am 4fc279c9: Remove the prior state preference when deleting a TimerObj

    };

    public void writeToSharedPref(SharedPreferences prefs) {

        final SharedPreferences.Editor editor = prefs.edit();

        final String id = Integer.toString(mTimerId);

        editor.putInt(PREF_TIMER_ID + id, mTimerId);

        editor.putLong(PREF_START_TIME + id, mStartTime);

        editor.putLong(PREF_TIME_LEFT + id, mTimeLeft);

        editor.putLong(PREF_ORIGINAL_TIME + id, mOriginalLength);

        editor.putLong(PREF_SETUP_TIME + id, mSetupLength);

        editor.putInt(PREF_STATE + id, mState);

        editor.putInt(PREF_PRIOR_STATE + id, mPriorState);

        final Set<String> timersList = prefs.getStringSet(PREF_TIMERS_LIST, new HashSet<String>());

        timersList.add(id);

        editor.putStringSet(PREF_TIMERS_LIST, timersList);

        editor.putString(PREF_LABEL + id, mLabel);

        editor.putBoolean(PREF_DELETE_AFTER_USE + id, mDeleteAfterUse);

        final SharedPreferences.Editor editor = prefs.edit()

                .putInt(PREF_TIMER_ID + id, mTimerId)

                .putLong(PREF_START_TIME + id, mStartTime)

                .putLong(PREF_TIME_LEFT + id, mTimeLeft)

                .putLong(PREF_ORIGINAL_TIME + id, mOriginalLength)

                .putLong(PREF_SETUP_TIME + id, mSetupLength)

                .putInt(PREF_STATE + id, mState)

                .putInt(PREF_PRIOR_STATE + id, mPriorState)

                .putStringSet(PREF_TIMERS_LIST, timersList)

                .putString(PREF_LABEL + id, mLabel)

                .putBoolean(PREF_DELETE_AFTER_USE + id, mDeleteAfterUse);

        editor.apply();

    }

    public void readFromSharedPref(SharedPreferences prefs) {

        String id = Integer.toString(mTimerId);

        String key = PREF_START_TIME + id;

        mStartTime = prefs.getLong(key, 0);

        key = PREF_TIME_LEFT + id;

        mTimeLeft = prefs.getLong(key, 0);

        key = PREF_ORIGINAL_TIME + id;

        mOriginalLength = prefs.getLong(key, 0);

        key = PREF_SETUP_TIME + id;

        mSetupLength = prefs.getLong(key, 0);

        key = PREF_STATE + id;

        mState = prefs.getInt(key, 0);

        key = PREF_PRIOR_STATE + id;

        mPriorState = prefs.getInt(key, 0);

        key = PREF_LABEL + id;

        mLabel = prefs.getString(key, "");

        key = PREF_DELETE_AFTER_USE + id;

        mDeleteAfterUse = prefs.getBoolean(key, false);

    }

    public void deleteFromSharedPref(SharedPreferences prefs) {

        SharedPreferences.Editor editor = prefs.edit();

        String key = PREF_TIMER_ID + Integer.toString(mTimerId);

        String id = Integer.toString(mTimerId);

        editor.remove (key);

        key = PREF_START_TIME + id;

        editor.remove (key);

        key = PREF_TIME_LEFT + id;

        editor.remove (key);

        key = PREF_ORIGINAL_TIME + id;

        editor.remove (key);

        key = PREF_SETUP_TIME + id;

        editor.remove (key);

        key = PREF_STATE + id;

        editor.remove (key);

        Set <String> timersList = prefs.getStringSet(PREF_TIMERS_LIST, new HashSet<String>());

        final String id = Integer.toString(mTimerId);

        mStartTime = prefs.getLong(PREF_START_TIME + id, 0);

        mTimeLeft = prefs.getLong(PREF_TIME_LEFT + id, 0);

        mOriginalLength = prefs.getLong(PREF_ORIGINAL_TIME + id, 0);

        mSetupLength = prefs.getLong(PREF_SETUP_TIME + id, 0);

        mState = prefs.getInt(PREF_STATE + id, 0);

        mPriorState = prefs.getInt(PREF_PRIOR_STATE + id, 0);

        mLabel = prefs.getString(PREF_LABEL + id, "");

        mDeleteAfterUse = prefs.getBoolean(PREF_DELETE_AFTER_USE + id, false);

    }

    public boolean deleteFromSharedPref(SharedPreferences prefs) {

        final String id = Integer.toString(mTimerId);

        final Set<String> timersList = prefs.getStringSet(PREF_TIMERS_LIST, new HashSet<String>());

        timersList.remove(id);

        editor.putStringSet(PREF_TIMERS_LIST, timersList);

        key = PREF_LABEL + id;

        editor.remove(key);

        key = PREF_DELETE_AFTER_USE + id;

        editor.remove(key);

        final SharedPreferences.Editor editor = prefs.edit()

                .remove(PREF_TIMER_ID + id)

                .remove(PREF_START_TIME + id)

                .remove(PREF_TIME_LEFT + id)

                .remove(PREF_ORIGINAL_TIME + id)

                .remove(PREF_SETUP_TIME + id)

                .remove(PREF_STATE + id)

                .remove(PREF_PRIOR_STATE + id)

                .putStringSet(PREF_TIMERS_LIST, timersList)

                .remove(PREF_LABEL + id)

                .remove(PREF_DELETE_AFTER_USE + id);

        if (timersList.isEmpty()) {

            editor.remove(KEY_NEXT_TIMER_ID);

        }

        editor.commit();

        return editor.commit();

    }

    @Override