title: What is causing the errors in the following java code
body: <p>I have implemented a method to validate a user against an SQLite DB but the program keeps throwing an error when the login button is clicked  the error codes follow </p>
  
  <blockquote>
    <p>2019-04-15 21:38:27.455 4601-4601/com.example.mymedicare
    E/AndroidRuntime: FATAL EXCEPTION: main
        Process: com.example.mymedicare, PID: 4601
        android.database.sqlite.SQLiteException: no such column: Brad (code 1): , while compiling: SELECT * FROM users WHERE Brad =? AND
    Brad1994 =?
            at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native
    Method)
            at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
            at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
            at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
            at android.database.sqlite.SQLiteProgram.(SQLiteProgram.java:58)
            at android.database.sqlite.SQLiteQuery.(SQLiteQuery.java:37)
            at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
            at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1318)
            at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1257)
            at com.example.mymedicare.MyDBHelper.checkLogin(MyDBHelper.java:96)</p>
  </blockquote>
  
  <p>I have tried reading the error log but can't find any serious errors my methods will be shown below </p>
  
  <pre><code>  // This is my check login method in mydbhelper   
  
     public boolean checkLogin(String username, String password) {
      SQLiteDatabase db = this.getWritableDatabase();
  
      String s;
      Cursor c = db.rawQuery("SELECT * FROM users WHERE " + username + " =? AND " + password + " =?", null);
  
      if (c.getCount() &lt;= 0) {
          c.close();
          db.close();
          return false;
      } else {
          c.close();
          db.close();
          return true;
      }
  }
  
  
     //This is LoggingIn activity where I have tried to implement the above 
     method 
  
     public class LoggingIn extends AppCompatActivity {
  
  //defines page objects
  private Button SignIn;
  private EditText Usernames;
  private EditText Passwords;
  private MyDBHelper db;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_logging_in);
  
      //Finds objects by ID
       //edit text to string
      Usernames = (EditText) findViewById(R.id.Usernames);
  
      Passwords = (EditText) findViewById(R.id.Passwords);
  
  
      Button SignIn = (Button) findViewById(R.id.SignIn);
      db = new MyDBHelper(this);
  
      SignIn.setOnClickListener(new Button.OnClickListener() {
          @Override
          public void onClick(View v) {
              Boolean validUser = 
       db.checkLogin(Usernames.getText().toString(), 
       Passwords.getText().toString());
  
              if (validUser == true) {
                  Intent i = new Intent(getApplicationContext(), 
                  HomePage.class);
                  startActivity(i);
              } else {
                  Toast.makeText(getApplicationContext(), "Invalid login", 
                  Toast.LENGTH_SHORT).show();
              }
  
          }
      });
  }
  }
  </code></pre>