IssueTracker

re-opening https://issuetracker.google.com/141678219

hitting this same issue.

My code:

public void onCreatePreferences(@Nullable final Bundle savedInstanceState,
                                @Nullable final String rootKey) {
    super.onCreatePreferences(savedInstanceState, rootKey);
    setPreferencesFromResource(R.xml.preferences_style, rootKey);

    pTextScale = findPreference(TextScale.PK_TEXT_SCALE);
    pTextScale.setPreferenceDataStore(styleDataStore);

Here is a debug trace:

java.lang.Thread.State: RUNNABLE
  at androidx.preference.Preference.getPersistedInt(Preference.java:1809)
  at androidx.preference.SeekBarPreference.onSetInitialValue(SeekBarPreference.java:207)
  at androidx.preference.Preference.onSetInitialValue(Preference.java:1634)
  at androidx.preference.Preference.dispatchSetInitialValue(Preference.java:1607)
  at androidx.preference.Preference.onAttachedToHierarchy(Preference.java:1330)
  at androidx.preference.Preference.onAttachedToHierarchy(Preference.java:1345)
  at androidx.preference.PreferenceGroup.addPreference(PreferenceGroup.java:253)
  at androidx.preference.PreferenceGroup.addItemFromInflater(PreferenceGroup.java:173)
  at androidx.preference.PreferenceInflater.rInflate(PreferenceInflater.java:350)
  at androidx.preference.PreferenceInflater.rInflate(PreferenceInflater.java:351)
  at androidx.preference.PreferenceInflater.inflate(PreferenceInflater.java:161)
  - locked <0x5848> (a java.lang.Object[])
  at androidx.preference.PreferenceInflater.inflate(PreferenceInflater.java:112)
  at androidx.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:217)
  at androidx.preference.PreferenceFragmentCompat.setPreferencesFromResource(PreferenceFragmentCompat.java:380)
  at com.hardbacknutter.nevertoomanybooks.settings.styles.StyleFragment.onCreatePreferences(StyleFragment.java:101)
  at androidx.preference.PreferenceFragmentCompat.onCreate(PreferenceFragmentCompat.java:161)

The library code:

protected int getPersistedInt(int defaultReturnValue) {
    if (!shouldPersist()) {
        return defaultReturnValue;
    }

    PreferenceDataStore dataStore = getPreferenceDataStore();   <== still NULL of course
    if (dataStore != null) {
        return dataStore.getInt(mKey, defaultReturnValue);
    }

    return mPreferenceManager.getSharedPreferences().getInt(mKey, defaultReturnValue);

It's easy to see that the call to setPreferencesFromResource() ends up using the value from SharedPreferences and not from my datastore. But I can't set a PreferenceDataStore until that call is done.

Conclusion: when using setPreferencesFromResource, you simply cannot use PreferenceDataStore. I presume no one tested this?

I don't fancy building my preference screen totally from code just to be able to set the PreferenceDataStore. In that case I might as well just dump the whole preference library.

any thoughts?

and please do not say "migrate to the new datastore/kotlin/flow" - I'd have to dump the preference library as well to do that + add the mess called 'kotlin' ; no thanks.