documentView] addSubview:initialSubview];
doesn't work either. However, if I added it to the contentView:
[[[scrollView] contentView] addSubview:initialSubview];
The subview shows up fine. Any ideas?
As an addendum, if I add something like an NSButton to the documentView in the IB, nothing
shows up as well.
I figured out the issue. It seems NSScrollView and Auto-layout fight themselves.
The solution is to remove whatever you're documentView is (in my case innerView)
from their superview, setTranslatesAutoresizingMaskToConstraints to no, and re-add the view.
The code looks something like this:
[innerView removeFromSuperView];
[innerView setTranslatesAutoresizingMaskIntoConstraints:NO];
[scrollView setDocumentView:innerView];
Then you have to set any constraints you'd like manually
I am pretty sure contentView is the correct place to add it. You may also need to update the content size.
Adding views to a NSScrollView from IB adds the view to the NSScrollView's contentView(NSClipView).
According to your setup you have
NoteView is clip view(contentView) of the NSScrollView.
document view of the scroll view is innerview.
inner view(documentView)'s subview which is initialSubView is added from
-initWithFrame: of contentView.
In an NSScrollView a contentView represents the 'clipped' representation of the documentView.
Having the documentView initialized in init of the contentView is why nothing happens.
Do This
Add NoteView from -awakeFromNib or similar entry point as documentView of the NSScrollView.
Add initialSubView as a subview of NoteView.
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 have a UIImageView in a UIScrollView in another UIScrollView (based on Apple's
PhotoScroller sample code). When the UIScrollView calls back to its controller to dismiss itself, it calls this method:
- (void)dismiss {
[scrollView removeFromSuperview];
ImageScrollView *isv = [self currentImageScrollView];
UIImage *image = isv.imageView;
image.frame = [self.view convertRect:image.frame fromView:isv];
[self.view insertSubview:image belowSubview:captionView];
[(NSObject *)delegate performSelector:#selector(scrollViewDidClose:)
withObject:self
afterDelay:2.0];
}
Now here's the weird part: the image view jumps to a different position right after this method executes, but before the scollViewDidClose method gets called on the delegate. If the image is larger than its new super view, it jumps so that its left edge is aligned with the left edge of its super view. If it's smaller than its new super view, it jumps to the very center of the view. There is no animation to this change.
So my question is, how do I prevent it from doing that? I've tweaked both the super view (self.view) class and the image view class to see what methods might be called. Neither the frame nor the center is set on the image view after this method is called, and while the layoutSubviews method is called on the super view, that is not what jumps the image to the center or left side of the superview. I've also tried turning off autoResizesSubviews in the super view, and setting the autoresizingMask of the image view to UIViewAutoresizingNone, with no change in behavior.
So where is this happening, and why? And more importantly, how do I make it stop?
I've been beating my head on this for days. Any pointers or guidance would be greatly appreciated.
ImageScrollView is the one centering your UIImageView. Set a breakpoint in ImageScrollView layoutSubviews and you'll see how your UIImageView is being centered.
You're taking ImageScrollView's internal imageView and placing it into another view. That's not going to work because ImageScrollView still retains ownership of that UIImageView instance and is still managing its layout.
You'll either need to copy the image into another UIImageView instance, or you'll need to change ImageScrollView to allow it to relinquish ownership of its imageView.
You're not setting up the frame of the 'image' view when you insert it as a subview. You probably want to do that explicitly if you want the view to appear at a particular position in the scroll view.