If you have read the documentation of the SharedPreferences you might have seen one of these warnings:
Note: This class does not support use across multiple processes.
Google even deprecated the multiprocess support because it never worked relieable
Tray is this mentioned explicit cross-process data management approach powered by a ContentProvider. Tray also provides an advanced API which makes it super easy to access and maintain your data with upgrade and migrate mechanisms. Welcome to SharedPreferences 2.0 aka Tray.
- works multiprocess
- stores simple data types as key value pairs
- automatically saves metadata for each entry (created, last updated, ...)
- manage your Preferences in modules TrayPreference
- Delete single modules, all modules, or all modules except some very important ones
- update and migrate your data from one app version to next one with versioned Preferences and a
onUpgrade()method - Migrate your current data stored in the SharedPreferences to Tray with
SharedPreferencesImport - tray is 100% unit tested!
- 0 lint warnings/errors
- Android 6.0 Auto Backup for Apps support! Read more in the wiki
Simple tutorial how to use Tray in your project instead of the SharedPreferences
// create a preference accessor. This is for global app preferences.
final AppPreferences appPreferences = new AppPreferences(getContext()); // this Preference comes for free from the library
// save a key value pair
appPreferences.put("key", "lorem ipsum");
// read the value for your key. the second parameter is a fallback (optional otherwise throws)
final String value = appPreferences.getString("key", "default");
Log.v(TAG, "value: " + value); // value: lorem ipsum
// read a key that isn't saved. returns the default (or throws without default)
final String defaultValue = appPreferences.getString("key2", "default");
Log.v(TAG, "value: " + defaultValue); // value: defaultNo Editor, no commit() or apply() 😉
It's recommended to bundle preferences in groups, so called modules instead of putting everything in one global module. If you were using SharedPreferences before, you might have used different files to group your preferences. Extending the TrayModulePreferences and put all Keys inside this class is a recommended way to keep your code clean.
// create a preference accessor for a module
public class MyModulePreference extends TrayPreferences {
public static String KEY_IS_FIRST_LAUNCH = "first_launch";
public MyModulePreference(final Context context) {
super(context, "myModule", 1);
}
}// accessing the preferences for my own module
final MyModulePreference myModulePreference = new MyModulePreference(getContext());
myModulePreference.put(MyModulePreference.KEY_IS_FIRST_LAUNCH, false);See the sample project for more
Like the Android SQLiteOpenHelper a TrayPreference lets you implement methods to handle versioning.
public class MyModulePreference extends TrayPreferences {
public MyModulePreference(final Context context) {
super(context, "myModule", 1);
}
@Override
protected void onCreate(final int initialVersion) {
super.onCreate(initialVersion);
}
@Override
protected void onUpgrade(final int oldVersion, final int newVersion) {
super.onUpgrade(oldVersion, newVersion);
}
@Override
protected void onDowngrade(final int oldVersion, final int newVersion) {
super.onDowngrade(oldVersion, newVersion);
}
}// TOOD add clear sample
To migrate values from SharedPreferences you have to create you own preference module. This module will be now store all of your SharedPreferences values.
public class ImportPreferences extends TrayPreferences {
// The SharedPreferences name
private static final String SHARED_PREFERENCES_FILE_NAME = "PREF_NAME";
// The key inside the SHARED_PREFERENCES_NAME
private static final String KEY_FIRST_LAUNCH = "KEY_FIRST_LAUNCH";
// The new key for this module
private static final String KEY_FIRST_LAUNCH_TRAY = "KEY_FIRST_LAUNCH_TRAY";
public ImportPreferences(@NonNull Context context) {
super(context, "myImportModule", 1);
}
// Called only once when the module was created
@Override
protected void onCreate(int initialVersion) {
super.onCreate(initialVersion);
// Create a SharedPreferencesImport object
SharedPreferencesImport importPref =
new SharedPreferencesImport(getContext(),
SHARED_PREFERENCES_FILE_NAME, KEY_FIRST_LAUNCH, KEY_FIRST_LAUNCH_TRAY);
// Finally migrate it
migrate(importPref);
}
}repositories {
maven {
url = uri("https://maven.pkg.github.com/GCX-HCI/tray")
}
}
dependencies {
implementation "net.grandcentrix.tray:tray:0.12.0"
}
repositories {
jcenter()
}
dependencies {
implementation "net.grandcentrix.tray:tray:0.12.0"
}
More on the ContentProvider configuration can be found in the wiki
Tray has 100% test coverage and we'll try to keep it at that level for stable releases.
You can run the coverage report with ./gradlew createDebugCoverageReport. You'll find the output in library/build/outputs/coverage/debug/index.html which looks like this:
You can check the coverage report at codecov.io
Those ~170 tests will help us indicate bugs in the future before we publish them. Don't think the code is 100% bug free based on the test coverage.
At first, it was the simplest way to use IPC with Binder to solve the multiprocess problem. Using the ContentProvider with a database turned out to be very handy when it comes to save metadata. We thought about replacing the database with the real SharedPreferences to boost the performance (the SharedPreferences do not access the disk for every read/write action which causes the multiprocess problem btw) but the metadata seemed to be more valuable to us. see more informations
If you have found a better solution implement the TrayStorage and contribute to this project! We would appreciate it.
That said, yes the performance isn't as good as the SharedPreferences. But the performance is good enough to save/access single key value pairs synchron. If you want to save more you should think about a simple database.
Tray is ready to use without showblockers! But here are some nice to have features for the future:
- Reactive wrapper to observe values
- no support to save
Set<String>. Is someone using this? - more metadata fields: (i.e. app version code/name)
- performance tests
- memory cache for based on contentobservers
- prevent app crashes due to database errors
- rx wrapper for changes
- save additional data types (
Set<String>,byte[])
- preference key cannot be empty #84
clearBut(TrayPreference)->clearBut(AbstractTrayPreference)#89
- all accessor methods return
booleanindicating the success of i.e.put,remove. They will never again throw an error. #69 - new
contains()method #74
- All features and changes of the 1.0.0-rc preview builds
- #65 Fix deletion of non string migrated shared preferences.
- hotfix for listener on Android 6.0 which has caused a infinity loop #55
- the sample project includes now a way to test the multi process support compared to the
SharedPreferences - removed unnecessary write operation for every version check #54
- added logging for all data changing methods. Enable via
adb shell setprop log.tag.Tray VERBOSE
- Android M Auto Backup feature support (see the Documentation)
- split up database for user and device specific data (device specific data can now be excluded from the auto backup)
TrayPreferenceshas now an optional 3. constructor parameterTrayStorage.Type,USERorDEVICEindicating the internal database (required for Android M Auto Backup). Default isUSER
- New methods and changes
PreferenceAccessor#wipe()clears the preference data and it's internal data (version)TrayPreferences#annexModule(String name)imports a module by name and wipes it afterwards. This allows renaming of preferences without losing dataAbstractTrayPreference#annex(ModularizedStorage<TrayItem>)allows a storage to import another storage, wipes the imported afterwardsPreference#onCreate(...)and#onUpgrade(...)aren't abstract anymore because they don't require an implementation
- Deprecations (will be removed soon)
TrayAppPreferencesis now deprecated. UseAppPreferencesinstead (renaming)TrayModulePreferencesis now deprecated. UseTrayPreferencesinstead to extend from for your own Preferences
- Internal structure
- new package structure. merged packages
accessor,migrationandstorageintocore - package
providercontains aTrayStorageimplementation with aContentProvider. Is easy exchangeable with anotherTrayStorageimplementation ModularizedTrayPreferenceis now calledAbstractTrayPreferenceModularizedStoragewas renamed toTrayStorage
- new package structure. merged packages
getContext()is working inTrayModulePreference#onCreate
- saving
nullwithmPref.put(KEY, null)works now - access to preference with throwing methods instead of default value (throws ItemNotFoundException). Example:
mPref.getString(KEY);instead ofmPref.getString(KEY, "defaultValue"); - WrongTypeException when accessing a preference with a different type and the data isn't parsable. Float (
10.1f) -> String works, String ("10.1") -> Float works, String ("test") -> Float throws! - javadoc in now included in aar
- initial public release
- Refactoring
- 100% Testing
- Bugfixing
- first working prototype
- Pascal Welsch - https://github.com/passsy
- Jannis Veerkamp - https://github.com/jannisveerkamp
Copyright 2015 grandcentrix GmbH
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.
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