Calling SetNeedsDisplay from other class - objective-c

Question

Today I'm facing a new problem:
I have a ViewController (Subclass of NSView) and another class (Subclass of NSObject) which, through an IBAction, try to call back the viewController to redraw its view using SetNeedsDisplay:YES.
The method to redraw the view (ViewController.m) is:
- (void) redrawView {
[self setNeedsDisplay:YES]
}
// With an NSLog i see that the method is called !
// Instead of self i tried even an outlet connected to the custom view.
}
What I'm doing to call the ViewController method through my other class is:
1) #import "ViewController.h"
2) into the IBAction i made a new istance of ViewController as:
ViewController *newIstanceOfViewController = [[ViewController alloc] init]
3) [newIstanceOfViewController redrawView]
The log show me that setNeedsDisplay is called but drawrect no ! Why ? I have forgotten to init or subview something ? Thanks
THE ORIGINAL CODE HERE (DIFFERENT NAME OF METHODS DUE TO LANGUAGE, SAME SYNTAX)
// Controller.h
#import <Cocoa/Cocoa.h>
#interface Controller : NSView {
IBOutlet NSView *tastierinoView;
}
- (void) aggiornaTastierinoView;
#end
// Controller.m
#import "Controller.h"
#implementation Controller
//Contatore numero volte disegno view
int contatore = 0;
- (id)initWithFrame:(NSRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code here.
tastierinoView = [[NSView alloc] init];
}
return self;
}
- (void) aggiornaTastierinoView { //THIS IS THE METHOD TO CALL REDRAW
[tastierinoView setNeedsDisplay:YES];
NSLog(#"Chiamo setneedsDisplay\n\n");
}
- (void)drawRect:(NSRect)dirtyRect
{
contatore++;
NSLog(#"La view è stata disegnata %d volte\n\n",contatore);
[super drawRect:dirtyRect];
// Drawing code here.
NSBezierPath* percorso = [NSBezierPath bezierPath];
[[NSColor cyanColor] set];
[percorso moveToPoint:NSMakePoint(150, 150)];
[percorso lineToPoint:NSMakePoint(250, 150)];
[percorso setLineWidth:5.0];
[percorso stroke];
}
#end
// ManipolatorePin.h
#import <Foundation/Foundation.h>
#interface ManipolatorePin : NSObject {
IBOutlet NSWindow *finestraPrincipaleWindow;
IBOutlet NSTextField *codiceTextField;
NSArray *coordinate_x;
NSArray *coordinate_y;
//L'array sotto riportato serve, tramite un ciclo for, a salvare il codice pin spezzato in singoli numeri che corrisponderanno al punto.
NSMutableArray *numeroAllaIndexArray;
}
- (IBAction)aggiornaTastierino:(id)sender;
#end
// ManipolatorePin.m
#import "ManipolatorePin.h"
#import "Controller.h"
#implementation ManipolatorePin
- (void)awakeFromNib {
coordinate_x = [[NSArray alloc] initWithObjects:#"150",#"50",#"150",#"250",#"50",#"150",#"250",#"50",#"150",#"250", nil];
coordinate_y = [[NSArray alloc] initWithObjects:#"50",#"150",#"150",#"150",#"250",#"250",#"250",#"350",#"350",#"350", nil];
numeroAllaIndexArray = [[NSMutableArray alloc] init];
NSLog(#"Array coordinate iniziallizato.\nTest:(%#) -> deve risultare \"50\"\n\n",[coordinate_x objectAtIndex:4]);
}
- (IBAction)aggiornaTastierino:(id)sender {
NSString *codiceString = [[NSString alloc] initWithFormat:[NSString stringWithFormat:#"%#",[codiceTextField stringValue]]];
NSLog(#"codiceTextField = %#", codiceString);
int lunghezzaCodiceString;
NSLog(#"Il codice risulta essere composto da (%d) numeri\n\n",[codiceString length]);
//Svuoto array
[numeroAllaIndexArray removeAllObjects];
for (lunghezzaCodiceString = 0; lunghezzaCodiceString < [codiceString length]; lunghezzaCodiceString++) {
//Compilo array (Ci provo ahah)
NSString *carattereDelCodiceStringInEsame = [[NSString alloc] init];
carattereDelCodiceStringInEsame = [codiceString substringWithRange:NSMakeRange(lunghezzaCodiceString,1)];
NSLog(#"Aggiungo il numero (%#) all'array 'numeroAllaIndexArray'",carattereDelCodiceStringInEsame);
[numeroAllaIndexArray addObject:carattereDelCodiceStringInEsame];
}
//DEBUG - DA QUI IN POI E' CANCELLABILE
NSLog(#"\n\nCiclo for termitato\nProcesso concluso con successo\n\n\nContenuto array:");
int conteggioArray;
for (conteggioArray = 0; conteggioArray < [numeroAllaIndexArray count] ; conteggioArray++ ) {
NSLog(#"index (%d) -> (%#)",conteggioArray,[numeroAllaIndexArray objectAtIndex:conteggioArray]);
NSLog(#"\n\n");
}
//FINE DEBUG
///////////////HERE THE INSTANCE TO CALL THE CONTROLLER
Controller *istanzaGestionaleController = [[Controller alloc] init];
[istanzaGestionaleController aggiornaTastierinoView];
}
#end

Answer 1

It sounds like you have two unrelated instances of ViewController. You need to call redrawView on the instance that actually has a view on the screen.
In your class (which is not the NSViewController), create a property like this:
#property (nonatomic, readwrite, weak) NSViewController *vc;
When the class is instantiated:
YourClass *yourInstance = [[YourClass alloc] init];
assign the value of vc:
yourInstance.vc = self; // self is your NSViewController instance
Then when you want to trigger a redraw, you pass the command to self.vc inside your other class.