I need something like this
+ scrollview
|
|__ moving content
|
|__ non moving content
The tricky part is that I'm modifying an existing piece of code where I can't use the
scrollview parent to set the "non moving content" as it's child. The non moving content
must be a scrollview child. I was thinking of attaching it to the background view but
I don't know how to access the UIScrollview's background view.
I believe the "recommended" way to do this is to override layoutSubviews in a custom UIScrollView subclass. This was covered (IIRC) in a 2010 WWDC session you ought to be able to get if you are a developer program member.
Assuming you can't subclass UIScrollView (given your restrictions on modifying existing code), you can do something like the following.
Let "staticView" be the "non moving content" you wish to keep fixed:
UIView *staticView;
Create an ivar (probably in your view controller) to hold its initial center:
CGPoint staticViewDefaultCenter = [staticView center]; // Say, in viewDidLoad
Make your view controller the scroll view's delegate if it isn't already, then implement something like the following:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGPoint contentOffset = [scrollView contentOffset];
CGPoint newCenter = CGPointMake(staticViewDefaultCenter.x + contentOffset.x,
staticViewDefaultCenter.y + contentOffset.y);
[staticView setCenter:newCenter];
}
This will cover the simple case of a scrollable view. Handling a zoomable view gets a little trickier and will depend in part on how you have implemented your viewForZoomingInScrollView: method, but follows an analogous procedure (this time in scrollViewDidZoom: of course).
I haven't thought through the implications of having a transform on your staticView - you may have to do some manipulations in that case too.
Related
I set up two NSViews (a toolbar which overlaps view1) with the help of the interface builder / auto layout and then in -(void)awakeFromNib I call
[self.view1 setWantsLayer:YES];
[self.toolbar setWantsLayer:YES];
to make the views layer-backed so I can animate them later on. I found out that if I call setWantsLayer on the toolbar after I call it on view1 it gets displayed over view1 not caring about the order in the interface builder. So far, so good.
My question is: how can I change the order of the views later on in code. Calling
self.toolbar.zPosition = 0;
self.view1.zPosition = 1;
doesn't do anything. Since I'm feeling not so confident with CALayers:
Is there something I'm missing?
And is there a good tutorial for CALayers - I read the docs, but didn't understand everything (concept of layer-hosting views, sublayers, ...)
edit
an image for better understanding (I want to animate the transparency of the green view so the black toolbar is over the red view and the green view is gone. and back to green view):
You need to add the second view relative to the first using addSubview:positioned:relativeTo:. The layer index is relative only to that layers in the parent layer, not the view hierarchy its self.
For example,
[hostingView addSubview:topView
positioned:NSWindowAbove
relativeTo:bottomView];
I'm developing a little app with two custom views in Cocoa. The custom views are controlled by two separated classes. I've a NSTimer set up in my AppDelegate that asks one of the views to draw it self, but the the problem is that both views are being drawn.
My method looks like this:
- (void)timerMethod:(NSTimer *) theTimer
{
[theOtherView setNeedsDisplay:YES]; // The View that needs to be drawn
[theBackGroundView setNeedsDisplay:NO]; // Doesn't really do anything, thought it might though.
}
I hope someone can point me in a direction to how I should draw my view instead.
Layer-hosting NSViews (so NSViews that you supply a CALayer instance for and set it with setLayer:) can obviously contain subviews. Why obviously? Because in Apple's own Cocoa Slides sample code project, you can check a checkbox that switches the AssetCollectionView from being layer-backed to being layer-hosting:
- (void)setUsesQuartzCompositionBackground:(BOOL)flag {
if (usesQuartzCompositionBackground != flag) {
usesQuartzCompositionBackground = flag;
/* We can display a Quartz Composition in a layer-backed view tree by
substituting our own QCCompositionLayer in place of the default automanaged
layer that AppKit would otherwise create for the view. Eventually, hosting of
QCViews in a layer-backed view subtree may be made more automatic, rendering
this unnecessary. To minimize visual glitches during the transition,
temporarily suspend window updates during the switch, and toggle layer-backed
view rendering temporarily off and back on again while we prepare and set the
layer.
*/
[[self window] disableScreenUpdatesUntilFlush];
[self setWantsLayer:NO];
if (usesQuartzCompositionBackground) {
QCCompositionLayer *qcLayer = [QCCompositionLayer compositionLayerWithFile:[[NSBundle mainBundle] pathForResource:#"Cells" ofType:#"qtz"]];
[self setLayer:qcLayer];
} else {
[self setLayer:nil]; // Discard the QCCompositionLayer we were using, and let AppKit automatically create self's backing layer instead.
}
[self setWantsLayer:YES];
}
}
In the same AssetCollectionView class, subviews are added for each image that should be displayed:
- (AssetCollectionViewNode *)insertNodeForAssetAtIndex:(NSUInteger)index {
Asset *asset = [[[self assetCollection] assets] objectAtIndex:index];
AssetCollectionViewNode *node = [[AssetCollectionViewNode alloc] init];
[node setAsset:asset];
[[self animator] addSubview:[node rootView]];
[nodes addObject:node];
return [node autorelease];
}
When I build and run the app and play around with it, everything seems to be fine.
However, in Apple's NSView Class Reference for the setWantsLayer: method it reads:
When using a layer-hosting view you should not rely on the view for
drawing, nor should you add subviews to the layer-hosting view.
What is true? Is the sample code incorrect and it's just a coincidence that it works? Or is the documentation false (which I doubt)? Or is it OK because the subviews are added through the animator proxy?
When AppKit is "layer hosting" we assume you may (or may not) have a whole subtree of layers that AppKit doesn't know about.
If you add a subview to the layer hosted view, then it might not come out in the right sibling order that you want. Plus, we sometimes add and remove them, so it might change depending on when you call setLayer:, setWantsLayer: or when the view is added or removed from the superview. On Lion (and before) we remove the layers that we "own" (ie: layer backed) when the view is removed from the window (or superview).
It is okay to add subviews...their children-sibling-order in the sublayers array just might not be deterministic if you have sibling-layers that aren't NSViews.
I don't know what's the "right" answer to this. But I do think that the CocoaSlides example works within the boundaries of what the docs say you "shouldn't" do. In the example, look at where the insertNodeForAssetAtIndex: method is called, and you'll see that it only happens when the view is being populated, before it ever is assigned a layer or has setWantsLayer: called on it.
The docs don't say that a layer-hosted view can't contain any subviews, they just say that you can't add and subviews to one. At the point in time when those subviews are added, the main view hasn't yet become a layer-hosting view. After it has been turned into a layer-hosting view by having a manually created layer assigned to it, no more subviews are added.
So there's really no contradiction between the docs and this particular example. That being said, it could be interesting to explore this further, maybe by switching on the QC background layer right from the start, e.g. by sticking a [self setUsesQuartzCompositionBackground:YES]; right inside initWithFrame:.
SPOLIER ALERT:
It seems to work just fine. The creation of the display is a bit slower (not surprising with all that QC animation going on), but apart from that it's smooth sailing.
One comment about this code from Apple: it's busted.
When you first start the app up, note the nice gradient background. Turn QC on, then off.
Poof, no more gradient background.
I have an NSView in IB which sits above the app window. I have a subclass of NSView (AddSource) which I assign to the NSView.
On awakeFromNib I instantiate the view:
//add a new Add Source class
addSourceView = [[AddSource alloc] initWithFrame:NSMakeRect(0.0, 959.0, 307.0, 118.0)];
[[winMain contentView] addSubview:addSourceView];
in addSourceView's drawRect method I am adding a white background to the view:
[[NSColor whiteColor] set];
NSRectFill(rect);
[self setNeedsDisplay:YES];//added this to see if it might solve the problem
In winMain's contentView I have a NSButton that when clicked slides the addSourceView onto the window:
NSRect addSourceViewFrame = [addSourceView frame];
addSourceViewFrame.origin.y = 841.0;
[[addSourceView animator] setFrame:addSourceViewFrame];
But it seems as if the app is painting over the IBOutlets I placed on the NSView in IB. If, in IB, I repoistion the NSView so that it is on screen when the app launches everything works fine, the IBOutlets are there as well as the background color.
I'm not sure why this is happening. I've done this before with no problems. I must be doing something different this time.
Thanks for any help.
*note - on the 3rd screen capture, when I say this is what the app looks like when opened, that's when I hard code the Y position of the NSView. When it is functioning correctly it should open as screen capture 1.
Most likely your buttons and custom view are siblings, i.e. they are both subviews of your window's content view. Since siblings are "Stacked" depending on the order in which they are added, when you add the view in code it is being added on top of the buttons. You should be able to fix it by explicitly specifying where the view should be positioned relative to its new siblings like so:
[[winMain contentView] addSubview:addSourceView positioned:NSWindowBelow relativeTo:nil];
which should place it below any existing subviews of your window's content view. Also, remove the setNeedsDisplay: line in drawRect, that leads to unncessary, possibly infinite, redrawing.
EDIT: OK I see what you're doing.
I would suggest creating a standalove view in the NIB by dragging a "Custom View" object into the left hand side (the vertically-aligned archived objects section) and adding your controls there, that should ensure the controls are actualy subviews of the view, then you can just create a reference to the archived view in code, and add/remove it dynamically as needed.
Honestly though, you should probably be using a sheet for these kinds of modal dialogs. Why reinvent the wheel, and make your app uglier in the process?
You added TWO AddSource views to the window. You added one in IB - this view contains your textFields and buttons that are connected to the IBOutlets and it is positioned outside the window.
Then in -awakeFromNib you create another, blank AddSource view (containing nothing) and animate it into the window.
I can't recommend highly enough the Hillegass as the best introduction to IB and the correct way to build Cocoa Apps.
Also, Assertions can be useful to make sure what you think is happening is actually what is happening.
If you are certain you added a button to your view in IB, assert it is so:-
- (void)awakeFromNib {
NSAssert( myButton, #"did i hook up the outlet?");
}
NSAssert is a macro that has zero overhead in a release build.
Calling [self setNeedsDisplay:YES] from -drawRect just causes the same -drawRect to be called again. This will give you big problems.
I have made a window with an NSOpenGLView that I am rendering openGL content into.
I want to add some buttons and text fields to the view: I can add NSTextFields and NSButtons using interface builder (or code) but they do not appear.
NSOpenGLView is documented as not being able to have sub views, so I then made my own CustomGLView by deriving directly from NSView and implementing the code to create and use a NSOpenGLContext in it. But the subviews are still not appearing :- the OpenGL context paints over them.
On Windows this problem does not exist:- Windows used to host OpenGL MUST have the WS_CLIPCHILDREN and WS_CHIPSIBLINGS styles set ensuring that any peer, or sub children (views) will not be obscured by the OpenGL surface.
How do I get subviews to display over a NSView thats drawing using OpenGL ?
You have 2 choices:
Create a window just for the text field. Add as a child window of the one hosting the OpenGL view. Major downside is you have to manage positioning it correctly if the Open GL view is moved.
Set up your view hierarchy like so:
Layer-backed view
Layer-hosting view whose layer contains an OpenGL layer
Text field
Simply call -setWantsLayer:YES on the subviews of the NSOpenGLView.
NSOpenGLView cannot have subviews according to the documentation. Even if you subclass the NSOpenGLView, that will change nothing.
What you can do is to create a NSView that will hold both the NSOpenGLView and the NSTextField. You then overlap them in the right order to make one draw atop the other.
I'm not heavily into OpenGL yet, but it's my understanding that you can accomplish the visual effect of subviews with Quartz Extreme using layer-backed views; however, those may be problematic. Since subviews are not supported directly, any solution is liable to be a hack.
Indeed, the solution in that link actually hacks a second window to appear over your OpenGL display, the second window displaying the Cocoa views you desire.
The following code (from the above link) is something I've not tested (again not being an OpenGL guy by nature -- yet), but appears like a fairly clever approach:
// This is the GL Window and view you already have
glWindow = [[GLWindow alloc] initWithContentRect:windowRect];
glView = [[[GLView alloc] initWithFrame:NSMakeRect(0, 0, windowRect.size.width, windowRect.size.height)] autorelease];
[glView translateOriginToPoint:NSMakePoint(glView.bounds.size.width/2, glView.bounds.size.height/2)];
[glWindow setContentView:glView];
// And here's your transparent UI window
uiWindow = [[TransparentWindow alloc] initWithContentRect:windowRect];
uiView = [[[NSView alloc] initWithFrame:NSMakeRect(0, 0, windowRect.size.width, windowRect.size.height)] autorelease];
[uiView translateOriginToPoint:NSMakePoint(uiView.bounds.size.width/2, uiView.bounds.size.height/2)];
uiView.wantsLayer = YES;
[uiWindow setContentView:uiView];
[glWindow addChildWindow:uiWindow ordered:NSWindowAbove];
Again, I've not tested this, but it looks like it will get you the visual effect you desire.
The text can be rendered into a texture -- I just used this for a project, did a lot of looking for sample code, and ultimately found Apple's GLString demo code, which was an absolute trove of how-to:
http://developer.apple.com/library/mac/#samplecode/CocoaGL/Listings/GLString_m.html
I haven't tried adding buttons, but you can, of course, draw your own and comparing the positions of click events with those of your buttons...
This was my solution:
1) Create a parent NSView (let's call it parentView).
2) Add an NSOpenGLView Child to parentView.
3) Add an additional NSView Child to parentView (make sure this is after the OpenGLView within the hierarchy). You can add additional TextFields, etc. to this view.
4) In the ViewController for the parent make sure you call [parentView setWantsLayer: TRUE]; I did this within -(void) viewWillAppear
1) The NSOpenGLView can have a subview. It can have plenty even.
2) The reason some views, controls and other elements are being bullied by NSOpenGLView is due to the loading process when the Application launches. I.e If you add a slider or textfield above and into the content view of the window where the NSOpenGLView also resides, upon Application-Launch that textfield will most likely wind up beneath the NSOpenGLView.
This is an Apple Bug. And they know about it.
You can solve it quite easily even without adding a subview to NSOpenGLView...
In Interface Builder drag i.e. a CustomView into the canvas (Not the view). And set it the way you want it with sliders, text and what not. Then create an outlet (Call it i.e topView) in your view controller. Then somewhere in your code... Perhaps (applicationDidFinishLaunching) add this line...
[_window.contentView addSubview:_topView];
(Do your positioning & layout)
This will do the exact same thing as if you had dragged it into the contentView yourself inside IB. Only it will draw the darn thing in the correct Z position.
You loose IB's constraints this way and have to it manually
One could also just subclass and CAOpenGLLayer and use that as a backing layer inside of a regular NSView. There too it is drawn correctly...
Here is Apple's way of wanting to do that. CALayers are a Godsend ;)
Enter following String ** NSOpenGLLayer** in search and hit enter to get to where it is...
NSOpenGLLayer
Hope this helps....