ExternalRoomReadDbFromFile

part 5, setelah zip dibuat , buat instanse untuk room

Using Room as your local database.

Code for AppDataBase

@Database(entities = {SampleTable.class}, version = 3)
public abstract class AppDatabase extends RoomDatabase {

    private static final String TAG = "AppDatabase";
    public static String dbName = "ExternalBase64Md5ToZip.db";

    public abstract SampleTableDao sampleTableDao();

    public static AppDatabase getInstance(Context context) {
        File folder = new File(Environment.getExternalStorageDirectory().toString()+"FolderOnExternal"+"/db"+dbName);
        return Room.databaseBuilder(context,
                AppDatabase.class, dbName)
                .createFromFile(folder)
                .allowMainThreadQueries()
                .build();
    }

    public void copyFile(AppDatabase appDatabase) {
        appDatabase.close();
        try {
            File localDir = new File(Environment.getExternalStorageDirectory().toString()+"FolderOnExternal"+"/db");
            File sd = Environment.getExternalStorageDirectory();

            if (sd.canWrite()) {
                String currentDBPath = appDatabase.getOpenHelper().getWritableDatabase().getPath();
                String backupDBPath = AppDatabase.dbName;
                File currentDB = new File(currentDBPath);
                File backupDB = new File(localDir, backupDBPath);
                Log.d(TAG, "path local  "+localDir.toString());
                Log.d(TAG, "path sumber  "+currentDB.toString());
                Log.d(TAG, "path tujuan  "+backupDB.toString());

                if (currentDB.exists()) {
                    FileChannel src = new FileInputStream(currentDB).getChannel();
                    FileChannel dst = new FileOutputStream(backupDB).getChannel();
                    dst.transferFrom(src, 0, src.size());
                    src.close();
                    dst.close();
                }
            } else {
                Log.d(TAG, "path Cannon write");
            }
        } catch (Exception e) {
            e.printStackTrace();
            Log.d(TAG, "path "+e.getMessage());
        }
    }
}

Important

Every new transaction process Insert, Update, Delete or ON APP DESTROY you should use copyFile to close Database and backup Database Room from root to eksternal. Here is the example.

AppDatabase appDatabase = AppDatabase.getInstance(getApplicationContext());

appDatabase.sampleTableDao().insertAll(new SampleTable(0, "data baru"));
appDatabase.copyFile(appDatabase);

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Copyright 2020 M. Fadli Zein