title: How to retrieve integer data from SQLite and show it in textview?
body: <p>I'm new in SQLite and I have this code that shows the points in textview which retrieves the data from the database and if I click the button, it should retrieve the data, add some integers and append it to the database. However whenever I run the app, the app crashes.</p>
  
  <p>Here's my mainActivity</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>import android.widget.TextView;
  
  public class MainActivity extends Activity {
  
    DatabaseHelper mydb;
    private static TextView txt_stars;
  
    @
    Override
    protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
  
      mydb = new DatabaseHelper(this);
      onButtonClickListener();
      txt_stars = (TextView) findViewById(R.id.txtStars);
      //I already clean my code here
    }
  
    public void onButtonClickListener {
  
      button_next = (Button) findViewById(R.id.btnNext);
      button_next.setOnClickListener(
        new View.OnClickListener() {
        @Override
          public void onClick(View v) {
            AlertDialog.Builder alert = new AlertDialog.Builder(context);
            alert.setMessage("You have earned 50 stars");
            alert.setCancelable(false);
            alert.setPositiveButton("next", new DialogInterface.OnClickListener() {
              public void onClick(DialogInterface dialog, int whichButton) {
                //retrieve data, add 50, append data and return to main with a textview of 50 stars. How do I do this?
              }
            });
            AlertDialog alertDialog = alert.create();
            alertDialog.show();
          }
        }
      );
  
    }
  
  
  }</code></pre>
  </div>
  </div>
  </p>
  
  <p>Here's my DatabaseHelper.java</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>import android.content.ContentValues;
  import android.content.Context;
  import android.database.Cursor;
  import android.database.sqlite.SQLiteDatabase;
  import android.database.sqlite.SQLiteOpenHelper;
  
  
  public class DatabaseHelper extends SQLiteOpenHelper {
  
    public static final String DATABASE_NAME = "star.db";
    public static final String TABLE_NAME = "stars_table";
    public static final String COL1 = "stars";
  
  
    public DatabaseHelper(Context context) {
      super(context, DATABASE_NAME, null, 1);
  
    }
  
    @Override
    public void onCreate(SQLiteDatabase db) {
      db.execSQL("create table" + TABLE_NAME + "(" + COL1 + ")");
  
    }
  
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
      db.execSQL("DROP TABLE IF EXISTS" + TABLE_NAME);
      onCreate(db);
    }
  
    public boolean insertData(Integer stars) {
      SQLiteDatabase db = this.getWritableDatabase();
      ContentValues contentValues = new ContentValues();
      contentValues.put(COL1, stars);
      long result = db.insert(TABLE_NAME, null, contentValues);
      if (result == -1)
        return false;
      else
        return true;
    }
  
    public Cursor getAllData() {
      SQLiteDatabase db = this.getWritableDatabase();
      Cursor res = db.rawQuery("select stars from" + TABLE_NAME, null);
      return res;
    }
  
  }</code></pre>
  </div>
  </div>
  </p>
  
  <p>Thanks a lot!</p>