Cocoa: Multiple windows COSC346

Transcription

1 Cocoa: Multiple s COSC346

2 Window controller The behaviour of each is controlled by an NSWindowController object To create a new, create a new class that extends (abstract) NSWindowController When creating new Cocoa Class in Xcode, if you indicate that you are extending NSWindowController, Xcode will provide you with an option to create a new XIB file 2

3 NSWindowController NSWindowController object contains methods for loading and closing of the associated let newwincontrl = NSWindowController(NibName:"NibName") newwincontrl.showwindow(self) To create a new, you allocate a new instance of NSWindowController (or its subclass) and associate it with a NIB file Window method of NSWindowController returns reference to the NSWindow object associated with the controller 3

4 Custom Controller It is common to create a custom controller that extends NSWindowController You can override certain methods to customise controller behaviour WillLoad invoked just before is loaded DidLoad invoked after is loaded It is common to implement the delegate methods in this custom controller, and make the controller the s delegate When building a single- application, the abstraction that NSWindowController provides is less important 4

5 Application ( controller) NSWindowController NibName:NSString wctr NSWindow contentview Controller NSView NIB File subivews[0] subivews[1] NSSlider Model View 5

6 Application ( delegate) NSWindowController NibName:NSString wctr NSWindow Window Delegate delegate contentview Controller NSView NIB File subivews[0] subivews[1] NSSlider Model View 6

7 File s owner and NIB files The process of loading a NIB file (to load a ) is trigged by an object That object is the file s owner referring to ownership of the NIB file Class of file s owner is stored in the NIB file: used as a proxy to load other elements on init. The file s owner, or its delegate, can store outlets to the elements in the Trouble creating an outlet? Check if class where you re placing outlet is file s owner for XIB file 7

8 File s owner single/multi- In a single- application, file s owner for main is the NSApplication Pre Xcode 8.3, a single- application set up the AppDelegate to be the file s owner In a multi- application, you need a file s owner that will have a new object instance for each new NSApplication is a singleton, so it cannot be a file s owner for multiple s NSWindowController is often chosen to be the file s owner for s loaded at run-time 8

9 Application (multi-) NSWindowController NSWindowController NibName:NSString NibName:NSString wctr wctr NSWindow NSWindow winctrl[1] winctrl[0] App Delegate Controller contentview contentview NSView NSView NIB File subivews[0] subivews[0] subivews[1] subivews[1] NSSlider NSSlider Model View 9

10 NSViewController Library style applications may need to load and manage views in a dynamically NSViewController is used to manage multiple views Has methods for runtime load / display of views Storyboard-based GUI design in Xcode provides an NSViewController as default starting point for IBOutlets and IBActions 10

11 Other s NSPanel NSPanel is a subclass of NSWindow It is a special type of that functions as an auxiliary to an existing Cannot be the main Lightweight: typically not released upon closing, as it is used often Example: the open file or save file panel 11

12 Other s dialog(ue) box Alerts are modal s: demand user attention Are you sure you want to erase your hard drive? Good UI design tries to minimise alerts Alerts are easy to create let choice = NSAlert() choice.messagetext = "Title" choice.informativetext = "Message" choice.alertstyle = NSAlertStyle.warning choice.addbutton(withtitle: "OK") choice.addbutton(withtitle: "Cancel") switch(choice.runmodal()){ case NSAlertFirstButtonReturn: print("ok button") case NSAlertSecondButtonReturn: print("cancel button") default: print("another button?!?") } NB: I d not actually format switch statements like this! It's just so that they fit on the slide better... 12

13 Summary In the last two lectures we covered the s and view hierarchy that constitute the fundamental aspects of Cocoa s GUI. We have also introduced controllers and delegates that manage the run-time behaviour of multi- applications. NSWindow class controlling the display aspects of a NSWindowDelegate protocol for s delegate, which reacts to events NSView draws content in a rectangular area, coordinates, geometric operations NSWindowController controls runtime resources NSViewController (optional) controls runtime view resources 13

14 Timer App NSMenuItem startmenuitem action:selector = startstopaction NSTimer msg:selector = countup seconds:int running:bool resetaction(sender) validatemenuitem():bool countup() Controller Model stopmenuitem resetbutton timerdisplay startstopbutton NSMenuItem action:selector = startstopaction NSTextField stringvalue:string action:selector = startstopaction enabled:bool title:string action:selector = resetaction enabled:bool 14 View

15 Timer App MVC startmenuitem stopmenuitem NSMenuItem action:selector = startstopaction NSMenuItem action:selector = startstopaction start() stop() reset() TimerModel seconds:int stopping:bool running:bool timer delegate resetaction(sender) validatemenuitem():bool secondschanged(int) Controller timerdisplay startstopbutton NSTextField stringvalue:string action:selector = startstopaction enabled:bool title:string NSTimer msg:selector = countup resetbutton action:selector = resetaction enabled:bool Model View

16 Timer multi- AppDelegate newtimerwindow(sender) startmenuitem stopmenuitem menuitemnew NSMenuItem startstopaction NSMenuItem startstopaction NSMenuItem newtimerwindow MainMenu.xib Model timerwindows[0] NSWindow contentview NSView start() stop() reset() TimerModel seconds:int stopping:bool running:bool NSTimer msg:selector = countup timer delegate resetaction(sender) secondschanged(int) Controller startstopbutton resetbutton timerdisplay NSTextField stringvalue:string action:selector = startstopaction enabled:bool title:string View action:selector = resetaction enabled:bool subviews[0] subviews[1] View subviews[2] 16 TimerWindowController.xib