scroll problems with NSTableView in a custom view embedded in an NSScrollView - cocoa

I have a right hand panel area in my app that's a tall vertical custom view (let's call this the column view) that contains 2 tableviews. Each tableview does not scroll, and although they are embedded in the standard clipview and scrollview, the vertical height of the tableview is the same as the total number of rows it contains, and bounce is disabled. As the number of rows increases, the background column view increases in height and needs to scroll vertically. It's also embedded in a scrollview. This sounds more complicated than it is, here's a pic:
Scrolling of the background column view works fine as long as the mouse pointer is not inside the red boxes, i.e., over the tableviews. I want to be able to vertically scroll regardless of where the mouse is located within the column view. Any ideas?
Update: here's a mainstream example of where tableviews embedded in a scrollview work correctly, in Tweetbot (assuming those sections are tableviews)

If you want to have scroll view inside other one (red area). You need to disable inner scroll view scrollWheel action. You can achieve that by writing custom NSScrollView subclass, and adding following method :
- (void)scrollWheel:(NSEvent *)theEvent {
// If scroll is disabled, send action to next responder
if (self.scrollEnabled == NO) {
[self.nextResponder scrollWheel:theEvent];
}
else {
[super scrollWheel:theEvent];
}
}
But don't think you need to have scroll view inside other scroll view. Rather you could use one table view with 2 kinds of cells, one for 'section header' and other for 'cell'.
This way you have one table view with multiple sections - just like in iOS.

Related

How Can I Make a View, With a Tab View in It, Scrollable?

I got an NSTabView inside an NSView. That NSView is in an NSClipView, which in turn is in an NSScrollView. It looks like this (NSTabView in green, and NSView in red):
As you can see, the content of NSTabView gets clipped, and no scrollbars appear (since the view doesn't expand beyond the window).
How can I make NSTabView take up as much space as it needs (doesn't clip out), and expand the NSView with it? Then, NSScrollView can deal with the scrolling of the overgrown NSView.
Since my content changes dynamically, I don't want to put in some hard values for the width and height of NSTabView's superview.
This is only part of it; here's now the overall hierarchy looks:
I want the NSTabView's superview to be scrollable instead of clipping out, like this:
The setup I'll describe is for an NSTabView that will pin to the top, left, and right sides of the scroll view. Note the NSTabView could be replaced with any other NSView, the setup is the same.
Starting with you putting a scroll view into the xib/storyboard, you'll have NSScrollView -> NSClipView -> NSView (document view). Constrain the NSScrollView to the edges of the window. Drop your NSTabView onto the NSView instance. Add constraints so that your NSTabView edge constraints equal the NSView and define a height constraint either explicitly or implicitly with other content inside the tab view that defines it.
Personally I like to change the NSView instance (document view) layout to use constraints, by default it uses autoresizing masks and this makes it difficult to keep it in sync with the NSTabView. We want the document view to be pinned to the top, left, and right sides of the scroll view. The size of this view is what determines the scrollable region so we want it to be the same size as the NSTabView so the height of the tab view will determine the scrollable area.
To change this, select the document view, and under the Size Inspector we want to change the "Layout" type to "Automatic".
Lastly, add constraints to the top, left, and right and you should be good to go.
If you want the scroll view to start at the top rather than the bottom, you should subclass the document view and override isFlipped:
class FlippedView: NSView {
override var isFlipped: Bool { true }
}

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.

NSTableView displaying incorrectly in NSSplitView

I have an NStableView embedded in an NSSplitview.
The table will display, but when it does, the first three or so rows are not visible until I reize the window and/or split view. Then, it will snap into place and function perfectly fine until I quit.
Has this ever happened to anyone? Is there a simple method I can call on the view or table to get it to redraw?
This is how it displays when the view is first loaded (note: the user can scroll the table up and see the top row highlighted, but never get to it)
after resizing the window, the table view suddenly snaps into place and appears as it should:
You could try a [_yourSplitView display] to force a redraw of the NSSplitView. If I remeber correctly the SplitView will redraw all its subviews.
Try experimenting with where you use this, as result may vary depending on where in the init order you call this.
I actually got this working by calling the subview and then just resetting the position of the splitview divider.
NSView *v = [vc view];
[self.superDisplayView addSubview:v];
[self.SourceListSplitView setPosition:250 ofDividerAtIndex:0];

How to place an NSButton over an NSTableView

1) No table behind button
2) Table loaded
3) After scrolling
If I place a button over an NSTableView I get artifacts being left behind after scrolling. Does anyone know how to fix this?
My current solution is just to split the section with the table into 2. The lower portion is a disabled button in the background.
Try the NSScrollView method
- (void)addFloatingSubview:(NSView *)view forAxis:(NSEventGestureAxis)axis
All tableviews should normally be inside a ScrollView.
I had a similar problem and solved it, see Why does an NSTextField leave artifacts over an NSTableView when the table scrolls?. Essentially OSX will draw the contents of the table and let the parent scroll view move the cached contents avoiding redraws to be performant. By subclassing the parent scroll view it can be forced to refresh the table hooking the reflectScrolledClipView: method. Then the whole table, including overlays, will be redrawn with each scroll.
That's because the scroll view is set to copy its contents when scrolling and only redraw the newly-uncovered part as a performance optimization. To turn that off, use
myTableView.enclosingScrollView.contentView.copiesOnScroll = NO;
though that will make scrolling use more CPU (you can also do this in the XIB, look for a 'copies on scroll' checkbox).
Probably a better approach would be to switch the scroll view and the button to be layer-backed:
myTableView.enclosingScrollView.wantsLayer = YES;
myButtonView.wantsLayer = YES;
(Again, you can set this in the 'Layers' inspector of the XIB file, where you can click a checkbox next to each view to give it a layer) Now, the scroll view will only copy stuff from its own layer (which no longer includes your button). Also, now all the compositing of the text view will be done using in the graphics card. This works fine with an opaque push button, however, if you put text on a transparent background in its own layer (e.g. if you have a transparent pushbutton with a title), you lose sub-pixel anti-aliasing.

View is moved up when using vertical autoresize

In my custom drawn window I have a NSTextView under which I'd like to have NSScrollView separated by empty space. That's how I've set it up in xib.
In interface builder it looks fine, with nice space between the two of them
But when I run the program, the scroll view gets moves upwards, actually covering the text view:
But when I disable vertical autoresize of the scroll view, everything is working as it should.
text view and scroll view are under NSView so they are siblings to each other.
Most probably it was shortcoming of the system as the scroll view was being completely hidden and so then it was probably moved.
I've worked it out by subclassing NSScrollView and overriding
- (void)resizeWithOldSuperviewSize:(NSSize)oldSize_;
So now I can position the scroll view exactly as I wish.

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