Dates in app inventor

[Ariel Flaks]

Hi friends, I have a problem, and I can´t solve it

I have two dates, one from the datepicker and one from the current date, what I want to do is to have the diferences in days from one date to other.

I made the blocks and it work, but for some dates i goes wrong, for eg. today is 6/3/2017 and pick the date 11/03/2017 and it work.. but if I pick 15/3/2017 I have worng answer...356 days!!!.

What do you think that I am doing wrong?

thanks

[Taifun]

see the documentation and define fecha_fut accordingly

http://ai2.appinventor.mit.edu/reference/components/sensors.html#Clock

InstantInTime MakeInstant(text from)

Returns an instant specified by MM/DD/YYYY hh:mm:ss or MM/DD/YYYY or hh:mm. An example text input is "06/22/2015 12:18"

also you could simplify a little bit, see screenshot...

and: use Do it to debug your blocks, see tip 4 here

Top 5 Tips: How to learn App Inventor

Taifun

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Trying to push the limits of App Inventor! Snippets, Tutorials and Extensions from Pura Vida Apps by Taifun. 

[Ariel Flaks]

Thanks Taifun for your help, I don´t undestand where is the problem.... I define the variable as dd/MM/YYYY

Also, I simplify as you recommend : 

But still not workin ..

Thanks again

Ariel

[Taifun]

if you take a look at the documentation, you will realize, that the MakeInstant method needs the format MM/DD/YYYY  and NOT DD/MM/YYYY

Taifun

[Abraham Getzler]

15/3/2017 is the third of Marchtember,  the 15th month of 2017.

ABG

[Ariel Flaks]

WOW!!! TAIFUN you are the best!!! many thanks.....

Regards

[Rudolph Karstadt]

hi,

Even if it is working now,  you will not get the right number of days for every dates. eg. 09/15/2016 - 01/01/2004 = 4641   - you'll get 4640.

rudolph

[Taifun]

well, I get 4641...

http://www.calculator.net/date-calculator.html?today=01%2F01%2F2004&ageat=09%2F15%2F2016&calctype=diff&x=73&y=6

Taifun

[Hossein Amerkashi]

Alternatively, you could use DateUtils extension that uses much less blocks, auto-calculates leap years and, to my opinion, simpler to use.

Hossein  | http://AppyBuilder.com |

[Rudolph Karstadt]

Hi Taifun,

I loaded your days.aia file and I get 4640. maybe this (android) bug is only in the european (german) date format.

I found, that I get correct results by adding 12h.

here is a screenshot from a test app  which shows the wrong dates start at 01/01/2000   614 of 1000

------------------------------------------------

@Hossein

because this bug is an probably an Android thing so I get the same result with the date extension.

i think that is because the start time 0ms is 01/01/1970 1.00 am  and not 0.00

[Ariel Flaks]

Thanks a lot for the help!!. You are awesome!

[Taifun]

@Rudolf: if you calculate the duration in hours, whats the difference then? 1 hour? probably it's a daylight saving time issue then?
which Android version are you using?

Taifun

[Abraham Getzler]

Maybe it's an International Date Line problem, like 

in Around the World in 80 Days?

What's the time zone and date setting in the device or emulator?

ABG

[Rudolph Karstadt]

Hi,

yes it is 1 hour diff. 4640d 23h

using

Samsung S2 -  Android 4.12

Tablet - Android 4.03

Tablet - Android 4.42

time zone:

just testing dates between DST 0 +1h     (give me 20 min)

[Taifun]

ok

what happens, if you try to get the duration between 01/01/2004 and 11/01/2016 (i.e. a date outside of the daylight saving time)?

Taifun

[Rudolph Karstadt]

hi

you are right

it is the DST  

DST starts in Germany at march , 26   2.00am -> 3.00am  

(Test start  03/20/2017  tested with the DateUtils extension)

and then starts the 1h difference.

and ends October, 29   3.00am -> 2.00am

and i got the day back

So everything works, if you add 1h (i did 12h) to the date difference (in ms) . That is how I solved the problem.  And now I learned why ;-)

as a  matter of fact Android is right, because the number of hours (and ms) is correct and 23h are not a day and Android uses the ms to calculate the days 

greetings rudolph