How to get number of days between two dates object

问题:

This question already has answers here:

How can I compare two dates, return a number of days (4 answers)

Objective C - calculating the number of days between two dates (6 answers)

Closed 6 years ago.

I'm trying to make a label that says how many days left till event. I want to calculate the difference between todays date and the events date. I'm using this code and its giving me -4600. It works fine till I use todays date.

NSDateFormatter *f = [[NSDateFormatter alloc] init];
    [f setDateFormat:@"yyyy-MM-dd"];
    NSDate *startDate = [NSDate date];
    NSDate *endDate = [f dateFromString:end];
    NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDateComponents *components = [gregorianCalendar components:NSDayCalendarUnit
                                                        fromDate:startDate
                                                          toDate:endDate
                                                         options:0];
    return components.day;
return components.day;

回答1:

By default [NSDate date] return date in like 2013-08-06 08:50:25 +0000 and you have set your formatter to yyyy-MM-dd this, so you have to convert your startDate to yyyy-MM-dd this form..

Try this

NSDateFormatter *f = [[NSDateFormatter alloc] init];
    [f setDateFormat:@"yyyy-MM-ddHH:mm:ss ZZZ"];
    NSDate *startDate = [NSDate date];
    NSLog(@"%@",startDate);
    NSDate *endDate = [f dateFromString:end];
    NSLog(@"%@",endDate);


    NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDateComponents *components = [gregorianCalendar components:NSDayCalendarUnit
                                                        fromDate:startDate
                                                          toDate:endDate
                                                         options:0];
    return components.day;