ARC通过C ++抽象层进行的Objective-C委派

Question

I'm programming simple cross platform C++ layer (dylib) that gets implemented by Objective-C. The parts that are platform specific are included through platform macros.

The NSUserNotificationCenter requires the delegation pattern for handling specific actions, clicking on the notification for example. The issue I'm facing is that as soon as I execute send , the notification is sent but the instance unloads right after that. Thus the onclick notification action never gets called (didActivateNotification) instead it crashes for a bad pointer. How can I make this work?

Note: SomeObjectiveC.mm is a class located in my Application. AppleUserNotificationManager.m is initialized by NotificationManager+apple.mm and both are located in my Dylib.

SomeObjectiveC.mm

Notification *notification = new Notification;
notification->setTitle("Foo bar notification");
notification->setMessage("Hello world!");

NotificationManager *notificationManager = new NotificationManager;
notificationManager->send(notification);

NotificationManager+apple.mm

#include "notificationManager+apple.hpp"

bool NotificationManager::send(Notification *notification)
{
    AppleUserNotificationManager *notificationManager = [[AppleUserNotificationManager alloc] init];

    NSString *title = [NSString stringWithUTF8String:notification->getTitle().c_str()];
    NSString *message = [NSString stringWithUTF8String:notification->getMessage().c_str()];
    if (notification->getSoundName().empty()) {
        [notificationManager sendWithTitle:title andMessage:message];
    }

    NSString *soundName = [NSString stringWithUTF8String:notification->getSoundName().c_str()];
    [notificationManager sendWithTitle:title andMessage:message andSound: soundName];

    return true;
}

AppleUserNotificationManager.m

#import "AppleUserNotificationManager.h"

@implementation AppleUserNotificationManager

@synthesize userNotification;

- (id)init
{
    [[NSUserNotificationCenter defaultUserNotificationCenter] setDelegate: self];
    userNotification = [[NSUserNotification alloc] init];

    self = [super init];
    return self;
}

/**
 *  @param NSUserNotificationCenter center
 *  @param NSUserNotification notification
 *
 *  @return bool
 */
- (BOOL)userNotificationCenter:(NSUserNotificationCenter *)center shouldPresentNotification:(NSUserNotification *)notification{
    return YES;
}

/**
 *  @param NSUserNotificationCenter center
 *  @param NSUserNotification notification
 */
- (void) userNotificationCenter:(NSUserNotificationCenter *)center didActivateNotification:(NSUserNotification *)notification
{
    NSString *notificationText = [notification informativeText];
    NSString *urlRegEx = @"(http|https)://((\\w)*|([0-9]*)|([-|_])*)+([\\.|/]((\\w)*|([0-9]*)|([-|_])*))+";

    NSPredicate *urlTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", urlRegEx];
    if ([urlTest evaluateWithObject:notificationText]) {
        [[NSWorkspace sharedWorkspace] openURL:[NSURL URLWithString:notificationText]];
    }
}

/**
 * @param NSString title
 * @param NSString message
 * @param NSString soundName
 */
- (void)sendWithTitle:(NSString *)title andMessage:(NSString *)message andSound:(NSString *)soundName{
    userNotification.title = title;
    userNotification.informativeText = message;
    userNotification.soundName = soundName;

    [[NSUserNotificationCenter defaultUserNotificationCenter] deliverNotification: userNotification];
}

@end

Answer 1

Used self pointer before allocated?
Could below change fix the problem?

- (id)init
{
    self = [super init];

    [[NSUserNotificationCenter defaultUserNotificationCenter] setDelegate: self];
    userNotification = [[NSUserNotification alloc] init];

    return self;
}