I have two buttons that I want to be kept the same size, but the problem is that they have two different parent views. Autolayout seems to be ignoring the "equal size" constraint in this scenario. Constraining buttons with the same parent view works just fine.
I've created a very simple example that depicts what I am seeing:
As you can see from the above, buttons Two and Three are both set to have the same size constraint as button One. The only difference is that button Three is contained within another NSView. There are no width constraints that are linking button Three and its containing view.
However, when I run and resize the window, it looks like:
It doesn't matter whether I use the Interface Builder layout, or do it in code using the -[NSLayoutConstraint constraintWithItem:attribute:relatedBy:toItem:attribute:multiplier:constant:] method.
What am I missing? Is this not supported by Autolayout? Thanks a lot.
Edited: Added screenshot to indicate button Three's constraints.
This should work OK. I set up an example project to do the same thing. I have three buttons with equal width constraints between button one and button two. Then the same between button two and button three. Button one has a trailing edge constraint relative to it's parent view.
Note that between the second and third button, Interface Builder didn't let me do this in the main window. Instead, I had to do it using the document list on the left.
The result can be seen below:
Here's the link to the project:
https://github.com/MaxMacleod/ThreeButtonConstraintTest1
Couple of caveats. First, this is an iOS rather than an OS X project (I'm an iOS guy!). However the principles should be the same. Secondly, this doesn't pinpoint the exact reason why your project isn't working. However, if you can compare what this sample project does against yours, we can figure it out. I'll then update this answer. Better still if you could make your project available, I'd be happy to take a look.
Related
I'm trying to understand how autolayout works under XCode6, but there's a lot of mysterious things that runs away from my mind. Autolayout and constraints philosofy can be very hard to learn, but I realized that life can be easier using these tools...
For your information, I need to build a chat view with a table (the messages) and a view containing a text field (the send message pane) nested in a UIView that is again nested in a UIScrollView, so I can shift up the scroll view as the keyboard appears under the textfield.
I read a lot of tutorials and watched a lot of video until I found the useful tutorial Using UIScrollView with Auto Layout in iOS. There's a Xcode project in Github of what the tutorial explains, too.
In his tutorial, Mike Woelmer tells that
One of the big pain points with the old way of setting up a
UIScrollView was communicating the content size to the scroll view. It
was fairly straightforward to calculate your content size if the
content in the UIScrollView was an image. But it was not as easy if
your scroll view included a mixed bag of buttons, labels, custom
views, and text fields. Lengthy code adjustments were needed to
reflect constant changes in device rotations and phone size
differences.
So Mike explains the way to adapt the UIView, using placeholder and forcing the view inside the scrollview to fits the device's screen, creating in viewDidLoad some NSLayoutConstraint:
The solution is to look outside the scroll view and attach a
constraint to the view controller’s main view. This cannot be done in
interface builder, so we will have to write some code. Interface
builder is still complaining, though, so we have to add a placeholder
width constraint to make it happy.
I tried to use parts of the code of the tutorial for my project, but I cannot get a working view controller for my needs (I always get errors). Which is the best approach to do this? Am I on the right road?
Last but not least, I'm italian, so pardon for my english. If something is not clear enough, please leave me a comment.
Basically you have to set both alignment and size constraints in order for Autolayout to take care of the rest for you. If you don't provide enough information you get warning. If you provide conflicting information you get errors.
You need basically to provide enough information for Autolayout to calculate the UIView frame property (i.e., x-position, y-position, width, height).
For example, by providing the distance constraints from the top, right, bottom, and left edges, Autolayout has enough information to draw that UIView's frame rectangle. But you could also provide just the distance constraints from the top and left edges and then provide a size and height constraint.
You can also configure the key constraints you need and then click 'resolve auto layout issues' and choose 'add missing constraints' though sometimes it doesn't give you what you want. It is better to understand that how Autolayout accomplishes what I described above.
If you mess up, it's usually easier to clear all the constraints and start over. Do it a few times and you'll get the hang of it.
I have a settings screen with a couple of segmented controls on it. All was well until I added a third. Now the new one works, and the top one works, but the one in the middle doesn't...
It used to work fine, but now the first segment doesn't respond. If I click on segments 2 through 4 my controller's method is called as expected. If I click on the first segment... nothing.
I suspect there is another flag somewhere that I hit by mistake, but I can't find it. Yes, all of the segments are Enabled. Any ideas?
I would suggest looking through the hierarchy in detail: the tap is possibly trapped by a partially overlapping view.
If a tap does not respond because the size of an element changes, it may because it is hidden by one of these:
an unconventionally long navigation item
a view with no visible content
a title view
This amazing tool has saved me time and again: Spark Inspector. It shows you the intricate overlapping layers of all your UIViews.
I would like to make a table-view with expanding ability.
When you press a row, the row should expand to show options like delete, copy and so on.
I have found an example for iOS, but I didn't get it running on Mac OS X, because NSTableView and UITableView are very different.
http://www.cocoacontrols.com/platforms/ios/controls/kofiles
Has anyone another template?
Or maybe even get this example running on Mac OS X?
I don't have code to hand you but you can use a view-based NSTableView. Your prototype view can resize itself to include controls if it's selected. All that's a bit complex to condense into a reasonably brief answer but if you use a view-based table view and treat the prototype view like any other that would grow and show extra controls, then wire this behavior to the selection state, it should work.
Note: you will have to write some code for the expansion portion, to handle resizing it, showing the controls, and notifying the table view that one of its rows changed height. Lots of documentation and examples exist out there for each individual component of your problem. Post more specific questions as you run into roadblocks.
I'm trying to implement a sort of drag functionality into my app. As a simplistic example imagine I have a 2x2 square of buttons, so four buttons total. Clicking a button will perform some other functionality however I want when they hold and drag one of these buttons for it to do something else (ideally if you drag one button and drop it while in the space of another button the two buttons will swap places, as long as I can get dragging and dropping working the swap should be easy).
I've done some research and followed a few tutorials but seemed to get errors at one step or another with all of those. It seems ListViews and GridViews have some drag and drop functionality in them already , but I had trouble properly arranging my buttons (there are many more than four and they are in very specific positions, like a diagram) inside these views, let alone getting drag and drop working with them.
How would I go about doing this? Ideally I could just tag these buttons as draggable, and then on a drag-drop event check for a drop position, then if the position is valid perform a swap method. I just can't seem to figure out how to make them draggable or how to have an event that checks a drop position.
Thanks.
Easy peasy, create a custom control that looks the way you want it to, set ManipulationMode to TranslateX|TranslateY, handle manipulation delta events to update positioning with something like a Canvas or TranslateTransform and when manipulation completes - either make it click or animate to the new position. From my experience - getting any other manipulations to work with a regular Button class just isn't working and since a button is a really simple control - it is easier to create your own than try to extend the existing one in such cases.
I have some XIB files which are very difficult to edit because many of the subviews overlap each other completely. For example, if I position a popup volume slider where it will pop up, it covers some UILabels which become impossible to click. My only chance to be able to edit them is to double-click on them in the Document window tree, move them aside, edit, then move them back. Sometimes there are 3 or more widgets that occupy the same location in the XIB, even though only a few are visible at a time while the application is running.
How are conditionally-visible screen elements actually supposed to be organized?
I would like to be able to hide groups of views to reveal what's beneath them, but I don't see a way to do that in IB.
If I create UIViewControllers for every group, I can edit them in separate windows, but I can't see them in context, and I need a lot of view controllers...
Tip: Hold down shift while right clicking the location of the object you wish to select.
I don't think IB is able to hide groups of views during design-time, but there's no reason you couldn't add that behavior yourself using an IB plugin.