I am trying to create a view for a kind of brainstorming application like, for example, OmniGraffle, with elements that contain textviews and can be dragged around. (Also, the should be connectable with arrows, but that is not (yet) the problem)
I did my homework and searched via google and read books about cocoa, but there seems to be no similar example around.
Since I am also new to cocoa, I’m a bit helpless here.
The thing I am sure of is, that I need a custom view in which I can create my elements - what I tried until now to do that is:
First, I searched for the syntax to add subwindows to a window to create my elements. Subwindows, I imagined, would automatically be movable and come to front and so on.
The problem: As the experienced Cocoa-programmers of you probably are not surprised, I was stunned to find nothing about anything like that - this seems to be something, that is just not intended in Cocoa?!
Then I thought about creating subviews that contain a custom view for the title bar drawing (where the user can click to drag the element) and a NSTextView.
Problems:
I read, that it is not so clever to create dozens of subviews in a window because that would be very slow (or would that be not so bad in this case because all the subviews would be instances of always the same class?).
Also I can’t find out how to load a subview from a nib- or xib-file. Would I need a viewController? Or would that make the dozens-of-instances-problem even worse?
And Apple tells you not to overlap subviews (okay, that would be not so important, but I really wonder how the guys at OmniGroup made OmniGraffle...)
Because of that, I now wanted to do the title-bar-drawing in the surrounding custom view and create the textview programmatically (as I understand, a text-“view“ ist not really a view and takes its functionality from NSCell to reduce all the effort with the views?).
Problems:
Even that failed because I was not able to create a textview that doesn’t fill the complete window (the initWithFrame: of the [[NSScrollView alloc] initWithFrame: aRect] just seems to be ignored or do I get that wrong?).
Also, there should be some buttons on each element in the final application. I imagine that would be easier to accomplish with a subview from a nib-file for each element?
Well, now that nothing works and the more I read, the more problems seem to occur, I am pretty confused and frustrated.
How could I realize such a program? Could someone please push me in the right direction?
I created a class for the draggable elements where I save position, size and text in instance variables. In my view, every new element instance is added to an array (for now, this works without a controller). The array is used to draw all the elements in a loop in drawRect:. For the text of the element I just use a NSTextFieldCell which is set to the saved text from every element in the same loop.
That way it is also possible to overlap the elements.
Related
I'm currently working on a prototype for a todo type app. I have a table which contains the user tasks. What I want to do is only present the user with pertinent task information. But to edit additional information, they would click on a disclosure button to expand the cell.
I was thinking of two possible ways to handle this:
Expanding NSTableViewCell
Using an NSStackView as the contents of each cell
If using the NSTableViewCell, I would probably have two NSViews to represent the cell (top part and lower part).
If using the NSStackView, I'd have an easy means of encapsulating the parts.
I suppose another method could also be just building it entirely with NSStackView.
The more difficult aspect of this seems to be related to the actual expansion/collapse of the cell.
I understand this could be deemed the type of question that's asking for an opinion. I've never built a MacOS app. So I'm looking for some guidance as to the best method to approach the problem versus spinning my wheels on approaches that are destined to not be productive.
Thanks!
In the end, it looks like the best thing to do is use an NSTableCellView with two NSViews for the top and bottom half. I had the case of this as well as the NSStackView working. But in the end, I found that using NSStackView to collapse or expand requires a call to make noteHeightOfRows work anyways.
So it would initially seem that it's not worth the effort of expanding it unless I have a more complicated cell where say I wanted a top, middle, and bottom, where the middle could expand and contract. While I would still need to use noteHeightOfRows, it would allow for it.
However, there is one benefit of using the NSStackView. The animation is much smoother for the collapse. I've found the NSTableCellView method with a top and bottom NSView shows signs of "tearing" as it collapses. This is what appears in the bottom edge, while horizontal, jitters. This is particularly apparent if you either spam the button or if the cell is selected because the bottom of the outline can sometimes grow in height.
I also found that when using NSAnimationContext to help make it look a little smoother, I'd see strange behavior. Like the hide would happen at the wrong time (even though it was in the completionHandler. I think the root cause of that are what becomes overlapping animations.
I am quite new to NSTableView but as I tried to get things straight, I took a look at InterfaceBuilder!!
TableView hierarchy
I understand that objects are responsible for scrolling and clipping. TableView is the real NSTableView instance. The object titled function list ist the NSTableColumn below that is my TableCellView objects. What I don't understand is the object TextCell. It doesn't seem anything to do. Even wrong colors and alike have no effect at all. I am using a view based variant. Is the TextCell solely for cell based TableViews?
I found that part not quite well documented. I am planning on building custom views for my table. So I was thinking a thorough understanding would be a good approach.
Yes, it's strange that that's still there. It's useless and has no effect on anything, but you can't delete it. Ignore it.
Although I know of a solution to this problem, I am interested if someone can explain this solution to me. I also wanted to get this out there because I could not find any mention of this problem online, and it took me several hours over several days to track down. I have an NSTableView behaving strangely regarding redraws and its selection. The problem looks like this:
Table contents fades in, instead of appearing instantly upon it's appearance on screen. When scrolling through the contents, the newly appearing rows also fade in. When you make a selection (single or multiple), and scroll it off screen, then make another selection (that should replace, not add-to first selection), the first selection does not get cleared properly. If you scroll back to it, it is still there, in addition to your new selection. This is a display-update problem, not selection problem - i.e. your new selection is valid, it is just displayed wrong.
I tracked this through the NSArrayController I was binding to, the underlying Array, sorting, all the connections, and settings, etc., but all that has nothing to do with it.
What solved the problem was:
In the View Effects (right-most) Inspector, uncheck "Core Animation Layer" for the Window's main view.
Can anyone explain what is happening here, and perhaps improve upon the solution ?
It looks like Core Animation and NSTableView aren't getting along so well. The "fading" effect is a by-product of the way core animation works. When you have core animation in one view, it is also enabled in all of that view's subviews.
I don't recommend using core animation on the Mac unless absolutely necessary, because some interface elements (NSTextView and NSTableView, for example) aren't compatible with it. iOS has much better support for table views and such using core animation, mainly because it was designed with core animation in mind.
I know that some more simple UI elements are compatible (NSTextField and NSButton, for example).
If you absolutely need core animation in the rest of the window, put all the other views in a subview of the content view, while leaving the table view directly in the content view. You can then enable Core Animation in the other view.
Commenters, feel free to add to the list of what is and isn't compatible.
I have been trying to create a simple swipe transition. However buttons seem immune to any CAAnimation that crops.
I am trying to get it so that a bar moves across the screen and as it goes over the button it removes the part it has just gone over.
I have tried bounds.width, size.x and many other key-value paths to achieve the affect but I haven't got what I wanted. It just relocates the text which always remains entirely visible
I have also tried changing the UIButton to a UIImage but the text does not seem to print on a UIImage.
I tried using masks too but I have heard they should be used as infrequently as possible as they consume the phones resources. I didn't really get very far with this either anyway as I hadn't used them much before.
I also tried placing it in a container view and then change the dimensions of that but again all of the text remained entirely visible.
I know I could have a view hide the button but I am trying to reveal the view behind as the bar swipes.
Does anyone have any suggestions of how to achieve a swipe transition on a UIButton?
Help would be much appreciated.
Thanks
I think what you're looking for really is a mask. See the tutorial here:
http://iosdevelopertips.com/cocoa/how-to-mask-an-image.html
What I'd do in your situation is create a custom UIButton class, and add a mask as in the tutorial, then animate the position of the mask. Slide the mask of, nothing shows. Slide it on, part shows until the whole thing is visible.
Edit: I haven't really heard anything about hogging resources, especially since it appears to be simple core graphics.
I’m starting to develop my first full-blown Cocoa application containing a view which I would like to behave (and look) similar to Automator’s AMWorkflowView.
The basic features I’d like to achieve:
Positioning of subviews
Display of subviews in expanded / collapsed states
Multiple selection
Drag and drop
In order to get accustomed to Cocoa, I started with a custom NSView which mainly served as a container for the custom subviews and handled their positioning and multiple selection.
The subviews are also subclasses of NSView, and contain a variable amount of views themselves, like buttons, labels and popup menus, and therefore can have different heights.
This worked quite well, but before going on, I want to make sure to have everything neat and tidy according to the MVC pattern.
I suspect that there already is a class in Cocoa that facilitates the implementation of a view container, like maybe NSCollectionView.
It seems that there is no (easy) way to display differently sized views in an NSCollectionView, though. Should I continue implementing my custom NSView (probably using an NSArrayController for selection and sorting support), or are there better ways to go?
Any help is much appreciated
Unfortunately the answer is you'll have to roll your own. NSCollectionView does not allow for variable-sized items (which also rules out expanded/collapsed states).
For a limited number of items, you can accomplish this rather easily (you just need a container view that arranges the subviews properly when asked to layout, then you need to make sure you re-layout when things change). For many subviews, however, you'll need to take care to be as efficient as possible. This can start with laying out as little as possible (only those "after" the resized view, for example) and get as complex as caching a visual representation of a prototype view, drawing the cached images (fast!) for all but the view being edited, and only using/positioning a "real" view for the view being edited.
Drag and drop works the same as it always has, but none of the above accounts for the pretty animation NSCollectionView gives you. :-) It's fast and beautifully-animated precisely because all the subviews are uniform (so the layout calculations are fast and simple). Once you add irregular sizes, the problem becomes significantly more complicated.
The bottom line: If you need variably-sized views, NSCollectionView will not work and you'll need to roll your own or find someone else's shared code, but performance and beautiful animation will not be easy.