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[Flutter/dart] Check if late variable is initialized


What want to do

  • There is a variable that remain unchanged once the initial value is determined.

  • However, it cannot be determined yet when the constructor is called.


About such variable

  • Define the variable with late final

  • Check whether it has been initialized (at some timing), and if it has not, set the initial value (if you do not check, you will get an error of assigning a value to final)


In this case, I didn't know how to check whether it was initialized.

I thought I could just check if it was null, but even if I checked for null, if I referenced an uninitialized variable, a reference error occurred.



Solution

The official opinion seems to be that such checks should not be done.


In this case, you can make it a nullable variable, set the initial value to null, and set the initial value if it is null.

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