ios - How do I send the a String to AppDelegate in Objective-C? -

i've create class 'datetool' inherit nsobject record date when application launched. need show starttime string in appdelegate.

i tried use block send string variable declared in 'appdelegate.h', however, couldn't in datetool's method initialize.

datetool.m

static nsstring *starttime2;  +(void)initialize {     if (self == [datetool self])    {         nsdateformatter *formatter = [[nsdateformatter alloc] init];        [formatter setdatestyle:nsdateformatternostyle];        [formatter settimestyle:nsdateformattermediumstyle];        starttime2 = [formatter stringfromdate:[nsdate date]];     } } 

i suggest provide delegate protocol in datetool implemented appdelegate. example (not tested):

datetool.h:

/** delegate protocol of datetool. */  @protocol datetooldelegate <nsobject>  /** start date set. */ - (void)startdateset:(nsdate)startdate;  @end  @interface datetool : nsobject  /** delegate of datetool. */ @property (weak) id<datetooldelegate> delegate;  @end 

datetool.m:

+(void)initialize {     if (self == [datetool self])    {         nsdateformatter *formatter = [[nsdateformatter alloc] init];        [formatter setdatestyle:nsdateformatternostyle];        [formatter settimestyle:nsdateformattermediumstyle];        starttime2 = [formatter stringfromdate:[nsdate date]];        if ([_delegate conformstoprotocol:@protocol(datetooldelegate)]) {            [_delegate startdateset:starttime2];        }     } } 

in appdelegate.h need add protocol:

#import "datetool.h" @interface appdelegate : uiresponder <datetooldelegate> 

in appdelegate.m need register delegate:

...     datetool.delegate = self; ... 

and implement protocol:

- (void)startdateset:(nsdate)startdate { // startdate } 

hope helps.

ps: why initialize class method? i'd suggest instantiate object.