What do you advise? should I programmatically draw my textfields, labels, images or should I use IB?
Would it make any difference? I have scrolling issues (bit jerky) but not something I cannot live without!
I would use IB to help maintain the app. Jerky performance is usually a result to memory management issues and not specific to IB. IB just does the object creation and sets common properties, so do it in code, or in IB the end result is the creation of objects and setting of properties.
ok. problem solved. you were right and wrong regarding the IB...
to explain myself:
I was loading my cell from a nib file.
The trick and thanks goes to this site: http://iphoneincubator.com/blog/tag/dequeuereusablecellwithidentifier
i forgot to set my cell identifier to the nib file so i was creating the cells every time they were scrolled off the screen!
so tip!
When you load from nib ALWAYS put the right identifier in the "identifier" place!!!
thanks to nolimitsdude who actually pointed to the right way!!
Related
Recently, I encountered a problem with the Interface Builder which I failed to solve. I'm using a UICollectionViewController and whenever I add a Cell it immediately shows a orange rectangle (indicating a auto-layout update). Updating the frame/cell doesn't change anything. The warning associated with the orange marking reads "Expected: height=Y, Actual: height=X" where Y is always exactly X-100. That is: When I set a custom cell height of 193, it says "Expected: height=93". This happens no matter which size I enter.
The problem with this is that I have many difficulties with the subviews and their constraints. For instance, if I add a subview with the constraint to keep the same height as the cell, it will be shown as 93 (the expected height), even though my cell should be 193. Layouting becomes impossible.
I tried adding a new cell, same issue. I tried removing every subview and re-adding them, nothing.
Any ideas are highly welcome.
Thank you very much!
Solution found ! (Xcode 9.2)
The bug seems to only happen when you try to embed the UICollectionViewController in a Container View in the storyboard. The workaround is to remove the segue while you set your constraints, and re-add the segue once your constraints are well set.
I also think that setting UICollectionViewController size as Freeform could be responsible of the bug. If so, try to set constraints before changing the size.
Hope this helps !
I'm not sure if this solved it, but the warning and issue disappeared once I did the following:
Select the CollectionViewController in Interface Builder and set the size to freeform and make the height larger, large enough to show all your template cells. (Plus: maybe refresh the views). That solved the issue for me.
In my case, I have added two collection view cell, withing collection view Controller.Only setting the view controller to free form wont help us. Need to update the size, to get rid of the warning.
updating collection view cell frames, wont help us. Warning will be continuously changing its length.
I tried to work without considering the warning, as I have set my collection view cell size programmatically and it does working as expected.
I think it's just a strange bug
I delete the collectionViewController in SB, then create a new one, the problem disappear
This is a common bug with Interface Builder. I don't know the exact cause, but I believe it's something to do with placing collection views inside arrangement views that do not have an exact size. I've seen it when putting them in scroll views, stack views and container views.
There is a simple fix, although I believe this to be a bug in IB that ought to be corrected by Apple rather than hacking around it. The solution (for me at least - your mileage may vary!) is to place the collection view inside an ordinary UIView and pin its edges to it, then place that parent view in the position that you wanted your collection view with all the constraints it required.
I usually found that there were actually no auto layout issues at run-time, which is why I believe this to be purely an Interface Builder bug.
I've managed to get drag and drop working on my NSCollectionView, but there are some issues with the visual appearance and behaviour. The main issue is that the drop zone / placeholder is the wrong size i.e. it's smaller than the collection view's minItemSize. I've scoured the documentation, but can't see any way to specify this.
The second issue I have is that I'd like the cell image to actually be moved when it's being dragged, rather than just having the semi-transparent copy.
Here's the current behaviour:
And here's the behaviour I'd like to have (as used in Sketch):
Any suggestions would be greatly appreciated. Let me know if any of the code would be useful — I'm not sure which parts would be relevant to solving this. Thanks!
I am just learning Xcode. I did something that caused a view controller to turn black below the navigation bar when you build app.
It looks white in storyboard.
Also, when I pull a label onto the storyboard, it aligns to the left margin and does not show the drag boxes around it.
I may have inadvertently clicked something but when I compared it in attributes and identity inspectors line by line to another project, nothing seems amiss, i.e. everything is the default value.
Has anyone run across this?
There is not code in associated class that would cause this as it is generic i.e. plain vanilla.
Would appreciate any suggestions. Thx.
With that little information i'd say you removed the root view of the controller?
Either way, you say there is no code, so I'd suggest you simply delete that controller and create another one (bottom right, objects, viewcontroller). Since it's empty you're not gonna lose any data or time :)
Then link it to your class in the Identity Inspector and you're good to go as if it was a new one.
I have an NSTabView which has 5 tabs. Each tab contains an NSTableView (which, as default, is nested in NSScrollView). This is all loaded from a xib file with autolayout turned on. I'd like each table to fully occupy it's respective tab. Using autolayout I select each tab and carefully setup the NSScrollView so that it snaps its top, bottom, lead, and trailing edges to superview. After I do this for the 5 tabs, I'll resize the xib to give it a test. When I cycle back through the tabs, some stay snapped to the superview and some do not. There appears to be some sort of order to this but it is beyond what I can explain.
What's really frustrating is that sometime this will run okay, and sometimes it will crash because of unsatifyable constraints. For now I am using springs/struts but I like autolayout and would like to get it working.
I am afraid that it is the nesting of the tables inside scroll views which is causing the issues.
If you lay this out your own nib, you should be able to reproduce it.
I am hopeful that this can be solved by adding NSLayoutConstraints at runtime, if OSX is anything like iOS's autolayout. Using IB you cannot assing constraints to anythign other than super and sibling (no cousins). This can be done at runtime.
I am hoping someone out there has encountered this issue and has a solution.
Why do the constraints in the layout show a fixed constant instead of auto? Could that be it?
You mentioned cousin constraints, I believe you can add in the in IB if you select two views in the document outline on the left hand side and then add a constraint. I'm unable to pick any two views in IB if I'm using the main window but I can do it in the document outline.
Lastly, you mention it will run okay sometimes but not others - and if that's the case it sounds like something else is adding constraints. Instruments should have a template for tracing constraints, if you can reproduce it you may get a clue to what is introducing the incompatible constraint.
In my application i am adding views to a window and i am setting windows size correctly to fit the views.But when i am trying to resize the windows the views in the window the views are not getting fitted depending on the window size one view gets overlapped with the other one and mismatchings. Can any one help me in this isssue by posting some sample how to do it.
i am new to mac development and got strucked up in this issue.
Thanks in advance
NSView has a setAutoresizingMask: method where you can specify how the view should resize, when its parent view changes size.
You can set this in code, but it might be easier to use Interface Builder.