How to convert Calendar to Date in Kotlin?

Question

I am trying to add one month to a date with Calendar.getInstance() but I can't figure out why there is error "java.lang.ClassCastException : java.util.Date cannot be cast to java.lang.Number" when trying to get the Calendar to a Date object.

Here's the source code that I am using :

    val date = Date()
    val cal = Calendar.getInstance()
    cal.time = date
    cal.add(Calendar.MONTH, 1)
    val datePlusOneMonth: Date = cal.time

The code you provided works fine on my side. Maybe error appears somewhere else in your code? Please check logs and look for the line number of the error — Sergio, Mar 27 '19 at 13:47
cal.time = date has not need here, otherwise what line gives you this error ? — Amine, Mar 27 '19 at 13:47
Sergey, are you sure that it runs ok ? Because the exception does not trigger any bug in the application. It is only when I put a breakpoint and then go to Evaluate Expression window that I see the error when calling cal.time — KotlinIsland, Mar 27 '19 at 14:01
Amine, you say right, cal.time = Date is not needed. Thanks. (Error still happening anyway) — KotlinIsland, Mar 27 '19 at 14:02
Yes I have. You can set log after line `val datePlusOneMonth: Date = cal.time` and check it — Sergio, Mar 27 '19 at 14:10
One thing I find bizarre is that when adding a try/catch block, then the code does not go in the catch block... — KotlinIsland, Mar 27 '19 at 14:10

KotlinIsland · Accepted Answer · 2019-03-28T09:15:51.497

Thank you Sergey... The code runs ok. But I have been disappointed because I added a useless line of code in order to debug and I had put a breakpoint on it :

val datePlusOneMonth: Date = cal.time
val ok = false

And I had put the breakpoint on the "val ok = false" and the debugger never stopped on "val ok = false" because "ok" was never used.

Then to have the debugger stop on "val ok = false" I had to do the following :

val datePlusOneMonth: Date = cal.time
val ok = false
val ok2 = ok

And then I could add the breakpoing on "val ok = false" and yes the code runs well.

score 2 · Answer 2 · answered Mar 28 '19 at 05:43

2

try this code

val datePlusOneMonth = Calendar.getInstance().run {
    add(Calendar.MONTH, 1)
    time
}

answered Mar 28 '19 at 05:43

ib_ganz

111
1
8

Ok thanks for the answer, but we figured out that my code runs correctly. Anyway I'll consider this next time. – KotlinIsland Mar 28 '19 at 08:32

How to convert Calendar to Date in Kotlin?

2 Answers2