i get this error while using shared preference in android. 'java.lang.NullPointerException: Attempt ...

# multiplatform

[Praveen Kumar]

i get this error while using shared preference in android.
'java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.SharedPreferences android.content.Context.getSharedPreferences(java.lang.String, int)' on a null object reference'

[Jeff Lockhart]

Seems you have a null Context reference. How is this related to multiplatform? Seems you're using a Java API that allows a platform type instead of nullable API. Most of Android's APIs have been annotated @Nullable or @NonNull for a while for better interop with Kotlin's nullable types. Where are you getting your Context reference from?

[Praveen Kumar]

actual typealias KMMContext = Application

here

[Praveen Kumar]

https://medium.com/@shmehdi01/shared-preference-in-kmm-kotlin-multiplatform-2bca14214093
i follow this article

[Jeff Lockhart]

Where are you getting your applicationContext reference you're passing here?

val pref = KMMPreference(applicationContext)

[Praveen Kumar]

actual typealias KMMContext = Application

here, this is from

[Jeff Lockhart]

That's just defining a platform typealias. You actually need a Application context reference on Android to use as indicated:

val pref = KMMPreference(applicationContext)

What are you passing here for applicationContext?

[Praveen Kumar]

That’s from androidMain. above i have sent.

[Jeff Lockhart]

I'm sorry I can't help you further if you can't understand and answer my question. Somewhere you are creating a KMMPreference object, passing it a KMMContext reference. On Android, KMMContext is typealiased to Application (specifically android.app.Application, which is an Android Context). When you construct KMMPreference, you are required to pass it a non-null Application Context reference. Where are you getting this reference from?

Again, this is in your code:

val pref = KMMPreference(applicationContext)

Where is applicationContext coming from? The error you shared indicates that this reference is null, causing the crash.