title: Why Row is not horizantally center inside a Column
body: <p>As we know by default,<strong>Column horizontally</strong> center its children if it has full width.But when i placed two cards and one row inside a column,two cards are placed horizontally center by flutter but <strong>row remains same</strong> at its start position? Why?<br/>
  I think <strong>row should be horizontally center</strong> because it is a child of Column in my case but it's not.</p>
  <pre><code>Widget build(BuildContext context) {
      return Scaffold(
        appBar: AppBar(
          title: Text('Flutter App'),
        ),
        body: Container(
          color: Colors.purple,
          height: double.infinity,
          child: Column(
            //  mainAxisAlignment: MainAxisAlignment.center,
            //  crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              Card(
                child: Text(
                  'Chart',
                  style: TextStyle(fontSize: 20.0),
                ),
                elevation: 5,
                color: Colors.blue,
              ),
              Card(
                child: Text(
                  'list of tx',
                  style: TextStyle(
                    fontSize: 20.0,
                  ),
                ),
                color: Colors.purple,
              ),
              Row(
                children: [
                  Text('this is row'),
                ],
              ),
            ],
          ),
        ),
      );
    }
  }
  
  
  
  </code></pre>
  <p><a href="https://i.stack.imgur.com/Hv73w.png" rel="nofollow noreferrer">output of this code</a></p>