Android room database won't export all the data

You need to use

JournalMode.TRUNCATE

in your AppDatabase.java:

private static AppDatabase sInstance;

public static AppDatabase getDatabase(final Context context) {
    if (sInstance == null) {
        synchronized (AppDatabase.class) {
            if (sInstance == null) {
                sInstance = Room.databaseBuilder(context, AppDatabase.class, DATABASE_NAME)
                        .setJournalMode(JournalMode.TRUNCATE)
                        .build();
            }
        }
    }
    return sInstance;
}

This method will not create db.bad and db.wal files that's creating hindrance in exporting room db.

For exporting the DB file:

Link: Exporting db with creating folder on daily basis

I had same issue. you don't need to copy wal (write ahead log file) it's a temporary file. According to documentation we need to close all connection to database before importing or exporting database. This solved my problem and now i have to copy only main database file.

Example of database class:

public abstract class AppDB extends RoomDatabase {    

    private static final Object sLock = new Object();

    private static AppDB INSTANCE;

    // create new database connection
    public static AppDB getInstance(final Context context) {
        synchronized (sLock) {
            if (INSTANCE == null) {
                INSTANCE = Room.databaseBuilder(context.getApplicationContext(), AppDB.class, "packagename")                    
                    .build();
                }
            return INSTANCE;
        }
    }

    // close database
    public static void destroyInstance(){
        if (INSTANCE.isOpen()) INSTANCE.close();
        INSTANCE = null;
    }
}

I've solved it. When exporting (saving) sql database which you handle with Room, you have to export(and later import) both - your_database.bd and your_database.wal files. Later is a journal and afaiu keeps latest records.