Is it possible to set height of super view relying on summarized height and padding between its child elements using auto layout?
Basically I'm trying to fill subviews with text from remote server, views are changing height dynamically, but their superview (or container view in other words) is static.
See -intrinsicContentSize and -invalidateIntrinsicContentSize. I believe this alone will get you there in simple cases. As I understand it, other things (including superviews with constrained distance from edges of a subview) will be moved to accommodate a view that claims a minimum size that would break those other constraints (keeping your view visible, for example).
I'd love it if others would chime in to validate/invalidate/correct me here. I'm still wrapping my own head around the many details specific to Autolayout in practice.
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Im making a custom keyboard, and wanting a label and a textField centered in the space left over the keyboard, I figured the proper way would be to incorporate them in a UIstackView, and then centering the stack. However, i'm having som issues with the stack resizing my textField, causing whatever text i enter to be clipped.
I tried adding compressionresistance and a number of different solutions, but its clear to me that im missing some information about how UIStackViews work. Usually i make them work, but the whole resizing part I dont understand.
The first two screens are without a stack, adding them as subview to the viewcontrollers view, and the second screenshot shows the stackView resizing my textfield everytime the keyboard is resigned.
How can i stop the stackview from resizing its contained views?
It seems UIStackView is inherently a auto layout component, and when it adds your arranged subviews, it automatically positions them using constraints.
Since the UIStackView is adding constraints of its own, and the best way I found to stop it, was to simply explicitly set the subviews constraits:
textField.widthAnchor.constraint(equalToConstant: 300).isActive = true
Apple doesnt like dynamic StackViews: "In general, you should not use dynamic stack views to simply implement a scratch-built table view clone." Read the
Apple Documentation on UIStackView for details.
I have a page enabled scrollview on an iPad. On the first page, I have a child scrollview that scrolls horizontally through image buttons. The buttons scroll the outer scroll view to the correct page. Its basically like a table of contents that jumps to the correct page.
My end goal is to be able to categorize the buttons seen in the child scroll view. So there would be a segmented control that changes what buttons you can see. So maybe one category would be ALL, and another category would be A-M, and another would be N-Z for example.
My question is, should I use a uiscrollview or a uitableview?
Right now I use a scrollview and it is really easy to get the buttons in. I could implement the different categories kind of gimmicky by having all of the buttons in the scrollview and then just showing or hiding the buttons accordingly. I feel that it'd be bad memory usage though.
For a uiscrollview i was looking at using EasyTableView, butI'm not 100% sure if this is compatible with what i want to do or if it'd even be better.
Any ideas for what the best way to implement this is? Specifically, I'm not sure of the best way to change the buttons when I change categories.
Thanks!
Use a tableview when you are dealing with data that is best expressed as sections and rows.
I think for your situation I'd have a UIView subclass that can display the images you need for a given category. Stick that on the outer scrollview as needed. You can keep memory low by only keeping the currently visible view and the ones on either side on the scrollview. When you scroll to a new location you can recreate the view needed for that page, and the ones surrounding it. Then you release the ones that are far away and let the system reclaim their memory if needed.
For a simple example lets say I have a UITextView with a Button underneath it. These two controls are siblings both embedded in a parent UIView.
I now change the text within the UITextView and resize it accordingly. Is there a way to make the button automatically move to have the same relative distance to the bottom of the UITextView? This may seem trivial for this case, but I will have a longer hierarchy with multiple UITextViews that change and it would be nice not to have to calculate the height of every object manually.
One way to approach this would be with a table view: if you place each of your text views within its own table view cell, the table view will automatically calculate its total height from individual calls to its delegate’s -tableView:heightForRowAtIndexPath: method and lay itself out accordingly. Whenever the height of one of your text views needs to change, you can call -reloadData on the table view to make it lay itself out again. A disadvantage of this approach is that it’s really difficult to animate the height changes; if that’s essential to the effect you’re going for, I’m afraid you’re stuck with doing the entire layout manually.
Try the autoresizingMask property of UIView.
I have a loadView call that basically places one view at the top (like a header) and one at the bottom (like a footer). It's possible via a passed in parameter to not have a header or a footer, to hide them later, or to resize the view. I have all this working, but it's very susceptible to breaking because the views can go in various places of various sizes and all must be manually set to the correct size or they will not use up all the space. I want one in between the two of them that automatically resizes to fill whatever space is not taken by the others.
loadView doesn't seem to be able to obtain the size of its parent's frame (or where it's being fit in, exactly), nor do I see an obvious way to just put the center view at a certain position and have its width and height automatically adapted.
Any ideas?
If I'm not explaining myself well enough and you know Java Swing, think BorderLayout with a BorderLayout.NORTH, BorderLayout.SOUTH, and BorderLayout.CENTER component.
loadView isn't a good place for this. You really want to use viewWillAppear instead. Setting autoresizeMask to have fixed borders should do what you want without having to worry about calculating layout, and it's best to do this all in IB rather than doing manual layout all the time.
I have a view (UIScrollView), which loads some data, and displays various things from it in various subviews. So I have approx 10 subviews (UIImageView, UILabel) and I need to place them programatically considering their unpredictable contents (i.e. different height/width for the UILabels depending on the text property).
From what I've read, there is no layout framework for Cocoa-touch.
What is the best way to do this?
From what I can tell, I should put the contents in the views, then start calculating coordinates based on their frames after calling their sizeToFit methods.
This approach is very error-prone. Is there really no other way?
You are right, there are no automatic layout managers. Subclassing UIScrollView and overriding layoutSubviews is probably the right way to implement your custom algorithm. You can then call setNeedsLayout to do the layout.
Layout in Cocoa is typically done with auto-resizing (using autoresizingMask). You start with your view at some hard-coded initial size, say 200x200; place your subviews onto this view and set the autoresizing flags accordingly. This view is then free to be resized to its actual size, as determined by its parent view/window. The process is the same whether you use Interface Builder or whether you do it programmatically.
If you need a vertical stack of views you can use a table view.
If you want more complicated layout you need to implement it yourself, by overriding layoutSubviews.
I'm not aware of any automatic layout managers or the like.
So, I think you'll have to calculate the desired positions and sizes and update the frames of your subviews manually.
EDIT: I found this question where Brad Larson points to an example of a custom layout manager. HTH
You can use Interface Builder to create a view and then drag and drop elements into it.