Attendre [NSAlert beginSheetModalForWindow:...];

Nous avons créé un catégorie sur NSAlert pour lancer des alertes en mode synchrone, tout comme l'application des boîtes de dialogue modales:

NSInteger result;

//Run the alert as a sheet on the main window
result = [alert runModalSheet];

//Run the alert as a sheet on some other window
result = [alert runModalSheetForWindow:window];

Le code est disponible via GitHub, et la version actuelle affichée ci-dessous à des fins d'exhaustivité.

Fichier d'en-tête NSAlert+SynchronousSheet.h:

#import <Cocoa/Cocoa.h>


@interface NSAlert (SynchronousSheet)

-(NSInteger) runModalSheetForWindow:(NSWindow *)aWindow;
-(NSInteger) runModalSheet;

@end

Mise en œuvre de fichier NSAlert+SynchronousSheet.m:

#import "NSAlert+SynchronousSheet.h"
//Private methods -- use prefixes to avoid collisions with Apple's methods
@interface NSAlert ()
-(IBAction) BE_stopSynchronousSheet:(id)sender;   //hide sheet & stop modal
-(void) BE_beginSheetModalForWindow:(NSWindow *)aWindow;
@end
@implementation NSAlert (SynchronousSheet)
-(NSInteger) runModalSheetForWindow:(NSWindow *)aWindow {
//Set ourselves as the target for button clicks
for (NSButton *button in [self buttons]) {
[button setTarget:self];
[button setAction:@selector(BE_stopSynchronousSheet:)];
}
//Bring up the sheet and wait until stopSynchronousSheet is triggered by a button click
[self performSelectorOnMainThread:@selector(BE_beginSheetModalForWindow:) withObject:aWindow waitUntilDone:YES];
NSInteger modalCode = [NSApp runModalForWindow:[self window]];
//This is called only after stopSynchronousSheet is called (that is,
//one of the buttons is clicked)
[NSApp performSelectorOnMainThread:@selector(endSheet:) withObject:[self window] waitUntilDone:YES];
//Remove the sheet from the screen
[[self window] performSelectorOnMainThread:@selector(orderOut:) withObject:self waitUntilDone:YES];
return modalCode;
}
-(NSInteger) runModalSheet {
return [self runModalSheetForWindow:[NSApp mainWindow]];
}
#pragma mark Private methods
-(IBAction) BE_stopSynchronousSheet:(id)sender {
//See which of the buttons was clicked
NSUInteger clickedButtonIndex = [[self buttons] indexOfObject:sender];
//Be consistent with Apple's documentation (see NSAlert's addButtonWithTitle) so that
//the fourth button is numbered NSAlertThirdButtonReturn + 1, and so on
NSInteger modalCode = 0;
if (clickedButtonIndex == NSAlertFirstButtonReturn)
modalCode = NSAlertFirstButtonReturn;
else if (clickedButtonIndex == NSAlertSecondButtonReturn)
modalCode = NSAlertSecondButtonReturn;
else if (clickedButtonIndex == NSAlertThirdButtonReturn)
modalCode = NSAlertThirdButtonReturn;
else
modalCode = NSAlertThirdButtonReturn + (clickedButtonIndex - 2);
[NSApp stopModalWithCode:modalCode];
}
-(void) BE_beginSheetModalForWindow:(NSWindow *)aWindow {
[self beginSheetModalForWindow:aWindow modalDelegate:nil didEndSelector:nil contextInfo:nil];
}
@end

Ici est un NSAlert catégorie qui résout le problème (comme suggéré par Philipp avec la solution proposée par Frédéric et amélioré par Laurent P.: j'utilise un bloc de code au lieu d'un délégué, il est simplifié, encore une fois).

@implementation NSAlert (Cat)
-(NSInteger) runModalSheetForWindow:(NSWindow *)aWindow
{
[self beginSheetModalForWindow:aWindow completionHandler:^(NSModalResponse returnCode)
{ [NSApp stopModalWithCode:returnCode]; } ];
NSInteger modalCode = [NSApp runModalForWindow:[self window]];
return modalCode;
}
-(NSInteger) runModalSheet {
return [self runModalSheetForWindow:[NSApp mainWindow]];
}
@end

voici ma réponse:

Créer une variable de classe mondiale 'NSInteger alertReturnStatus'

- (void)alertDidEndSheet:(NSWindow *)sheet returnCode:(NSInteger)returnCode contextInfo:(void *)contextInfo
{
[[sheet window] orderOut:self];
//make the returnCode publicly available after closing the sheet
alertReturnStatus = returnCode;
}
- (BOOL)testSomething
{
if(2 != 3) {
//Init the return value
alertReturnStatus = -1;
NSAlert *alert = [[[NSAlert alloc] init] autorelease];
[alert addButtonWithTitle:@"OK"];
[alert addButtonWithTitle:@"Cancel"];
[alert setMessageText:NSLocalizedString(@"Warning", @"warning")];
[alert setInformativeText:@"Press OK for OK"];
[alert setAlertStyle:NSWarningAlertStyle];
[alert setShowsHelp:NO];
[alert setShowsSuppressionButton:NO];
[alert beginSheetModalForWindow:[self window] modalDelegate:self didEndSelector:@selector(alertDidEndSheet:returnCode:contextInfo:) contextInfo:nil];
//wait for the sheet
NSModalSession session = [NSApp beginModalSessionForWindow:[alert window]];
for (;;) {
//alertReturnStatus will be set in alertDidEndSheet:returnCode:contextInfo:
if(alertReturnStatus != -1)
break;
//Execute code on DefaultRunLoop
[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode 
beforeDate:[NSDate distantFuture]];
//Break the run loop if sheet was closed
if ([NSApp runModalSession:session] != NSRunContinuesResponse 
|| ![[alert window] isVisible]) 
break;
//Execute code on DefaultRunLoop
[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode 
beforeDate:[NSDate distantFuture]];
}
[NSApp endModalSession:session];
[NSApp endSheet:[alert window]];
//Check the returnCode by using the global variable alertReturnStatus
if(alertReturnStatus == NSAlertFirstButtonReturn) {
return YES;
}
return NO;
}
return YES;
}

Espère que ça vous aidera,
Cheers
--Hans

Contrairement à Windows je ne crois pas qu'il y a un moyen de bloquer sur des boîtes de dialogue modales. L'entrée (par exemple à l'utilisateur de cliquer sur un bouton) seront traitées sur votre thread principal donc il n'y a aucun moyen de blocage.

Pour votre tâche vous devrez passer le message en haut de la pile puis de la reprendre là où vous l'avez laissé.

- (bool) windowShouldClose: (id) sender
{//printf("windowShouldClose..........\n");
NSAlert *alert=[[NSAlert alloc ]init];
[alert setMessageText:@"save file before closing?"];
[alert setInformativeText:@"voorkom verlies van laatste wijzigingen"];
[alert addButtonWithTitle:@"save"];
[alert addButtonWithTitle:@"Quit"];
[alert addButtonWithTitle:@"cancel"];
[alert beginSheetModalForWindow: _window modalDelegate: self
didEndSelector: @selector(alertDidEnd: returnCode: contextInfo:)
contextInfo: nil];
return false;
}