On Jan 26, 2011, at 5:29 PM, Luca Tarozzi wrote: > I am new to cocoa and objective C.
Hi and welcome to Cocoa! I'm sure you'll have fun! The learning curve at the start is a bit steep, but don't worry, it'll get easier after a while :-) > I am looking for a way to handle events for a NSView created > programmatically (without IB). Sure. There's lots of good documentation on views on Apple's developer site <http://developer.apple.com>. The thing to keep in mind when creating views programmatically is that they're just normal objects, so you just create them, use addView to insert them in the hierarchy on the screen (e.g. into a window's contentView). But honestly, this is an odd thing to want to do as your first Cocoa project. What are you trying to create where you need to create a view in code? Usually just dropping views in a NIB and using an NSViewController to load that, then inserting the view(s) loaded like that into whatever parent view is a more common approach. You can even create several instances of the same view controller class, thus giving you several copies of the object in one NIB. > Is it possible starting from the following code? > > - (void)applicationDidFinishLaunching:(NSNotification *)aNotification { > > // Insert code here to initialize your application > > // [[NSColor yellowColor] set]; Where will that color go? You're not in drawRect:, so you probably don't have a drawing context to draw into. > NSView *superView = [window contentView]; > > // [NSBezierPath fillRect:[superView bounds]]; > > NSRect frame = NSMakeRect(50, 50, 200, 100); > > NSView *myView = [[NSView alloc] initWithFrame:frame]; > > [superView addSubview:myView]; Okay, creating a view here and inserting it in the window's superview, perfectly fine code that does what you said you wanted to do. But why create a plain NSView? Plain NSViews are usually either used as a base class for your own custom views, or as containers to group together other views invisibly (e.g. so you can easily hide several views as once). > [[NSColor greenColor] set]; > > [NSBezierPath fillRect:[myView bounds]]; Again, unmotivated drawing code hanging in mid-air. Is this supposed to be shown in the view? Views aren't just canvases to draw in. Look at the view programming guide Apple has to see how to create your own NSView subclasses and draw custom stuff in them. If you just want to show a little decorational image, look at NSImage and NSImageView. If it's anything more complex (like a graph, or something that has clickable parts), NSView subclass is probably the place to go. > [myView setTarget:self] 1) Missing semicolon 2) A target without an action is kind of pointless 3) NSView doesn't have a setTarget: method, nor a setAction: method. If you implement your own NSView subclass, you can implement your own target/action methods (just a SEL and an id property, and then use -performSelector:withObject: inherited from NSObject). Otherwise, create another class that has such a property, e.g. an NSButton, NSTextField or other NSControl subclass are generally good candidates. > // [myView setNeedsDisplay:YES]; > > [myView release]; Thanks for putting the "release" in there. Always good to see you've taken the time to read the memory management rules :-) Many people don't bother memorizing the rules on Apple's web site (http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/MemoryMgmt/Articles/mmRules.html) and then muddle around and keep crashing because they free objects owned by others etc. Cheers, -- Uli Kusterer "The Witnesses of TeachText are everywhere..." http://www.masters-of-the-void.com _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
