First time using a UICollectionView if you can believe it, and I'm wondering how to get the cells to basically fill out the maximum allowed space.
The the view for the SE, it's filling out... mostly OK and how I want it. Sure, I'd like the blocks to go all the way to the bottom of the black area (colors are temporary of course), but it's close enough.
On the iPhone X, and other larger screened phones of course, it maintains the "minimum" spacing, but what I'd like it to do is to auto adjust the spacing so that they fill out the area. Top two blocks at the top and bottom two blocks at the the bottom, with equally distributed space in between.
Oddly enough, I was able to achieve this quite easily when I did it manually with each of them in the regular view. I started trying to use a UICollectionView because it started to really look ugly once it rotated into landscape mode. Here's a shot of how those items were setup using the more manual method.
Any suggestions? Seems like something that'd be an easy switch... but I seem to have hit a wall and am stumped. Am I missing something so blatantly obvious here, or what?!?
Oh, and I've also toyed with using:
-(CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section
To set the spacing of the line items programmatically, but that wasn't without problems either. In there, I was checking for the screen height, dividing by the count of items and using a variation of that as the spacing.
That seemed to "work" at first.
But in my testing, that function only fires when the view is very first loaded, and then only when it goes into landscape mode. When it comes out and goes back to portrait, it doesn't re-fire and recalculate. Thus... keeping the (now new) landscape spacing.
You need to create UICollectionViewFlowLayout and compute size of the items programmatically.
Or override UICollectionViewDelegateFlowLayout item size.
https://developer.apple.com/documentation/uikit/uicollectionviewdelegateflowlayout/1617708-collectionview
Related
I made a profile area where it has some buttons and information about the person like followers and their posts:
But I was advised to make using multiple horizontal/vertical stackviews as it (a) is easier to manage for different sized screens and (b) is easier to constrain as a whole in the view. I made the exact copy and all the items (like the textViews or images) are taking up so much more space than they need to which makes the whole thing so much bigger, then when I try and space stuff out or in, everything just either goes on top of one another or it gets bigger. Could someone explain this behaviour? Here's the same thing just using the stackviews:
As you can see in the picture, the '#username' textview is taking up so much space bother horizontally and vertically and I cannot even change that in the inspector as it just defaults back. The stack view hasn't got any constraints on it at all at the moment so no constraints are acting on it either.
I've been doing iOS for a while now, but when it comes to dynamically hiding / showing elements, I'm a bit lost.
Coming from Android, I'm used to being able to simply set views to visibility gone, but this doesn't exist on iOS.
So let's say I have the following scenario:
Basically I want to have a table, but the table should not fill the entire view controller. Instead it should leave place for optionally either a button, a multiline label, or possibly both at the bottom (if visible, these should be fixed, not scroll).
One way to solve this would be to use auto layout and modify constraints, like adding a zero height constraint. But that would make iOS kill one of the other constraints, which would make it hard to change it again. For the label, I wouldn't always want to have a height constraint, because it could be multiline, and should take the size it needs.
Maybe it's easier to skip autolayout here and modify frames instead, I don't know.
My question is: What approach would be best here?
Is there some other way of doing this I haven't thought of, or do I have to try to do what I described above?
I'm not primarily looking for code (code can be ok), but I'm more interested in a description of how it can be done.
I'd like to support iOS 7.
This problem had a variety of solutions, and opinion based, but I'm facing such questions a lot, when I don't know what to choose and what would be the "right thing".
So, I my opinion, the best solution here is using autolayout, you need to set height of label manually, but you have a few methods for this, at least you can play with it and if you don't succeed ask question about it. Using frames, you'll face same problem of calculating height, right? But with auto layout, you only need to set height, vertical space to 0, when you need to hide message.
You can also use constrains with priority lower 1000, and remove completely constraints from message (button, label) if you don't need it at all anymore.
For example, taking your layout image, you can make UIView with subviews: button, label. Top constraint connect to the UITableView, other constraints to the sides.Label and button will calculate the view's height. The only question here is label height.
So in ios assuming that the background of both these objects is opaque only the front most view in the Heirarchy will be visible and interactable, An easy solution would be to change the different frames of these two things you need and make sure they are in the back of your view heirachy, and when you need them to appear use view.bringSubviewToFront(mySubview) and view.pushSubviewToBack(mySubview) to make it disappear again. View obviously would be referring to main view of your view controller.
I have issue with autolayout.
I have three different views (could be n views as well). When I pin first one to top of super view and connect one next to the other everything seems fine. But if I want to change height of first one the other two does not follow (they stay on the same position). What I find weird about this is that if I connect only two views this works perfectly.
To have better understanding what I am trying to achieve I made simple, example solution with three views:
http://i.stack.imgur.com/cMwiB.png
So, when I set height of green view to 0 ( can be any other number as well ) and only red view is connected, this works fine, red will move as it should. Blue one is not connected and it remains where it is:
Here is screenshot when I connect blue to red:
What I tried to do:
connect blue one to green as well ( not working)
connect blue only to green ( not working )
"boxing": have boxes with views at the time ( ugly, hard to manage, not working in all cases)
What I would like to know:
what makes this happen? Can I change this kind of behavior?
What is the best practice to have flexible length for height (Besides UITableView)
Thanks in advance.
Ok, I think you're falling into the same trap I did, when I investigated autolayout some time ago. It's tricky to explain, but I'll do my best. When you work with autolayouts, you need to forget completely about setting a view's frame at all. And that, my friend, includes changing size and positioning. When you use autolayout, you define some constraints, some "rules", that the view tries to respect when rendering the screen, so the more specific the rules are, the less random will be the behavior of the view. I mean, if you just define the spacing between views, you're implying that the height of the views doesn't matter, so it's possible that some views grow or shrink when the re-layout is called (that is, if you don't specify a constraint for size. You probably want to always specify the size of some views in every layout...)
By the way, you're allowed to violate the constraints by manually changing the frame of an element AFTER a re-layout is called, but when the re-layout method is called again, the constraints will be forced so the size and positioning of the views will change. Quick tip: an easy way to force the re-layout method is to change orientation (command+left / command+right in the simulator).
So after saying that, I have to say that the layout you provided is completely working as intended, at least to me. When you change orientations the constraints you specified are ALWAYS being respected. If you want, you can try to apply some frame-setting in the viewDidAppear method, because this one is called AFTER the autolayout (and thus, you're able to violate the constraints temporally). After doing this, your view will be broken but once you change orientation the constraints should be respected again. Make sure it's that way.
From here I can only wish you luck ;) Oh, and refer to the documentation, it was a life saver to me when I looked at this half a year ago. https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/AutolayoutPG/Introduction/Introduction.html It might seem a classic, but it's a pretty nice doc.
EDIT: one last thing. I have the impression that constraints are not designed to be dynamic. You define them once, and they're there always. Their main purpose is to ensure that subviews are rendered as intended in every screen resolution without fail, so if I were to make an application with moving views, I would leave them outside of the autolayout, or avoid using it at all. Just a personal impression though :)
I'm trying to use Auto Layout for a custom Table View Cell in my app.
I can't seem to get the constraints quite right.
I layed the labels out in the custom Table View Cell, but the labels are still getting cut off. Any ideas?
Thanks! Will post anything else needed. Tried to show needed info in picture below:
Debugging in Xcode. Somehow what shows in Simulator looks different than in Xcode debug.
Here's the width of my TableView shown:
UPDATE:
The problem here was related to what user matt said in the accepted answer, but I wanted to make the Q&A a bit clearer now that I have it figured out for anyone else that comes across this.
In his initial comment, he mentioned the Xcode View debugging, which was great and I was able to dig into a little bit more. Its called the Assistant Editor: Device Preview, where you are able to see the layout and layers of what is onscreen to see if maybe you have labels overlapping or going offscreen based on the device it is running on. If you want to check multiple device sized, just hit the plus icon in the lower left hand corner of this picture.
This helped me find overlapping layers and sizing issues with the TableView. I was able to see how it looked on each device size.
What also helps here sometimes to use the Pin menu. Sometimes the labels can run off screen because it doesn't know where the constraints of the cell are based on the device size. So your label can run offscreen if the label is based off of a landscape layout but the device is an iPhone 5 and is in Portrait for example. This is the Pin menu:
Hope that makes sense and gives some more color to the problem. Let me know if you have any questions at all, thanks for the help everyone!
The problem is that you are using auto layout but you have not done anything about sizing the table view. The table view here is not your view controller's view; it is a subview. Your view controller's view is automatically sized to the size of the device / window, but its subviews are not automatically resized. So you are ending up with the table view much too wide for the device; the whole table is sticking off into space on the right side.
Use a trailing space from the right side of your labels to the edge of their superview, and set it to greater than instead of equals with a value of ~ 5
Review the constraints of your tableview with the View. Draw cell border, label border and tableview border with different colors to know which elements do not display correctly.
Ex:
#import <QuartzCore/QuartzCore.h>
...
cell.layer.border.width = 1;
cell.layer.border.color = [UIColor blackColor].CGColor;
The thing that worked for me to solve views being clipped was to uncheck "Constrain to margins" in Auto Layout.
I'm using a nav bar orchestrated set of tableviewcontrollers to display a hierarchy of data. The bottom level of data is displayed in a custom tableviewcell, which has its content described in a xib, and results in a required cell height larger than the default. I posted another question on how to programmatically extract the resulting cell height, but no usable answers, so I now implement heightForRowAtIndexpath to return a hardcoded value that is the height in the xib attributes panel. But, when the table is displayed with more rows than can fit in the normal display size (480h,320w), the bottom row is chopped off as expected, but I can't scroll it to see the rest of the row. I've searched rather extensively, but nothing has helped. I poked at various attributes (tableview sizes, scrollingEnabled, etc.) but they all seem as expected values (e.g., scrollingEnabled is true). One post suggested that no scrolling would occur unless the contentSize was larger then the frame, so I looked at those values, and it sounds promising, in that my frame size is a typical 460h x 320w, but, my contentSize is 0 x 0! Further searching (e.g., "setting contentSize" or "contentSize is 0") didn't clear anything up. I thought contentSize was computed for free from the table row count and their heights, so how could I be getting 0? Even going back to allowing a default row height by not implementing heightForRowAtIndexpath still resulted in a 0 contentSize. Some searches suggest turning off autoLayout for the custom table cell, but still the same. So, what might be going awry? Thanks for any thoughts or guidance.
Update: Sorry, I confess! I had originally been developing on a mac mini with a regular USB mouse, where scrolling in the simulator was left button down and drag. I recently switched to an iMac with the magic mouse. I'm now so used to just dragging my finger on the mouse to scroll code, web pages, etc., that I didn't think to try clicking and holding the left mouse "button", and then dragging the mouse. When I did, everything worked as expected. I had really thought things were hopeless when any similar variables/values in the app on the mini were equal to those on the iMac, but it was just me getting tricked by fancy technology. Sorry for the distraction.
set your tableView's frame and your cell's frame correct,and implement
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath in your UITableView to give a right height. If that doesn't work try set your tableView.autoresizingMask to UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
which can help you with the size of the tableview
I had a similar problem. My tableView would't scroll when the content exceeded the tableViews frame.
The problem for me was that I had "Use Autolayout" checked but no constrains on the tableView. Adding vertical and horizontal space constrains on the tableView fixed my problem