If you build a custom UIView, and integrate it inside of a parent view/view controller in interface builder, the graphical element representing your custom view is invisible, if you don't specify a background color (I don't).
Is there any way, solely during development, to identify different custom views? Any hacks/tricks to distinguish them?
The closest I could come up with is setting the background color in IB, then removing the background in the implementation of the custom view.
Bounds Rectangles
You might find bounds rectangles useful. You can turn them on by going to the menu bar and choosing Editor > Canvas > Show Bounds Rectangles.
Here's an example. I have a view (a UICollectionViewCell subclass) laid out in a nib. It has a single-line label, a two-line label, and a custom subview. The custom subview itself contains a smaller custom subview. Here's the nib with bounds rectangles off:
Here's the same nib with bounds rectangles on:
Background Color Override
Here's another technique that builds on the idea of setting the background color. This technique requires your deployment target to be iOS 5.0 or later.
As you described, set the background color to make the view visible in the nib:
Then switch to the Identity Inspector and add backgroundColor in the User Defined Runtime Attributes section. Set it to the background color you want the view to have at runtime. For example, if you want it to be white at runtime:
If you want the background color to be clear, you can set backgroundColor to a color with opacity 0, or you can set it to “Nil” instead of any color:
That approach of setting the background color in Interface Builder, but resetting it in code is a simple, but effective technique. Two refinements:
If you have multiple custom views on a single storyboard scene, you can save yourself from having to programmatically clear the background color for all of them individually by using IBOutletCollection. So, in Interface Builder, give them all background colors and then add all of your custom views for a given scene to a collection. You then can set the background color for all of them in a single statement. So, for example, if you have a dozen controls on one scene all in a single IBOutletCollection is named viewsCollection:
#property (strong, nonatomic) IBOutletCollection(UIView) NSArray *viewsCollection;
you can clear the background color of all of them in a single statement:
[self.viewsCollection setValue:[UIColor clearColor] forKey:#"backgroundColor"];
You can also make the identification of your custom views in Interface Builder a little easier by setting the "Label" in the "Document" properties on the "Identity inspector":
Once you've done that, when you look at the document outline in the left side of the main panel, you'll see your labels show up:
Then, using the document outline makes it easier to identify your individual views in the scene. You can use a random label like I did here, or you could use the name of your custom view class, or whatever.
Related
I have always wondered if there is a way to add custom "snap lines" to a UIView descendant, so I have a nice mechanism to layout my views using the Interface Builder of Xcode.
Here is my very basic UIView:
This view serves as a container control for other UIViews. Is there a way to add these lines so Xcode draws the "blue snap" lines when moving a control inside this view?
I know that there are UILayoutGuides but these don't add the desired snap lines to the Interface Builder (Xcode 9.3).
Here is another screenshot:
A workaround for this would be creating a view with a height of 1 and the width of its superview. After that, views with the same superview will snap to it.
Some tips:
Set a light background color for the view, so that it won't be distracting.
Remove the view when it's no longer needed. If you want to keep it for later usage, just hide it.
I'm writing an OS X app and have a problem with font smoothing in separate window.
I have a text field where you put text and suggestion window which pops up with a list of suggestions according to what you wrote. I'm using View-cell based NSTableView to display those suggestions and SFBPopoverWindowController to display it as a "popup" window (tried other classes with the same effect). When rows are first drawn they look fine but after I select them (keyboard or mouse) the font changes it's weight. It's only visual - like you would change smoothing method on the font, not it's bold setting.
"Music note" is the selected cell here
What's even more strange is that after I hide and show the window 3 times everything works fine from that point on.
Again - "Music note" is the selected cell.
The selection is done by overwriting NSTableRowView class and its drawSelectionInRect: method but I tried with drawing everything inside custom NSTableCellView class and it didn't help. The text is standard NSTextField - nothing's changed there.
The SFBPopoverWindow (and it's controller) are created once and reused with styleMask NSBorderlessWindowMask, backing NSBackingStoreBuffered, defer set to YES. The only change in SFBPopoverWindowController I made was to turn off window becoming key window but it doesn't change anything.
It might be related to the way a table view draws it's selected cells (setSelectionHightLightStyle:). Try to set the style to None/ NSTableViewSelectionHighlightStyleNone in your code or IB / Storyboard-file and draw the selection yourself (in a NSTableRowView subclass).
Background: When you use NSTableViewSelectionHighlightStyleRegular or NSTableViewSelectionHighlightStyleSourceList the table view assumes that you use the standard selection behaviour and appearance and does some magic to support that.
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UPDATE
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My previous answer is still valid but since it only describes the problem and hints at a workaround, I wanted to add a real solution. If you want to use NSTableViewSelectionHighlightStyleRegular for your table view (with custom font and colors), you need a way to 'disable' the system magic that comes into place once your row is highlighted. One proposed solution is to decline the first responder status. It has a lot of drawbacks and isn't a good solution at all.
So, let's have a closer look at the system 'magic' that kicks in as soon as the row will be highlighted: NSTableRowView has a property interiorBackgroundStyle that is – according to the documentation – 'an indication of how the subviews should draw'. Furthermore 'This value is dynamically computed based on the set of properties set for the NSTableRowView. Subclassers can override this value when they draw differently based on the currently displayed properties. This method can also be called to determine what color a subview should use, or alternatively, NSControls can have the -backgroundStyle set on their cell to this value.'
I assume that this style will be handed down the subview hierarchy and causes your text fields to look odd. The system assumes that a highlighted cell has a dark background and changes the interiorBackgroundStyle to dark. Other controls try to adapt accordingly.
I think there are two solutions to this problem:
1) Override interiorBackgroundStyle in your NSTableRowView subclass and return the style that fits your interface (in my case it's .light because my highlight color is a very bright blue). This worked for me.
2) If changing the whole style is a bit too much because you only want certain elements to not change their style, you may only need to adjust these subclasses. I haven't tried this yet.
I'm trying to get NSClipView to either draw a clear background (set the color to clear results in a black box), or no background at all. Drawing no background results in ghosting artifacts. Anyway to get this to draw no background without the artifacts???
The NSClipView is contained inside an NSBox subclass. An NSTextView is contained inside the NSClipView. It's basically an attempt at rolling my own NSTextField. I need to be able to draw a custom background and included subviews such as buttons.
The trails behavior is noted in the documentation of NSClipView. If the clip view is contained in a NSScrollView the documentation suggests calling setDrawsBackground: on the scroll view instead.
You could also try setting the background color of the scroll view to the clear color, assuming that the clip view is in a scroll view.
If the clip view is not in a scroll view then you might want to explain what the view hierarchy is like, and any code relavent to its construction.
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....
Is there a simple way to create a selectable NSRect in Cocoa? In need a rectangle that can be selected and stays selected after a mouse click.
Thanks.
NSRect is just a struct with a position and size. It's not an object that can actually do anything or have any properties other than a width and height. It sounds like what you want is to create an NSView that can be selected. (Here's Apple's Guide on the subject.)
Though not as immediate as you would like, you may be interested in the management of tracking rectangles and tracking areas performed by NSView class.
This mechanism allows you to define specific areas of your custom view. Then, an event is generated whenever the cursor enters or leaves the area, or a mouse button is pressed in this area (-mouseEntered:, -mouseExited:, -mouseDown:, -mouseUp:, -mouseDragged:, ... of NSResponder class). This up to you to define what you want your application do in response to these events (set the rectangle as selected and display it accordingly).
For an example implementation of this, take a look at the Sketch example included with the Apple developer tools (look in /Developer/Examples/AppKit). Sketch allows the user to create new graphics (including rectangles, but also ovals, lines, and text), select them, move them around in the document, etc. In particular, you'll probably want to look at the SKTGraphic class, which represents a single graphic object in the document, and the SKTGraphicView class, which is an NSView subclass that perform the actual layout and drawing, handling mouse events for dragging views around, etc.