how to create a countdown for a date given in a different view?

Question

Hey I have an initial screen that comes up when the app is launched the first time or when edit button is clicked, I will be taking a target date from the user using a date picker.
How can I then do a countdown on the home screen to this given date??
Please help!

Answer 1

Add NSTimer and use this two variables NSTimeInterval start = [[NSDate date] timeIntervalSince1970]; NSTimeInterval end = [selectedDate timeIntervalSince1970];

Answer 2

You could use timeIntervalSince like this;

NSDate *chosenDate;

// Time interval between future date and todays date
NSTimeInterval *intervalInSeconds = [chosenDate timeIntervalSinceDate:[NSDate Date]];

Then you convert it to the units of your choice like this;

How can I calculate the difference between two dates?

Answer 3

It sounds like are asking asking about how to share a property between screens. There are a couple approaches to this.

1. Put the date property in your appDelegate
2. Give your initial screen a reference to the home screen
3. Give your home screen a reference to the initial screen
4. Create a singleton that manages data for you.