I have an error of null object reference. I cannot figure this out

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method ‘void android.widget.TextView.setText(java.lang.CharSequence)’ on a null object reference
at apps.fsc.foodtrackertuesday.MainActivity.printDatabase(MainActivity.java:63)
at apps.fsc.foodtrackertuesday.MainActivity.onCreate(MainActivity.java:33)

public class MainActivity extends AppCompatActivity {
EditText userEntryText;
TextView resultsText;
myDBManager dbManager;

protected void onCreate(Bundle savedInstanceState) {

    // Grab references to UI elements
    userEntryText = (EditText) findViewById(R.id.userEntryText);
    resultsText = (TextView) findViewById(R.id.resultsText);

    // dbManager reference
    dbManager = new myDBManager(this, null, null, 1);

    // Let's see what's in the database.

public void printDatabase() {
    // Query the database using the dbManager's dbToString() method.
    String dbString = dbManager.dbToString();

Textview and EditText are what is giving me errors. It crashes the app.