UIApplicationWillEnterForegroundNotification not called

Question

Hi I am very new in Iphone Development. I have a question :

I am using UIApplicationDeligate in my Appdeligate class and in this class i use two methods

applicationDidEnterBackground and applicationdisEnterForeGround. then these method works fine , when my app goes in background or in comes in foreground then flow goes inside these method.

But in another UiViewController class i attach listener for UIApplicationdidEnterForegroundNotification and UiApplicationdidEnterBackgroundNotification.

now when my app goes in background then flow goes in background method but when my app comes in foreground then app flow never comes in foreground method.

code which i am using in AppDelegate Class :

- (void)applicationDidEnterBackground:(UIApplication *)application
{

 NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:timertimetobefired forKey:@"TimerTimeToFired"];
[defaults setValue:timerrecipename forKey:@"TimerRecipeName"];
[defaults setObject:storingbuttonstate forKey:@"TimerButtonState"];



}

- (void)applicationWillEnterForeground:(UIApplication *)application
{

    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    timertimetobefired = [defaults objectForKey:@"TimerTimeToFired"];
    timerrecipename = [defaults objectForKey:@"TimerRecipeName"];
    storingbuttonstate = [defaults objectForKey:@"TimerButtonState"];


}

and code which i am using inside UiViewController class :

  [[NSNotificationCenter defaultCenter]
 addObserver:self
 selector:@selector(goBackground)
 name:UIApplicationDidEnterBackgroundNotification
 object:nil];


 [[NSNotificationCenter defaultCenter]
  addObserver:@"forground"
  selector:@selector(doMyLayoutStuff:)
  name: UIApplicationWillEnterForegroundNotification
  object:nil];



- (void) goBackground
{
if(timer != nil && [timer isValid])
{
 [timer invalidate], timer = nil;
}
}

can anyone tell me what wrong with this code . Thanks in advance.

code inside doMylayoutStuff :

- (void)doMyLayoutStuff:(id)sender
{

fortimer=0;
appdelegate.imgRecipePhoto=nil;
recipeMakingTime=0;
arrForStepsReminder=[[NSMutableArray alloc]init];
[arrForStepsReminder removeAllObjects];
arrForSteps5=[[NSMutableArray alloc]init];
[arrForSteps5 removeAllObjects];
arrForButtonSelection=[[NSMutableArray alloc]init];
[arrForButtonSelection removeAllObjects];

[arrForSteps5 addObjectsFromArray:appdelegate.arrStepsandTime];

arrayforshowingdata = [[NSMutableArray alloc]initWithCapacity:arrForSteps5.count];

for (int i=0; i<[arrForSteps5 count]; i++)
{
    //nitin tyagi. 6/08/2013.

    //        NSString *str12=[[arrForSteps5 objectAtIndex:i]objectForKey:@"RecipestepTime"];
    //        if (str12.length==0)
    //        {
    //            [arrForSteps5 removeObjectAtIndex:i];
    //        }
    //        else
    //        {
    //        }

    NSString *timer1 = [[arrForSteps5 objectAtIndex:i]objectForKey:@"RecipeTimer1"];
    NSString *timer2 = [[arrForSteps5 objectAtIndex:i]objectForKey:@"RecipeTimer2"];
    NSString *timer3 = [[arrForSteps5 objectAtIndex:i]objectForKey:@"RecipeTimer3"];
    NSString *timer4 = [[arrForSteps5 objectAtIndex:i]objectForKey:@"RecipeTimer4"];

    timer1 = [timer1 stringByReplacingOccurrencesOfString:@" " withString:@""];
    timer2 = [timer2 stringByReplacingOccurrencesOfString:@" " withString:@""];
    timer3 = [timer3 stringByReplacingOccurrencesOfString:@" " withString:@""];
    timer4 = [timer4 stringByReplacingOccurrencesOfString:@" " withString:@""];

    NSMutableArray *finaltimerarray = [[NSMutableArray alloc]init];


    int totalminute = 0;
    int hours = 0;

    if(([timer1 hasSuffix:@"mins"] || [timer1 hasSuffix:@"minute"] || [timer1 hasSuffix:@"min"]) || ([timer1 isEqualToString:@"0"]))
    {
        if(![timer1 isEqualToString:@"0"]){
            NSRange range = [timer1 rangeOfString:@"min"];
            NSString *minutes = [timer1 substringToIndex:range.location];
            totalminute = totalminute + [minutes intValue];

            NSNumber* xWrapped = [NSNumber numberWithInt:[minutes intValue]];
            [finaltimerarray addObject:xWrapped];
        }
        else
        {
            [finaltimerarray addObject:[NSNumber numberWithInt:0]];
        }

        // NSLog(@"totalminute minute is = %@",totalminute);
    }
    else if(([timer1 hasSuffix:@"hours"] || [timer1 hasSuffix:@"hrs"] || [timer1 hasSuffix:@"hour"] || [timer1 hasSuffix:@"hr"]) )
    {
        if(![timer1 isEqualToString:@"0"]){
            NSRange range = [timer1 rangeOfString:@"h"];
            NSString *hours = [timer1 substringToIndex:range.location];

            int minute = [hours intValue] * 60;
            totalminute = totalminute + minute;

            NSNumber* xWrapped = [NSNumber numberWithInt:minute];
            [finaltimerarray addObject:xWrapped];
        }
        else
        {
            [finaltimerarray addObject:[NSNumber numberWithInt:0]];
        }

        //  NSLog(@"timer1 minute is = %@",minutes);
    }
    if(([timer2 hasSuffix:@"mins"] || [timer2 hasSuffix:@"minute"] || [timer2 hasSuffix:@"min"]) || ([timer2 isEqualToString:@"0"]))
    {
        if(![timer2 isEqualToString:@"0"]){
            NSRange range = [timer2 rangeOfString:@"min"];
            NSString *minutes = [timer2 substringToIndex:range.location];

            totalminute = totalminute + [minutes intValue];

            NSNumber* xWrapped = [NSNumber numberWithInt:[minutes intValue]];
            [finaltimerarray addObject:xWrapped];
        }
        else
        {
            [finaltimerarray addObject:[NSNumber numberWithInt:0]];
        }

        // NSLog(@"timer2 minute is = %@",minutes);
    }

    else if(([timer2 hasSuffix:@"hours"] || [timer2 hasSuffix:@"hrs"] || [timer2 hasSuffix:@"hour"] || [timer2 hasSuffix:@"hr"]) )
    {
        if(![timer2 isEqualToString:@"0"])
        {
            NSRange range = [timer2 rangeOfString:@"h"];
            NSString *hours = [timer2 substringToIndex:range.location];
            int minute = [hours intValue] * 60;
            totalminute = totalminute + minute;

            NSNumber* xWrapped = [NSNumber numberWithInt:minute];
            [finaltimerarray addObject:xWrapped];
        }
        else
        {
            [finaltimerarray addObject:[NSNumber numberWithInt:0]];
        }

        //  NSLog(@"timer1 minute is = %@",minutes);
    }

    if(([timer3 hasSuffix:@"mins"] || [timer3 hasSuffix:@"minute"] || [timer3 hasSuffix:@"min"]) ||  ([timer3 isEqualToString:@"0"]))
    {
        if( ![timer3 isEqualToString:@"0"])
        {
            NSRange range = [timer3 rangeOfString:@"min"];
            NSString *minutes = [timer3 substringToIndex:range.location];
            totalminute = totalminute + [minutes intValue];

            NSNumber* xWrapped = [NSNumber numberWithInt:[minutes intValue]];
            [finaltimerarray addObject:xWrapped];
        }
        else
        {
            [finaltimerarray addObject:[NSNumber numberWithInt:0]];
        }

        // NSLog(@"timer3 minute is = %@",minutes);
    }
    else if(([timer3 hasSuffix:@"hours"] || [timer3 hasSuffix:@"hrs"] || [timer3 hasSuffix:@"hour"] || [timer3 hasSuffix:@"hr"]) )
    {
        if(![timer3 isEqualToString:@"0"]){
            NSRange range = [timer3 rangeOfString:@"h"];
            NSString *hours = [timer3 substringToIndex:range.location];
            int minute = [hours intValue] * 60;
            totalminute = totalminute + minute;

            NSNumber* xWrapped = [NSNumber numberWithInt:minute];
            [finaltimerarray addObject:xWrapped];
        }
        else
        {
            [finaltimerarray addObject:[NSNumber numberWithInt:0]];
        }
        //  NSLog(@"timer1 minute is = %@",minutes);
    }
    if(([timer4 hasSuffix:@"mins"] || [timer4 hasSuffix:@"minute"] || [timer4 hasSuffix:@"min"]) ||  ([timer4 isEqualToString:@"0"]))
    {
        if(![timer4 isEqualToString:@"0"])
        {
            NSRange range = [timer4 rangeOfString:@"min"];
            NSString *minutes = [timer4 substringToIndex:range.location];
            totalminute = totalminute + [minutes intValue];

            NSNumber* xWrapped = [NSNumber numberWithInt:[minutes intValue]];
            [finaltimerarray addObject:xWrapped];
        }
        else
        {
            [finaltimerarray addObject:[NSNumber numberWithInt:0]];
        }
        //  NSLog(@"timer4 minute is = %@",minutes);
    }
    else if(([timer4 hasSuffix:@"hours"] || [timer4 hasSuffix:@"hrs"] || [timer4 hasSuffix:@"hour"] || [timer4 hasSuffix:@"hr"]) )
    {
        if(![timer4 isEqualToString:@"0"]){
            NSRange range = [timer4 rangeOfString:@"h"];
            NSString *hours = [timer4 substringToIndex:range.location];
            int minute = [hours intValue] * 60;
            totalminute = totalminute + minute;

            NSNumber* xWrapped = [NSNumber numberWithInt:minute];
            [finaltimerarray addObject:xWrapped];
        }
        else
        {
            [finaltimerarray addObject:[NSNumber numberWithInt:0]];
        }

        //    NSLog(@"timer1 minute is = %@",minutes);
    }


    [arrayforshowingdata addObject:finaltimerarray];
    [finaltimerarray release];
}


for (int i=0; i<[arrayforshowingdata count]; i++)
{
    NSMutableArray *arraydata = [arrayforshowingdata objectAtIndex:i];

    for (int j=0; j<[arraydata count]; j++)
    {
        [arrForStepsReminder addObject:@"0"];
    }

    [arrForButtonSelection addObject:@"M"];
}

lblDisplayTimer.text=@"00:00:00";
lblRecipeName.text=appdelegate.strRecipeName;

currentdate = [NSDate date];
NSDate *timetobefired = appdelegate.timertimetobefired;
timerrecipe = appdelegate.timerrecipename;

if(timerrecipe != nil && ([timerrecipe isEqualToString:appdelegate.strRecipeName]) && timetobefired != nil)
{

    NSTimeInterval secondsBetween = [timetobefired timeIntervalSinceDate:currentdate];
    NSInteger time = round(secondsBetween);
    int second = (int)time;


    if(second > 0)
    {
        secondsLeft = second;
        arrForButtonSelection = appdelegate.storingbuttonstate;

        [btnOnOff setOn:YES];

        if(![timer isValid])
        {
            timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(updateCountdown) userInfo:nil repeats:YES];
        }
    }
    else
    {
        secondsLeft = 0;
    }
}

[[NSNotificationCenter defaultCenter]
 addObserver:self
 selector:@selector(goBackground)
 name:UIApplicationDidEnterBackgroundNotification
 object:nil];


 [[NSNotificationCenter defaultCenter]
  addObserver:self
  selector:@selector(doMyLayoutStuff:)
  name: UIApplicationWillEnterForegroundNotification
  object:nil];


}

Answer 1

Change the observer to "self" in your addObserver call

i.e

[[NSNotificationCenter defaultCenter]
  addObserver:self
  selector:@selector(doMyLayoutStuff:)
  name: UIApplicationWillEnterForegroundNotification
  object:nil];