Question

In my app I have a dbhelper class where everything in my database happens, I know I have to use the onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) but I’m having problems on understanding how do I call it if I’m not updating the complete application, all I want is that in the internet call finds that I have change the version in my web table to drop tables in my app and rebuild them so it could get the new information.
Here is my code:

In my bd helper:

public class CuestionarioHelper extends SQLiteOpenHelper {

private static String DB_PATH = "/data/data/myapp.VerCuestionarioEspanol_copy/databases/";
private static final String DB_NAME="cuestionario.db";
private static final int SCHEMA_VERSION=1;
private SQLiteDatabase myData; 
public CuestionarioHelper(Context context) {
    super(context, DB_NAME, null, SCHEMA_VERSION);
}   
@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE Version (_id INTEGER PRIMARY KEY AUTOINCREMENT, version TEXT);");
    db.execSQL("CREATE TABLE Cuestionario (_id INTEGER PRIMARY KEY AUTOINCREMENT, pregunta TEXT, respuesta TEXT);");
    }
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS " + "Version");
    db.execSQL("DROP TABLE IF EXISTS " + "Cuestionario");
    onCreate(db);
}

and in my mainActivity:

private CuestionarioHelper db = null;

 @Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

   db = new CuestionarioHelper(this);

// here in a  class DownloadFileAsync extends AsyncTask<String, String, String> 
  I download the version of the table in the web and if is different than the one 
  already in the db then it calls the table complete information to replace the one 
  in the apps db.

//Here I verify what table version I have so I can add to a non existing table, 
  do nothing if both versions are the same or replace the bd table if they are different.

public void verficar(){

verify = db.getTableCount();
if(verify == 0){
    tvVersion.setText("Version nueva "+Version.get(0).version);
    // download the table information and added to the db
}else{
    if(versionEntrada.equals(db.getVersion())){
        tvVersion.setText("Version ya existe "+db.getVersion());
           //version is the same do nothing
    }else{
        int oldVersion = Integer.parseInt(db.getVersion());
        int newVersion = Integer.parseInt(versionEntrada);
        db.onUpgrade(db, oldVersion, newVersion);//here is where I don't know 
                                                    //how to call it, this is not working!
        // download the table information and added to the db
        tvVersion.setText("Version actualizada "+Version.get(0).version);
    }
}
}

In the db the Version table is where I store the table version or it could be the db version it only has one column and one row since it will be just one number to compare to my web table version.

Answer 1

You should make your SCHEMA_VERSION not final and pass this version as a parameter:

change these lines

private static final int SCHEMA_VERSION=1;
public CuestionarioHelper(Context context) {
    super(context, DB_NAME, null, SCHEMA_VERSION);
}   

to (notice that SCHEMA_VERSION is removed)

public CuestionarioHelper(Context context, int version) {
    super(context, DB_NAME, null, version);
}