ios - Trying to use NSDate for time only -

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i'm struggling find way use nsdate time purposes. trying following code:

- (void)awakefrominsert {     nsdatecomponents *comps = [[nsdatecomponents alloc] init];     comps.minute = 45;     comps.second = 0;      nscalendar *calendar = [[nscalendar alloc] initwithcalendaridentifier:nsgregoriancalendar];     self.periodduration = [calendar datefromcomponents:comps];     nslog(@"periodduration: %@",self.periodduration);      comps = [[nsdatecomponents alloc] init];     comps.hour = 8;     comps.minute = 0;     self.firstperiodstarttime = [calendar datefromcomponents:comps];     nslog(@"firstperiodtime: %@",self.periodduration); }

but result is:

periodduration: 0001-12-31 22:24:04 +0000 firstperiodtime: 0001-12-31 22:24:04 +0000

the result expecting:

periodduration: 45:00 firstperiodtime: 08:00

what doing wrong? how can fix this? thank you.

the log of date misleading you, if forming date few components not proper date instance uniquely identifies date , time.

if try code snipped can find if converting dates string expect

nsdatecomponents *comps = [[nsdatecomponents alloc] init]; comps.minute = 45; comps.second = 0;  nscalendar *calendar = [nscalendar currentcalendar]; nsdate *perioddate = [calendar datefromcomponents:comps]; nsdateformatter *dateformatter = [[nsdateformatter alloc] init]; [dateformatter setdateformat:@"mm:ss"]; nslog(@"periodduration: %@",[dateformatter stringfromdate:perioddate]);  comps = [[nsdatecomponents alloc] init]; comps.hour = 8; comps.minute = 0; nsdate *firstperioddate = [calendar datefromcomponents:comps]; [dateformatter setdateformat:@"hh:mm"]; nslog(@"firstperiodtime: %@",[dateformatter stringfromdate:firstperioddate]);

periodduration: 45:00

firstperiodtime: 08:00


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