UnifiedPreferences (uniprefs)

Unified SharedPreferences for Android. Allows to use DB, JSON in addition to XML as a low level storage for SharedPreferences. Highly improved performance on low end devices. Fixed several known performance and OS resources leaks problems (which is still actual for Android 5.1.x).

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Benefits / Design Goals

• Improve performance of the SharedPreferences on low-end devices
• Fix issue with threads (Each instance of SharedPreferences creates thread which is never destroyed)
• Give ability to implement any custom de-/serialization of the data
• Memory pool, which allows to use SharedPreferences as a "short life" instance
• Statistics collecting, allows to collect some runtime counters/metrics during class usage
• Ability to store data in sqlite database
• Improved ability to store long strings in SharedPreferences

Real life

This code was used in Android project with 120 millions active users and constantly growing user database. So its heavily tested by real life. This code was developed mostly 1.5 year ago.

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Usage

For examples take look into Unit Tests. Unit Tests - SharedPreferencesTests.java

private static final String UNIT_TESTS_PREFS = "uniprefs.data.unit.tests.prefs";
private static final String UNIT_TESTS_DB = "uniprefs.data.unit.tests";

public PreferencesUnified getPreferencesUnified() {
  return new PreferencesUnified(getContext(), UNIT_TESTS_PREFS, OrgJsonSerializer.Instance);
}

public SharedPreferences getDbPreferences() {
  return PreferencesToDb.newInstance(getContext(), UNIT_TESTS_DB);
}

Migrate from old code

private static SharedPreferences newInstance(@NonNull final Context context) {
  final String preferenceName = "<IDENTIFIER>";
  final SharedPreferences to = PreferencesToDb.newInstance(context, preferenceName);

  // if migration is needed
  if (PreferencesUnified.isPreferenceExists(context, preferenceName)) {
    final SharedPreferences from = context.getSharedPreferences(preferenceName, Context.MODE_PRIVATE);
    PreferencesUnified.copy(from, to);

    // drop the default shared preferences instance
    // NOTE: in case of troubles with async logic - use commit() instead of apply()
    from.edit().clear().apply();
  }

  // return context.getSharedPreferences(preferenceName, Context.MODE_PRIVATE);
  return to;
}

Replace <IDENTIFIER> by your shared preference instance name.

License

Copyright 2015 Oleksandr Kucherenko
Copyright 2005-2015 ArtfulBits, Inc. (http://www.artfulbits.com)

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.