CODEWITHSUNDEEP
androidsqliteandroid-sqliteandroid-roomandroid-architecture-components
Слава Курай
Слава Курай

Reputation: 11

How can i populate Room Persistence database in Android?

I have an old database with the next structure: Database structure

The question is what is the best way to create and populate tables in Room Persistence Database. The way i do it now is a storing tables data in strings.xml and push it into database with firstrun.

 public void createDb(final Context context) {
    mIsDatabaseCreated.setValue(false);

    prefs = context.getSharedPreferences(context.getPackageName(), Context.MODE_PRIVATE);

    boolean isFirstRun = prefs.getBoolean(prefKey, true);
    Observable.just(Room.databaseBuilder(context.getApplicationContext(),
            AppDatabase.class, AppDatabase.DATABASE_NAME).build())
            .map(appDatabase1 -> DatabaseInitUtil.initializeDb(
                    appDatabase1, 
                    context.getResources().getStringArray(R.array.themes),
                    isFirstRun))
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(appDatabase -> {
                mDb = appDatabase;
                mIsDatabaseCreated.setValue(true);
            });

    prefs.edit().putBoolean(prefKey, false).apply();
}

 static AppDatabase initializeDb(AppDatabase appDatabase, String[] themes, boolean isFirstRun) {

    if (isFirstRun) {
        List<ThemeEntity> themesEntities = new ArrayList<>(themes.length);
        generateData(themesEntities, themes);
        return insertData(appDatabase, themesEntities);
    } else {
        return appDatabase;
    }

}

private static void generateData(List<ThemeEntity> themesEntities, String[] themes) {
    for (String theme : themes) {
        ThemeEntity themeEntity = new ThemeEntity();
        themeEntity.setTheme(theme);
        themesEntities.add(themeEntity);
    }
}


<string-array name="themes">
    <item>@string/courage</item>
    <item>@string/death</item>
    <item>@string/forgiveness</item>
    <item>@string/faith</item>
    <item>@string/family</item>
    <item>@string/encouragement</item>
    <item>@string/friendship</item>
    <item>@string/joy</item>
    <item>@string/life</item>
    <item>@string/love</item>
    <item>@string/relationship</item>
    <item>@string/strength</item>
</string-array>

But i think that storing a large data in strings arrays and get it with first run it is not right way.

Upvotes: 1

Views: 1068

Answers (2)

xcesco
xcesco

Reputation: 4838

I known the answer is associated to Room library, but the real problem is that you want to populate a SQLite database when it is created.

What i can do is show how to accomplish this task using another open source library called Kripton Persistence Library.

First of all, as suggested by other answer, it's better to use a JSON file store in the raw folder of your project. Then with Kripton the task is quite simple. In method onCreate of you application class, supposed you database is called QuickStartDataSource, just write code similar to this (it's an incomplete code but i think it understandable):

BindQuickStartDataSource ds = BindQuickStartDataSource.build(DataSourceOptions.builder().databaseLifecycleHandler(new DatabaseLifecycleHandler() {

  @Override
  public void onCreate(SQLiteDatabase database) {
   // read json data from a file
   KriptonJsonContext jsonBinder = KriptonBinder.jsonBind();
   YouObject bean=jsonBinder.parse(.., YouObject.class);

   // insert data
   database.execSQL(..);  
  }

}).build();

Kripton manage persistence on SQLite, SharedPreference and file system too. I suggest you to read its documentation.

For more information about Kripton Persistence Library:

Upvotes: 0

Ashutosh Sagar
Ashutosh Sagar

Reputation: 1009

Try making a JOSN of data and store it in assets and when ever you need just push it in the DB and JOSN is much easier to read.

Upvotes: 1

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