How to migrate SharedPrefs to DefaultSharedPrefs?

Question

I have an issue, i'm refactoring my App written years a go, i've changed the whole Settings activity which first was a simple activity with custom checkboxes and edittexts which was saving data in a custom SharedPrefs "settings".

Today i've rewritted the whole Settings by using root_preferences, so the old and the new datas are saved in different SharedPrefs, old data are in SharedPrefs "settings" and the new one in DefaultSharedPreferences, another point is that in the old Settings page all the switches values was saved as a string like if the switch was on i was saving "ON" else "OFF" and i would refactor even this by simply settings SwitchPreferenceCompat saved value to "ON" / "OFF" to make it simplier.

Which would be the way i should take to "migrate" the SharedPrefs from settings to DefaultSharedPrefs?

As if i'd update the App now to someone it will still read values from SharedPrefs settings and the data set in new Settings page will be useless...

EDIT: After following the @snachmsm raccomandations i've ended up by doing a version check of the application (to check if it's the first run or if it's an old version with old settings activity) by reusing the code from this answer and them i've just made a function which make the whole preferences migration from old values and old shared prefs to new one.

Here is how my code looks like:

@Override
protected void onCreate(Bundle savedInstanceState) {

    SharedPreferences sharedPreferences =
            PreferenceManager.getDefaultSharedPreferences(this);
    checkFirstRun(sharedPreferences);

}

private void checkFirstRun(SharedPreferences sharedPreferences) {
    final String PREFS_NAME = "FirstRun";
    final String PREF_VERSION_CODE_KEY = "version_code";
    final int DOESNT_EXIST = -1;

    int currentVersionCode = BuildConfig.VERSION_CODE;
    SharedPreferences prefs = getSharedPreferences(PREFS_NAME, MODE_PRIVATE);
    int savedVersionCode = prefs.getInt(PREF_VERSION_CODE_KEY, DOESNT_EXIST);

    // Check for first run or upgrade
    if (currentVersionCode == savedVersionCode) {
        return;
    } else if (savedVersionCode == DOESNT_EXIST) {
        migratePreferences(sharedPreferences);
    } else if (currentVersionCode > savedVersionCode) {
        // UPGRADE
    }

    // Update the shared preferences with the current version code
    prefs.edit().putInt(PREF_VERSION_CODE_KEY, currentVersionCode).apply();
}

private void migratePreferences(SharedPreferences sharedPreferences) {
    SharedPreferences oldPrefs = getSharedPreferences("settings",MODE_PRIVATE);
    if (oldPrefs.getAll().size() == 0) {
        return;
    }
    SharedPreferences.Editor preferencesEditor = sharedPreferences.edit();
    preferencesEditor.putString("ip", oldPrefs.getString("ip", "10.0.0.51"));
    preferencesEditor.putString("txtArt", oldPrefs.getString("txtArt", "10.0.0.51"));
    preferencesEditor.putString("txtTasti", oldPrefs.getString("txtTasti", "10.0.0.51"));
    preferencesEditor.putString("txtTerm", oldPrefs.getString("txtTerm", "1"));
    preferencesEditor.putString("txtColonne", oldPrefs.getString("txtColonne", "4"));
    preferencesEditor.putString("varianti", String.valueOf(oldPrefs.getInt("varianti", 5)));
    preferencesEditor.putString("turni", String.valueOf(oldPrefs.getInt("turni", 0)));
    preferencesEditor.putBoolean("sottoTavoli", oldPrefs.getString("sottoTavoli", "OFF").equals("ON"));
    preferencesEditor.putBoolean("prezzoTasto", oldPrefs.getString("prezzoTasto", "OFF").equals("ON"));
    preferencesEditor.putBoolean("chiediConto", oldPrefs.getString("chiediConto", "OFF").equals("ON"));
    preferencesEditor.putBoolean("prossimoTurno", oldPrefs.getString("prossimoTurno", "OFF").equals("ON"));
    preferencesEditor.putBoolean("prezz", oldPrefs.getString("prezz", "OFF").equals("ON"));
    preferencesEditor.putBoolean("switchMsg", oldPrefs.getString("switchMsg", "OFF").equals("ON"));
    preferencesEditor.putBoolean("soloSotto", oldPrefs.getString("soloSotto", "OFF").equals("ON"));
    preferencesEditor.putBoolean("night", oldPrefs.getString("night", "OFF").equals("ON"));
    preferencesEditor.putBoolean("tastiLaterali", oldPrefs.getString("tastiLaterali", "OFF").equals("ON"));
    preferencesEditor.putBoolean("famSwitch", oldPrefs.getString("famSwitch", "OFF").equals("ON"));
    preferencesEditor.putBoolean("riproponiTurno", oldPrefs.getString("riproponiTurno", "OFF").equals("ON"));
    preferencesEditor.putBoolean("ricaricatasti", oldPrefs.getString("famSwitch", "OFF").equals("ON"));
    preferencesEditor.putBoolean("order", oldPrefs.getBoolean("order", false));
    preferencesEditor.putBoolean("fidelity", oldPrefs.getBoolean("order", false));
    preferencesEditor.apply();


    // Deleting all old prefs.
    oldPrefs.edit().clear().apply();

}

score 1 · Accepted Answer · answered Jul 23 '21 at 08:52

1

I'm afraid that there is no simple solution for your case. At least you may introduce some migration method at very beginning of your app start (extended Application class?)

At first fetch old ShardedPreferences ("settings"), then iterate through and write values to DefaultSharedPreferences, after each remove key or at the end remove whole old file (API24+). in this method you can introduce "ON"/"OFF" -> boolean migration for cleaner code (as you made a refactoring)

answered Jul 23 '21 at 08:52

snachmsm

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i've just made it, the only thing i've skipped it was the iteration as in some cases the values are not all strings, check my question edit, thank you. :) – NiceToMytyuk Jul 23 '21 at 09:16

How to migrate SharedPrefs to DefaultSharedPrefs?

1 Answers1