android Skipped 44 frames! The application may be doing too much work on its main thread

I am developing a book app using Java and SQLite and I want to show the list of the contents in a list view. I have already solved a few errors for opening the database but now the database opens but nothing is showing in the list view and I receive that error.

The code for my activity. This activity starts after clicking on a button in the main activity:

import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import androidx.appcompat.app.AppCompatActivity;

import java.util.List;

public class LVSwitches extends AppCompatActivity {
public static final String LOGTAG="book";
private BookDataSource dataSource;
private List<season> seasons;
private ListView listView;
private ArrayAdapter<season> adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_l_v_switches);
    listView = (ListView) findViewById(R.id.season_list);
    dataSource=new BookDataSource(getBaseContext());
    this.seasons = this.dataSource.getAllSeasons();
    //dataSource.getAllSeasons();
    if (seasons.size()==0){
        this.dataSource.CopyDbfile();

        this.seasons = this.dataSource.getAllSeasons();
    }

}

}

Here is the code for the data source

public class BookDataSource {
private Context context;
private SQLiteDatabase database;
private SQLiteOpenHelper dbhelper;
private static String DB_PATH = "";
private static String DB_NAME = "lvs";

public BookDataSource(Context context){
    this.context=context;
    this.dbhelper=new bookDBHelper(context);
    DB_PATH = "/data/data/" + context.getPackageName() + "/databases/";
}
public void openDb(){
    database=dbhelper.getWritableDatabase();
    String myPath = DB_PATH + DB_NAME;
    database = SQLiteDatabase.openDatabase
            (myPath, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS | SQLiteDatabase.OPEN_READWRITE);
    Log.i(LVSwitches.LOGTAG,"database opened");
}
public void closeDb(){
    if (database!=null){
        database.close();
        //Log.i(LVSwitches.LOGTAG,"database closed");
    }else {
       Log.i(LVSwitches.LOGTAG,"db=null");
    }
}
public List<season> getAllSeasons(){
    List<season> items=new ArrayList<season>();
    openDb();
    String[] colums= {bookDBHelper.KEY_ID,bookDBHelper.KEY_CONTENT,bookDBHelper.KEY_ISFAV};
    Cursor cursor=database.query(bookDBHelper.TABLE_LVS,colums,bookDBHelper.KEY_TYPE + " = \"" +bookDBHelper.TYPE_INDX + "\"",
            null,null,null,bookDBHelper.KEY_ID);
    if (cursor.moveToFirst()){
        do {
            season season = new season();
            season.setId(cursor.getLong(cursor.getColumnIndex(bookDBHelper.KEY_ID)));
            season.setStitle(cursor.getString(cursor.getColumnIndex(bookDBHelper.KEY_CONTENT)));
            season.setFav(cursor.getInt(cursor.getColumnIndex(bookDBHelper.KEY_ISFAV)) > 0);
            items.add(season);
        }while (cursor.moveToNext());

        }
    return items;
    }
    public void CopyDbfile()
    {
        try {
            InputStream in=this.context.getAssets().open("lvs.db");
            File dir=new File("/data/data/"+this.context.getPackageName()+"/databases");
            dir.mkdirs();
            FileOutputStream out=new FileOutputStream(new File(dir,"lvs.db"));
            byte[] buffer=new byte[1024];
            int len=0;
            while ((len=in.read(buffer))>0) {
                out.write(buffer, 0, len);

            }
            in.close();
            out.close();
            Log.i(LVSwitches.LOGTAG,"database copied");

        }
        catch (Exception e){
            Log.i("Story", "copy() : exception -> " + e.getMessage());
        }
    }



}

season class:

    public class season {

    private String stitle="";
    private String pic="";
    private long id=0;
    private boolean isFav=false;
    public season(String stitle){
        this.id= id;
        this.stitle= stitle;
        this.isFav= isFav;
    }

    public String getStitle() {
        return stitle;
    }

    public void setStitle(String stitle) {
        this.stitle = stitle;
    }

    public season()
    {
        String stitle="";
        String pic="";
        long id=0;
        boolean isFav=false;
    }


    public String getPic() {
        return pic;
    }

    public void setPic(String pic) {
        this.pic = pic;
    }

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public boolean isFav() {
        return isFav;
    }

    public void setFav(boolean fav) {
        isFav = fav;
    }
    public String toString(){
        return stitle;

    }
 }

You need to tell the ListView to use your data source. You can tell it to do so by writing

listView.setAdapter(YOUR_ADAPTER);

Just have a look at the Android documentation. Writing an adapter is well explained.

Furthermore, you mentioned the error that the application does too much work on its main thread. It does not have something to do with your ListView issue. It's much more a warning telling you to do heavy tasks on another Thread. The main thread is used to render your application. So if you do too much work on it your UI is blocked. I'd recommend you to do the database stuff on another thread. Moreover you should keep in mind that only the main thread can apply changes to the UI, so you might find the runOnUiThread() method of your activity object helpful when you want to do something with the result of your parallel thread's calculation on the UI thread.