使用Android Studio从MySql检索变量

我只需要从mySql中检索一个东西，以便在Android Studio中使用，但它不起作用

代码如下：

public class MainActivity extends AppCompatActivity {
String driver = "com.mysql.jdbc.Driver";//driver a ser utilizado
String caminho = "jdbc:mysql://31.170.163.69/onbusonl_gestor";//camingo do driver, host e banco de dados
String usuario = "...";//usuario do postgre
String senha = "...";//senha do postgre
private String ConnectionResult;

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

    Connection conn;
    try{
        conn=DriverManager.getConnection(caminho,usuario,senha);
        String sql="select login from tb_login where login=1";
        PreparedStatement stm=conn.prepareStatement(sql);
        ResultSet rs=stm.executeQuery();

        if(rs.next()){
            Toast.makeText(MainActivity.this,"logou com sucesso",Toast.LENGTH_LONG).show();

        }
        else{
            Toast.makeText(MainActivity.this,"Não logado",Toast.LENGTH_LONG).show();
        }
    }catch (SQLException e){
        Toast.makeText(MainActivity.this,"erro",Toast.LENGTH_LONG).show();
    }
}

---

}

插入错误和代码，而不是屏幕图像。这样，人们就可以复制它并在开发环境中进行尝试