Why we can't declare variable as "var" for lazy initialization

Asked Jan 18 '21 at 08:14

Active Jan 18 '21 at 08:23

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private var TodosAdapter by lazy{ TodosAdapter() }

This is my code and when i declare it like this, compiler throws an error that var should be changed to val

I am wondering when we declare it as val doesn't it change the value of TodosAdapter afterwards? I mean normally we can't change the value of variable declared as val. How this happens, can somebody explain what is working behind this

edited Jan 18 '21 at 08:17

a_local_nobody

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asked Jan 18 '21 at 08:14

nasibeyyubov

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https://kotlinlang.org/docs/reference/delegated-properties.html – nhaarman Jan 18 '21 at 08:18
Perhaps it would be helpful for you to include the compile error in your question. – khelwood Jan 18 '21 at 08:29
@khelwood compiler error is already included "var should be changed to val". – Dalija Prasnikar Jan 18 '21 at 08:37
@DalijaPrasnikar I expect the error message is probably a bit more detailed than that. – khelwood Jan 18 '21 at 08:38
@khelwood No, it is not and message itself is quite obvious. What is not obvious, and compiler message cannot relay in single sentence, is why and that is the question. – Dalija Prasnikar Jan 18 '21 at 09:11
Type 'Lazy' has no method 'setValue(TodosFragment, KProperty<*>, TodosAdapter)' and thus it cannot serve as a delegate for var (read-write property – nasibeyyubov Jan 18 '21 at 12:52
Above is the full error, i read the documentation of delegated-properties as did not find answer to my question. I want to know why we can't declare it as "var" – nasibeyyubov Jan 18 '21 at 12:53

Why we can't declare variable as "var" for lazy initialization

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