I was in an (probably false) assumption that enabling the right margin indicator in xib is equivalent to using UIViewAutoresizingFlexibleLeftMargin
inside code and so on.
So, I used to think according to this snapshot:
Later today I had to cross check, and stumbled upon this thread.
And also the apple documentation, entitled with the section with title - "Handling Layout Changes Automatically Using Autoresizing Rules" in this link: https://developer.apple.com/library/content/documentation/WindowsViews/Conceptual/ViewPG_iPhoneOS/CreatingViews/CreatingViews.html
So I now have a renewed concept in my mind as to how setting autoresizing masks programmatically would be equivalent to xib settings:
Scenario 1:
Setting only (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight)
is equivalent to:
In XIB?
Scenario 2:
Setting (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin)
in code is equivalent to:
In XIB?
Are my 2 renewed scenarios correct? Am I right now in my understanding?
Yes, Interface Builder has it "reversed" in a sense (or UIView, depending on how you look at it). Your cited "scenarios" are correct.
Enabling the vertical/horizontal arrow (called spring) inside the box will make the height/width flexible. But enabling an outside line (called strut) will make that side inflexible/ non-flexible.
Enabling the outer left line (left strut) is not equivalent to enabling
UIViewAutoresizingFlexibleRightMargin
. Instead,UIViewAutoresizingFlexibleRightMargin
= on if right strut disabled, off if right strut enabled.It is quite confusing at first, but if you see closely, there is a difference in the springs and struts. I don't know why Apple did this, but for me, there were some cases where it was easier to use. And using opposite properties in code is even more confusing.
Swift 4 use this
Objective-C
Yes, you have cited things correctly. Also, I agree that it feels a bit backwards, so for that reason I appreciate your post.
You might like using a preprocessor Macro
UIViewAutoresizingFlexibleMargins
when making a UIView's margin flexible in every direction. I put this in the precompiled header file so it gets included everywhere.Using
UIViewAutoresizingFlexibleMargins
will make a UI Element stay centered since it will NOT be hugging any one side. To make the element grow / shrink with its parent, set theUIViewAutoresizingFlexibleWidth
andUIViewAutoresizingFlexibleHeight
respectively.I like using
UIViewAutoresizingFlexibleMargins
because I can later reference it like:instead of
All to often I see these margins OR'ed together on one line like the example above. Just hard to read.