UIScrollView has ambiguous scrollable content but it has no content - uiscrollview

Why does this scroll view have ambiguous scrollable content, when it doesn't have any content?

Presumably, you are laying this out with the intention of adding subviews (with proper constraints) to the scroll view at run-time.
But, Storyboard / Interface Builder has no idea what your code is going to do in the future.
You can either leave it as is and ignore the warning,
or
Tell Storyboard to stop warning you about it by selecting the scroll view and then selecting Ambiguity: Never Verify in the size inspector pane:
or
Add some content, such as a UIView that you will use to hold the UI elements you plan to add at run-time.

Related

NSToolbarItem and Auto Layout

I have a window with a programmatically created toolbar, which is populated with an NSToolbarItem that has a custom view defined in a xib file. If I check "Translate Masks into Contraints" for the view, then it doesn't resize itself correctly, so its content gets squashed even though I set its compression resistance priority to 750. If I uncheck that on the other hand, then I get a "Detected missing constraints" error at runtime. Also, the content of my view then resizes itself correctly, but it ends up clipped like so:
So it looks like the toolbar sticks my view into a container view and, in order to get the correct behaviour, I should set up layout constraints that allow my view to position itself correctly. However, I don't see how to access that container view... Any idea what I am doing wrong?
I am probably missing something obvious since one would think that this is a very standard setup, but Google didn't come up with anything.
Answering my own question, I opened a support request with Apple, the outcome of which is that this is now being treated as a bug by Apple.
In case anyone else runs into this, a good workaround is to create an intermediate view which contains the toolbar view as a subview with constraints #"H:|[toolbarView]" and #"V:|[toolbarView]", has translatesAutoresizingMaskIntoConstraints=YES and to use this view as the toolbar item. It then suffices to listen for size change notifications of toolbarView and to adjust the size of its superview accordingly.

How to call NSScrollView autoscroll-method programmatically

I have simple chat application with text messages view-based NSTableView as you can see at the picture below.
Each message contains NSTextView instance having height to fit all the text.
All I need is to start NSScrollView (which NSTableView-instance is enclosed by) autoscrolling while the user selecting text dragging mouse far enough. Unfortunately, autoscrolling doesn't appear. In case of dragging somewhere outside of the text views all succeed.
I tried to call autoscroll:-method directly by simply push NSEvent-instance from NSTextView-subclass "mouse dragged"-event (like in example from this article):
- (void)mouseDragged:(NSEvent *)event
{
[self.scrollView autoscroll:event];
}
As I've overrode all the mouse events and implemented all the text selecting, this method often invokes. But the autoscrolling doesn't seem to work.
UPDATE
I figured out that before calling -autoscroll:-method there must be -mouseDown: of the same object. But it breaks my text selecting mechanism. The point even not in being first responder, there must be nothing but the mouseDown:-method.
Normally, a text view is within a scroll view of its own. Even if that's big enough to show all of the text without scrolling, it's still there. A call of -autoscroll: on anything within that scroll view (possibly including that scroll view itself?) will just try to scroll that scroll view, not the scroll view that contains the table view.
Try calling -autoscroll: on a view higher up in the hierarchy. Either self.scrollView.superview, the table cell view, or the table view.
Note, though, that the table view's scroll view will keep scrolling even after the cell view containing the text view is fully on-screen. In fact, it may keep scrolling it so far that it's off the screen in the other direction. Basically, it doesn't know that you're trying to select within the text view so it doesn't know to stop when the selection extends all the way to the edge of the text view.
Another approach might be to try to use a "bare" text view with no enclosing scroll view. I don't think IB will let you do that, so you'd have to do it programmatically. Bare text views don't play well with auto layout, though.

UIScrollview scroll not working

UIScrollview scroll is not working when i tested application in device (iPhone 5), But scroll is working properly in iPhone 5/5s/6/6 Plus simulator. I am developing application using Xcode 6 and UIStoryboard with AutoLayout.
I set the top, bottom, left and right constraints of UIScrollview with relative to Superview. And i also set the constraints of every UIControl which is in the UIScrollview.
Has any one have solution regarding this issue?
Please see below screenshot for reference.
It's probably easiest to have the scroll view contain a single view, which then contains all of your scrollable content. That single view should be anchored to all 4 sides of the scroll view, and if it's only meant to scroll vertically (which is what your screenshot makes it look like), then set the content view to be the same width as the parent of the scroll view.
To make sure an UIScrollView scroll, you have to check
Size
Your content View is bigger than your Scroll View. If you want it to be scrolled vertically, make sure its higher; horizontally, wider.
Constraints
Make sure your Scroll View is pinned to its super view, Top, Bottom, Leading, Trailing.
Make sure your Content view of Scroll View DOES NOT have CenterY constraint set to Scroll View, cause that'd make content view stuck with Scroll View and it'd never be able to scroll. (That happens to me the last time I was stuck)
Interface Builder settings
Make sure the check in Interface Builder under Scroll View is checked:
Scrolling section, Scrolling Enabled.

Xcode tableview hidden behind navigation bar

Can anyone please tell me how to fix the following issue.
I am building an iPhone app using Storyboard. I have a Navigation Controller as root view and off that a view controller. On this I have a few buttons that when clicked takes you to a table view controller. All fine and well, but when I link the buttons to their respective table views, the top navigation bar obscures the top cell in the table view controller.
Does anyone know why this is happening and how I can fix it?
Also it seems to have thrown off my layouts from the view controller from which they inherit.
See attached image for a better explanation perhaps.
I believe this is the intended behavior when using the translucent navigation bar. It's semi transparent specifically so that you can see items pass behind it (e.g. a table scrolling). If you don't want this, changing the navigation bar's style to opaque should solve the problem.
Since I wanted to keep the translucence, I just added a UIView between the navigation controller and the prototype cell (width of the view, height 60). That way the first cell in the table starts beneath the navigation bar but I can still see the scrolling underneath.
This is a bug/feature in IB when you use a translucent navigation bar, the content view runs under the navigation bar. For non transparent bars the content view begins after the bar. If your content view is a UIScrollView (UITableView is a descendent of UIScrollView) the content will be automatically scrolled so as to not be hidden under the navigation bar. So the problem only exist in IB when you run the app everything should be ok.
You just need go to the Navigation Controller properties, then Simulated Metrics, and change the Top Bar to be a Transluscent Navigation Bar WITH PROMPT. And that should be it. No need for that extra UIView

How to stop interface builder resetting user constraints on UIScrollView?

I'm having trouble getting a UIScrollView to respect the constraints I put in interface builder.
All I need to be able to do is set the content size of the scroll view from within IB.
The UIScrollView contains a single UIView.
Constraints on the UIScrollView:
Constraints on the UIView:
I've read through the documentation, and so have set things up as follows:
the UIScrollView has constraints pinning it to its superview, thus defining its size from outside
the UIView (content) has a fixed size (through width and height constraints)
the UIView is pinned to the UIScrollView, thus defining the content size
However, IB won't let me enter these constraints. If I change the 'Bottom Space' constraint between the view and the scroll view, shown in the image as -2196, to 0 (thus pinning the lower edge of the scroll view), then the 'Top Space' constraint resets to a non-zero value. The same happens in reverse. (I haven't yet tried in Xcode 5, which has a far saner approach to invalid constraints in that it doesn't just throw yours away when it feels like it.)
What am I missing?
Every time I've tried to do something even mildly sophisticated with constraints in Xcode 4's Interface Builder, I've eventually given up and either written the constraints in code or switched back to springs'n'struts and layoutSubviews (usually after crashing Xcode a few times).
That said, there is another approach to laying out a scroll view with content in IB. Just make the scroll view as big as its content size, and rely on the view controller (or some containing view controller) to resize the scroll view (or its superview) and let the constraints shrink down the scroll view's frame at runtime. The window's root view controller will always set its view's frame to the screen size, regardless of its size in the nib or storyboard, and that resizing flows down the view hierarchy.
I described this approach in more detail in this answer.
If your scroll view's content size is really supposed to be 2196 points tall, this probably won't work so well. I don't have anything better to suggest in that case.

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