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NullPointerException when targeting devices running OS versions Android R or later

See original GitHub issue

Looks like there has been behavior change in OnSharedPreferenceChangeListener onSharedPreferenceChanged callback when apps target devices running OS versions Android R or later. Now when preferences are cleared null key will be received in onSharedPreferenceChanged which results in app crashing due to null value being emitted to rx stream.

Please see: https://developer.android.com/reference/android/content/SharedPreferences.OnSharedPreferenceChangeListener#onSharedPreferenceChanged(android.content.SharedPreferences, java.lang.String)

Issue Analytics

State:
Created 3 years ago
Comments:6 (4 by maintainers)

Top GitHub Comments

7reactions

davelogancommented, Sep 22, 2020

This is causing issues for my app as well after updating target version to 30.

Caused by: java.lang.NullPointerException: onNext called with null. Null values are generally not allowed in 2.x operators and sources. at io.reactivex.internal.operators.observable.ObservableCreate$CreateEmitter.onNext(ObservableCreate.java:62) at com.f2prateek.rx.preferences2.RxSharedPreferences$1$1.onSharedPreferenceChanged(RxSharedPreferences.java:44) at android.app.SharedPreferencesImpl$EditorImpl.notifyListeners(SharedPreferencesImpl.java:629) at android.app.SharedPreferencesImpl$EditorImpl.lambda$notifyListeners$0$SharedPreferencesImpl$EditorImpl(SharedPreferencesImpl.java:643)

3reactions

f2prateekcommented, Oct 1, 2020

The easy fix here would be to add a null check here. However this would result in no notification being fired when preferences are cleared, which would be less than ideal.

I think we could also make it so that it emits the default value when this happens.

emit a sentinel value in RxSharedPreferences when the key is null.
handle this sentinel value in RealPreference to emit the default value.

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