I am building an application, where I need to put two seperate NSViews side-by-side when in fullscreen mode. As I have seen, probably there are two ways to do this, either I can make a super NSView and two subviews, or put two NSViews in a NSWindow. The problem is that though the process works for me for one NSView, I can't put them together at the same time. The method setContentView: allows me to set only one view for a window. And the method setSubViews: covers up the whole of the NSView. How can one specify the exact coordinated of the views to place and size them?
An NSWindow only has one root NSView... and that's the Window's contentView. Store any other views in that root view.
Using the Interface Builder offers an easy way of configuring the location/size of views in a graphical way.. but you can manually configure their frames with something around the lines of :
NSView *myView = [[MyCustomView alloc] init];
[[myWindow contentView] addSubview:myView];
[myView setFrame:NSMakeRect( /* ... */ )];
Some reading : NSView
Set one NSView as contentView of NSWindow and add the other two NSView's on using -addSubview method of NSView
Related
I am trying to create a custom NSView that hosts a CALayer hierarchy to perform efficient display. This NSView is then embedded within a NSTableCellView that is displayed by a View-Based NSOutlineView.
The problem is that whenever I expand or collapse an item, all rows are being moved, but the layer's content remains displayed at the position it was before changing the outline.
Scrolling the NSOutlineView seems to refresh the layers and they resync with their rows at that point.
I have debugged this behavior using Instruments and it seems that the scrolling provokes a layout operation which updates the layers with a setPosition: call that should have occured when expanding or collapsing items.
Here is some sample code for a simple layer hosting NSView subclass.
#interface TestView : NSView
#end
#implementation TestView
- (instancetype)initWithFrame:(NSRect)frameRect
{
self = [super initWithFrame:frameRect];
CAShapeLayer* layer = [CAShapeLayer layer];
layer.bounds = self.bounds;
layer.position = CGPointMake(NSMidX(self.bounds), NSMidY(self.bounds));
layer.path = [NSBezierPath bezierPathWithOvalInRect:self.bounds].CGPath;
layer.fillColor = [NSColor redColor].CGColor;
layer.delegate = self;
self.layer = layer;
self.wantsLayer = YES;
return self;
}
#end
I have tried a lot of potential solutions to this problem but I couldn't find any interesting method that gets called on the NSView instance that could be overriden to call [self.layer setNeedsDisplay] or [self.layer setNeedsLayout]. I also tried various setters on the CALayer itself such as :
layer.autoresizingMask = kCALayerWidthSizable | kCALayerHeightSizable;
layer.needsDisplayOnBoundsChange = YES;
self.layerContentsRedrawPolicy = NSViewLayerContentsRedrawOnSetNeedsDisplay;
Can anyone help me figure out how to make this layer display properly inside a NSOutlineView?
I ended up answering my question. The problem wasn't in the way my TestView was implemented. I simply missed one of the steps for enabling CoreAnimation support within the application. The relevant reference is within the Core Animation Programming Guide.
Basically, in iOS Core Animation and layer-backing is always enabled by default. On OS X, it has to be enabled this way :
Link against the QuartzCore framework
Enable layer support for one or more of your NSView objects by doing one of the following
In your nib files, use the View Effects inspector to enable layer support for your views. The inspector displays checkboxes for the selected view and its subviews. It is recommended that you enable layer support in the content view of your window whenever possible
For views you create programmatically, call the view’s setWantsLayer: method and pass a value of YES to indicate that the view should use layers.
Once I enable layer support on any of the NSOutlineView's parents, the various glitches are solved.
It is difficult to read the NSOutlineView reference documents and find the information about cell reuse that is likely giving you fits here.
You may have looked at outlineViewItemDidCollapse: but it's kind of a useless for our issue, because it doesn't have a pointer to an NSView, and that's because it's older than view-based outline views.
Perhaps the one helpful mention, buried within the NSOutlineViewDelegate protocol, down in the section on view-based NSOutlineView methods, there is a single mention within outlineView:didRemoveRowView:forRow: that:
The removed rowView may be reused by the table, so any additionally inserted views should be removed at this point.
In other words, when you call the outline view's makeViewWithIdentifier:owner:, for a cellView or rowView with a particular ID you often get a recycled view. Especially often because of collapse. Incidentally, that method is from the NSTableView superclass, and in that reference, there's also this comment:
This method may also return a reused view with the same identifier that is no longer available on screen. If a view with the specified identifier can’t be instantiated from the nib file or found in the reuse queue, this method returns nil.
So you have the option of altering the view hierarchy or niling properties in didRemoveRowView:forRow. However, buried within a third cocoa reference, that for NSView, there is within the commentary on prepareForReuse, this comment:
This method offers a way to reset a view to some initial state so that it can be reused. For example, the NSTableView class uses it to prepare views for reuse and thereby avoid the expense of creating new views as they scroll into view. If you implement a view-reuse system in your own code, you can call this method from your own code prior to reusing them.
So, TL;DR, you need to implement prepareForReuse.
The pertinent references are (mostly) the superclasses of both NSOutlineView and NSTableCellView.
And, FWIW, there was a similar question here, where the questioner seems to indicate things are even worse than I think, in that NSOutlineView is more creative behind the scenes than NSTableView.
In my own work with outline views and embedded NSTextViews, I've seen wildly terrible rendering hiccups relating to expand/collapse/scroll that I seem to have managed in just the NSOutlineViewDelegate methods. On iOS they did everyone the favor of renaming makeViewWithIdentifier to the more explicit dequeueReusableCellViewWithIdentifier.
You shouldn't have to enable layer backing for any of the ancestor views (like the outline view).
In my experience, the layer immediately assigned to a view (as opposed to sublayers) doesn't need its bounds, position, or autoresizing mask to be set. It is automatically made to track the bounds of the view. In fact, I would avoid setting those properties, just in case that breaks the automatic synchronization with the view's bounds rect.
So, the question is: how are you arranging for the view to move or resize with its superview? Are you using auto layout? If so, did you turn off its translatesAutoresizingMaskIntoConstraints? If yes to both, what constraints are you setting on the view? If no to either, how did you position the view within its superview? What frame did you set? Also, is the superview configured to autoresize its subviews (probably yes, since that's the default)? What is your view's autoresizingMask?
You could also override -setFrameOrigin: and -setFrameSize: in your custom view class and call through to super. Also, add logging to show when that's happening and what the new frame rect is. Is your view being moved as you expect when you expand or collapse rows?
Is there a way to change the "layer" that UIImageView objects are drawn in? Whenever I add an image view to a view controller it defaults to drawing the most recently added one on top of all the others. So if I decide to add a "background" image it is now a "foreground" image and blocks everything else.
There isn't anything in the IB options or in the UIImageView class reference and I haven't been able to find anything here on SO. It's been a problem for a while and it's weird that I haven't seen anything about it before... I think it might just be my semantics coming from a delphi background.
Anyway, does anyone know about this issue / ICANHAZTEHCODEZ to fix it? Or is this just like the UIScrollView problem and poorly supported by the development environment.
This happens when I try to use the editor to arrange the subviews.
You can bring a SubView to Front or Send it background programmatically using
[self.view bringSubviewToFront:yourImageView];
and
[self.view sendSubviewToBack:yourImageView];
when self.view must be the superview of your imageView
In IB, select a UIControl and from top menu bar select Editor->arrage->send to front or back
When you use UIView's addSubview: method, it will add it to the top of the view stack resulting in what you are seeing.
There are numerous other UIView methods you can use to determine the order of subviews. E.g.:
- (void)insertSubview:(UIView *)view aboveSubview:(UIView *)siblingSubview;
- (void)insertSubview:(UIView *)view atIndex:(NSInteger)index;
- (void)sendSubviewToBack:(UIView *)view;
- (void)bringSubviewToFront:(UIView *)view;
Why would anyone subclass a UIView instead of creating our own custom view like this:
CGRect labelRect = CGRectMake(20,20,20,20); //Frame to contain the current view
UILabel *label = [[UILabel alloc] initWithFrame:labelRect];
label.text = #”This is a custom view with out subclassing UIView”
[self.view addSubView:label];
Is don't see any tradeoffs or advantages? Am I missing something?
In a lot of cases where you are just rearranging text, and utilizing some of the built in buttons, labels, etc; it is not necessary to subclass a UIView and can instead be done programmatically through a UIViewController or added to a storyboard/nib file. However, a great example of when and why you would want to subclass a UIView is if you wanted to add some custom touch behavior or drawing to the view that you are using.
So the way I see it, the main considerations in subclassing a UIView comes down to the following:
1) Touch interaction,
2) Custom Drawing
*Note that there may be other reasons you may want to create a view subclass simply from a program organization perspective, but these are the main three that the behavior cannot be delegate to another function, or added directly to the UIView. For example, support for general animations and background image manipulation can all be handled without subclassing UIView.
Touch Interaction - Touch interaction with a UIView can be handled in a couple different ways, you can interact directly with the touch events, or add a gesture recognizer to the UIView. In many cases, you can accomplish everything that you need to through a gesture recognizer (or custom gesture recognizer), rather than attempting to look at the individual touches that are occurring on your view, but if you wanted/needed to access the raw touch events, you would override the following functions to implement the desired behavior:
-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
-(void) touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
-(void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
Custom Drawing - In a UIView you can do basic 2D drawing through Quartz/Core Graphics. One example is that if you were doing a graphing application and wanted your UIView to draw the actual lines for you within its context on the screed. To accomplish this, you would override the drawRect:(CGRect)rect function and list any custom drawing here.
That being said, this is by no means the only way that you could draw a line, and could complete this task without performing custom drawing. For example, that same line, or set of lines, could be drawn into an image buffer by your UIViewController, and then displayed as the background of your view or a subview accordingly. When doing that however, the UIView loses the knowledge of the line on screen, and touch interaction directly with that line becomes more challenging. In the end, keep in mind that there are creative ways to get around subclassing just to display custom drawing, but sometimes from a program design perspective it may make more sense to just create a UIView subclass.
These are by no means the only reasons that you would want to subclass a UIView, but have been the 2 biggest reasons that I have seen used for creating a subclass of UIView. I would suggest that you look at UIView class reference or View Programming Guide for iOS for more details.
for the same reason UIView is subclassed with controls and text layout views in UIKit: because the existing implementations don't do everything, and custom implementation or members are needed (at times).
however, you might subclass UILabel in this case, if you needed to do something specific, or reuse an implementation and subclassing were a good solution.
I would say custom behaviors and custom layouts. Handling resizing beyond what is available to auto-resizing mask or smart loading subviews is more difficult to do from an outside controller.
I've created a custom image view that has a scroll view to see a long list of images in a three column display. It internally manages the images, so it only loads views for images that are seen on the screen.
Could you imagine having to build a UITableView by hand compositing the scroll view with cells, managing the queue of cell views, having to smart load the cells only when they would appear, and handling all the tap, swipe, and pan gestures every time you needed a screen with a tabular look?
I want the effect of a UISplitViewController however I am not using the split view template.
Is it relatively easy to achieve without the template? And with using normal UIViewController?
What I want it a customary sized and positioned UITableView which then has a customary sized detail view which then of course goes into a popover and detail view when portrait.
Doing it without Interface Builder, you would create a UIViewController class. In the viewDidLoad method of that class, create a UIView or a UITableView with the frame origin where you want it and a size that you want. (Release it in the viewDidUnload method.) Then set the UIViewController's self.view to point to this new view.
self.view = [[UIView alloc] initWithFrame:...]; // edit - added in response to your question
If you created a UIView, then you will want to put your UITableView inside this new view. (This approach lets you add more items to the container UIView if you need to.)
Make sure your UIViewController adheres to the UITableViewDelegate and UITableViewDataSource protocols. Add the delegate and datasource methods and you should be good to go.
This new view can cover other views, or you can size the other views to fit beside it. You only need to set there frames according to what you want to do with them.
There are some limitations if you use a UITableViewController, so a lot of people recommend using a UIViewController instead. like I described above. You can google for more info on that topic.
Just great a new temporary Xcode-project from that template and judge yourself, if it is complicated for you, to adept your (real) code.
Yes. You can do it quite easily. Just use delegates to pass messages between the left and the right side views (root and detail). For instance the didSelectRowAtIndexPath tableView method could be used along with delegation to pass a message to the right sided detail view. Tap a cell on the left table, show its text as a Label on the right side. Its just a simple example. And yes you can handle the rotations and send left side view into a UIPopoverController as well, thus giving the detail view full screen real estate in Portrait orientation.
Also try MGSplitViewController . It gives you a lot of other customization options on a split view controller.
I'm just not getting this, I want to display a view in my app when a user clicks a button.
I've gotten this far:
NSView* unitMarker = [[NSView alloc] initWithFrame: NSMakeRect( 20.0, 20.0, 80.0, 50.0 ) ];
How would I display this view with a red background?
Thanks
#Aaron: he says he wants to do this programmatically. Also he's using NSView, not UIView, so an iPhone tutorial would be almost irrelevant.
#Mike: Your description of what you want to do is a bit vague. We have a bit of code creating, a view, but no context to tell us exactly what you are trying to do. Do you want the view to come up in a new window or the same? Do you want to replace a view that's already there? We don't even really know your skill level.
I suggest you go check out the documentation for NSView: http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/ApplicationKit/Classes/NSView_Class/Reference/NSView.html
I've gotten this far:
NSView* unitMarker = [[NSView alloc] initWithFrame: NSMakeRect( 20.0, 20.0, 80.0, 50.0 ) ];
How would I display this view with a red background?
You wouldn't, because a plain NSView doesn't draw anything.
First, you need to subclass NSView, implement drawRect: in that subclass to fill its bounds with red, and instantiate that subclass instead of NSView directly.
You should read the View Programming Guide.
How would I display this view …
You wouldn't. The view displays itself when it is appropriate to do so.
It won't ever be appropriate for it to draw itself until you add it to a view hierarchy. Every window has one, rooted at its content view. You need to add this view either to a content view or to some descendant view (subview, subview of a subview, etc.) of a content view.
You normally should not tell a view to display from your controller. That's the window's job. When you do change a property or properties of the view that affect what it draws, set the view as needing display, and let the window tell the view to display when it's appropriate to do that.
Say this out loud 10 times repeatedly:
Interface Builder is my friend.
I was able to put together a sample project doing exactly what you want to do in about 5 minutes by leveraging Interface Builder as part of the process. http://www.markdouma.com/developer/ShowWindowWithRedView.zip.
You can't show a view without placing it in a window first; by far the easiest way to do this kind of a thing is to drag out a second window in Interface Builder, set it to not be visible on launch, drag a generic NSView custom view onto the Window, set its class to be SRRedView (your red view subclass). As d11wtq posted, you override NSView's primitive drawing method like he shows (though personally I prefer NSBezierPath :-P).
In your controller class, you define IBOutlets, and then hook those up in Interface Builder. These provide you with a way to reference the important parts of your interface so that you can manipulate them programmatically.
I added one IBAction method, which the button in the main window is hooked up to call. That method simply tells the second window to show itself.
- (IBAction)showWindowWithRedView:(id)sender {
[windowWithRedView makeKeyAndOrderFront:nil];
}
In the 8 years or more that I've been doing Cocoa programming, I don't think I've ever needed to resort to manually creating windows and views. It has always been much faster to simply load another nib file that contains the windows or views I need to display. Using Interface Builder along with Xcode to create your app is quite a bit different than how other IDEs work. (Specifically, when you arrange stuff in Interface Builder you're not generating code as much as you are creating instances of UI objects and then "freeze-drying" them in their current arrangement into a .nib archive file. When you launch the app, they are brought back to life. Or at least that's the way I think about it).
You need to subclass NSView and implement drawRect:.
In this case you're just going to fill the entire rect with red.
#interface MyView : NSView {
}
#end
#implementation MyView
-(void)drawRect:(NSRect)dirtyRect {
[[NSColor redColor] set];
NSRectFill(dirtyRect);
}
#end
That's an extremely basic example that does what you want, but if you want to do more complex things (adding borders (strokes) or drawing curves (paths) etc), then you need to learn all the drawing classes available to you.
Scott Stevenson has written some easy to follow tutorials on this:
http://cocoadevcentral.com/d/intro_to_quartz/ and;
http://cocoadevcentral.com/d/intro_to_quartz_two/