I want to make the NSTableView call height for row before it calls view for column on scroll. (Similar to what UITableView does). Is this possible ?
I really wonder why do you need it,because there can be an alternative for this.
You can first look at
Callbacks When an NSScrollView is Scrolled?,
and then actually call noteHeightOfRowsWithIndexesChanged: which internally calls height for row.
I am just trying to help,but i highly suggest please don re invent the wheel.
Related
I'm trying to figure out a way to have a NSTableColumn be pinned to the left side of my NSTableView. What I have been thinking of is putting two NSTableView's side by side, where the first one contains the 'pinned' column and the second on contains the dynamic data. Setting the first table to disable horizontal scrolling, then detecting when either table is scrolled vertically and keeping the two in sync.
What I'm wondering, is if anyone else has any experience in doing something similar? I don't want to re-invent the wheel if its already been done.
Thats exactly what I did. Two NSTableView's directly beside each other. The first I subclassed the NSScrollView and modified the scroll events to do nothing. The second I subclassed again the NSScrollView and modified the scroll events to cause the header to mirror it. Works great.
I'd really like to create a table view that is segmented similar to the screen shown ( which is taken from the XCode->Build Phases view ). To be honest, I'm a bit lost on how to start there.
I could use a NSTableView + a custom NSTableCellView that manages the expanding/collapsing behaviour, but I'm entirely not sure if the resizing of an individual row is possible or permitted ( the doc isn't too verbose here ).
The second approach would be to choose a NSOutlineView to accomplish this behaviour, yet it would require some serious subclassing to get where I'd like to go.
So, before I'm doing it wrong again, what would you do? Thanks a lot for your time
– Moritz
I am quite sure that is an NSOutlineView (not sure if is one big outline or 4). The subclassing isn't as hard as it looks. The only item that requires custom drawing is the root element (that's the row with the disclosure triangle.)
You see this in iPhone apps like Gilt. The user scrolls a view, and a subview apparently "sticks" to one edges as the rest of the scrollView slides underneath. That is, there is a text box (or whatever) in the scrollView, that as the scrollView hits the top of the view, then "sticks" there as the rest of the view continues to slide.
So, there are several issues. First, one can determine via "scrollViewDidScroll:" (during normal scrolling) when the view of interest is passing (or re-appearing). There is a fair amount of granularity here - the differences between delegate calls can be a hundred of points or more. That said, when you see the view approach the top of the scrollView, you turn on a second copy of the view statically displayed under the scrollView top. I have not coded this, but it seems like it will lack a real "stick" look - the view will first disappear then reappear.
Second, if one does a setContentOffset:animated, one does not get the delegate messages (Gilt does not do this). So, how do you get the callbacks in this case? Do you use KVO on "scroll.layer.presentationLayer.bounds" ?
Well, I found one way to do this. When the user scrolls by flicking and dragging, the UIScrollView gives its delegate a "scrollViewDidScroll:" message. You can look then to see if the scroller has moved the content to where you need to take some action.
When "sticking" the view, remove it from the scrollView, and then add it to the scrollView's superview (with an origin of 0,0). When unsticking, do the converse.
If you use the UIScrollView setContentOffset:animated:, it gets trickier. What I did was to subclass UIScrollView, use a flag to specify it was setContentOffset moving the offset, then start a fast running timer to monitor contentOffset.
I put the method that handles the math and sticking/unsticking the child view into this subclass. It looks pretty good.
Gilt uses a table view to accomplish this. Specifically, in the table view's delegate, these two methods:
– tableView:viewForHeaderInSection:
and – tableView:heightForHeaderInSection:
I've got my custom NSView with a bunch of custom buttons in it, the buttons are added as a subView in the NSView's drawRect method.
Now I'm finding that after pressing a button the drawRect of the parent view is repeatedly called. Sometimes it only stops when I quit the app - I know this from a simple log statement in drawRect.
Now I know there are probably bigger architectural issues in my app causing this, where do I go to begin tracking down what's causing this view to be repeatedly redrawn?
Thanks!
First of all you shouldn't be adding subviews in drawRect:.
Are you doing any custom drawing or are you just adding subviews? If you're not doing any drawing, you should not implement drawRect:.
You want to add the subviews in initWithFrame: and then you want to set the frames of the subviews in layoutSubviews based on self.bounds.
If you have any questions, feel free to ask.
EDIT: Just realized that you were asking about NSView and not UIView. I've never used NSView, but perhaps they work similarly.
EDIT 2: I read a bit about NSView and it doesn't seem to have layoutSubviews. Perhaps you should set the frames in drawRect:? I'm still pretty sure you don't want to add subviews in drawRect:.
I want to achiece the following scenario,
My idea is to have three different tableview. But i have stuck up with the scrolling problem that if i scroll tableview3 vertically, tableview1 & tableview2 should also scroll.
Is there any other idea for implementing this? Or else a solution for my scrolling problem?
Note: The number of columns are dynamic.
Happy Coding
I'm currently in the process of implementing a similar UI system, I gave up on using UITableView for it in order to make things a little more 'dynamic'. Re-implemnting all of UITableView from scratch is a really fun exercise!
If UITableView will still work for you, all you need to remember is tableview's are subclasses of UIScrollView, which has delegate methods for scrolling. Use those, along with setContentOffset and you can trivially sync the scrolling of multiple tables.