KVS Schema

KVS Schema is a library to manage key-value data for Android. This library generates methods from annotated fields in compile time. For example, when a schema class has @Key("user_id") String userId like below,

@Table(name = "example")
public class ExamplePrefsSchema {
    @Key("user_id") String userId;
}

KVS Schema generates accessor methods below.

• ExamplePrefs#getUserId
• ExamplePrefs#putUserId
• ExamplePrefs#removeUserId
• ExamplePrefs#hasUserId

Values are stored on SharedPreferences through generated class.

How to use

Create Schema

Class name should be *Schema.

@Table(name = "example")
public class ExamplePrefsSchema {
    @Key("user_id") int userId;
    @Key("user_name") String userName;
}

Read and Write

put*, get*, has* and remove* methods will be generated in compile time.

ExamplePrefs prefs = ExamplePrefs.get(context);
prefs.putUserId(123);
prefs.putUserName("Jack");
prefs.hasUserName(); // => true
prefs.getUserName(); // => Jack
prefs.removeUserName();
prefs.hasUserName(); // => false

Initialize method (ExamplePrefs.get) is also generated. It provides singleton instance of Prefs. You can change initialize method of Prefs by specifying builder class.

@Table(name = "example", builder = ExamplePrefsBuilder.class)

See: rejasupotaro#12

Supported types

kvs-schema supports these types for now.

• boolean
• String
• float
• int
• long
• String set

Saved XML

Table's name becomes SharedPreferences' name.

root@android:/data/data/com.example.android.kvs/shared_prefs # cat example.xml
<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<map>
<string name="user_id">123</string>
</map>

Installation

This library is distributed by JitPack. Add dependencies your build.gradle

apt 'com.github.rejasupotaro.kvs-schema:compiler:3.0.0'
compile 'com.github.rejasupotaro.kvs-schema:library:3.0.0'

Migration

Even if you have already used SharedPreferences directly, migration is easy. KVS Schema simply maps the structure of SharedPreferences.

For example, if you are using default SharedPreferences like below,

prefs = PreferenceManager.getDefaultSharedPreferences(this);
Editor editor = prefs.edit();
editor.putString("user_id", "1");
editor.putString("user_name", "rejasupotaro");
editor.apply();

your data is saved on path/to/app/shared_prefs/package_name_preferences.xml. The schema becomes below.

@Table("package_name_preferences")
public abstract class ExamplePrefsSchema {
    @Key("user_id") int userId;
    @Key("user_name") String userName;
}

See concrete example: konifar/droidkaigi2016#311

In addition, SharedPreferencesInfo may help you to migrate existing app. You can get existing SharedPreferences through SharedPreferencesInfo.getAllPrefsAsTable.

List<SharedPreferencesTable> tables = SharedPreferencesInfo.getAll(this);
        for (SharedPreferencesTable table : tables) {
            Log.d("DEBUG", table.toString());
        }

You can see what kind of data is saved in your app like below.

   name: com.example.android.kvs_preferences
   path: /data/data/com.example.android.kvs/shared_prefs/com.example.android.kvs_preferences.xml
 ╔═══════════╤══════════════╤════════╗
 ║ Key       │ Value        │ Type   ║
 ╠═══════════╪══════════════╪════════╣
 ║ user_name │ rejasupotaro │ String ║
 ╟───────────┼──────────────┼────────╢
 ║ user_id   │ 1            │ String ║
 ╚═══════════╧══════════════╧════════╝

Development

Show version

$ ./gradlew version

Bump version

$ ./gradlew bumpMajor
$ ./gradlew bumpMinor
$ ./gradlew bumpPatch

Generate README

$ ./gradlew genReadMe