[flutter] Flutter : Vertically center column

How to vertically center a column in Flutter? I have used widget "new Center". I have used widget "new Center", but it does not vertically center my column ? Any ideas would be helpful....

@override
Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(
      title: Text("Thank you"),
    ),
    body: new Center(
      child: new Column(
        children: <Widget>[
          new Padding(
            padding: new EdgeInsets.all(25.0),
            child: new AnimatedBuilder(
              animation: animationController,
              child: new Container(
                height: 175.0,
                width: 175.0,
                child: new Image.asset('assets/angry_face.png'),
              ),
              builder: (BuildContext context, Widget _widget) {
                return new Transform.rotate(
                  angle: animationController.value * 6.3,
                  child: _widget,
                );
              },
            ),
          ),
          new Text('We are glad we could serve you...', style: new TextStyle(
              fontSize: 16.0,
              fontWeight: FontWeight.w600,
              color: Colors.black87),),
          new Padding(padding: new EdgeInsets.symmetric(vertical: 5.0, horizontal: 0.0)),
          new Text('We appreciate your feedback ! !', style: new TextStyle(
              fontSize: 13.0,
              fontWeight: FontWeight.w200,
              color: Colors.black87),),
        ],
      ),
    ),
  );
}

You could use. mainAxisAlignment:MainAxisAlignment.center This will the material through the center in the column wise. `crossAxisAlignment: CrossAxisAlignment.center' This will align the items in the center in the row wise.

Container( alignment:Alignment.center, Child: Column () )

Simply use. Center ( Child: Column () ) or rap with Padding widget . And adjust the Padding such the the column children are in the center.

With Column, use:

mainAxisAlignment: MainAxisAlignment.center

It align its children(s) to center of its parent Space vertically

You control how a row or column aligns its children using the mainAxisAlignment and crossAxisAlignment properties. For a row, the main axis runs horizontally and the cross axis runs vertically. For a column, the main axis runs vertically and the cross axis runs horizontally.

 mainAxisAlignment: MainAxisAlignment.center,
 crossAxisAlignment: CrossAxisAlignment.center,

For me the problem was there was was Expanded inside the column which I had to remove and it worked.

Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: <Widget>[
            Expanded( // remove this
              flex: 2,
              child: Text("content here"),
            ),
          ],
        )

CrossAlignment.center is using the Width of the 'Child Widget' to center itself and hence gets rendered at the start of the page.

When the Column is centered within the page body's 'Center Container' , the CrossAlignment.center uses page body's 'Center' as reference and renders the widget at the center of the page

Code

import 'package:flutter/material.dart';

void main() => runApp(MaterialApp(
    title:"DynamicWidgetApp",
    home:DynamicWidgetApp(),

));

class DynamicWidgetApp extends StatefulWidget{
  @override
  DynamicWidgetAppState createState() => DynamicWidgetAppState();
  }

class  DynamicWidgetAppState extends State<DynamicWidgetApp>{
  @override
  Widget build(BuildContext context) {

    return Scaffold(
      body: Center(
     //Removing body:Center will change the reference
    // and render the widget at the start of the page 
        child: Column(
            mainAxisAlignment : MainAxisAlignment.center,
            crossAxisAlignment : CrossAxisAlignment.center,
            children: [
              Text("My Centered Widget"),
            ]
          ),
      ),
      floatingActionButton: FloatingActionButton(
        // onPressed: ,
        child : Icon(Icons.add),
      ),
      );
    }
  }

Another Solution!

If you want to set widgets in center vertical form, you can use ListView for it. for eg: I used three buttons and add them inside ListView which followed by

shrinkWrap: true -> With this ListView only occupies the space which needed.

import 'package:flutter/material.dart';

class List extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final button1 =
        new RaisedButton(child: new Text("Button1"), onPressed: () {});
    final button2 =
        new RaisedButton(child: new Text("Button2"), onPressed: () {});
    final button3 =
        new RaisedButton(child: new Text("Button3"), onPressed: () {});
    final body = new Center(
      child: ListView(
        shrinkWrap: true,
        children: <Widget>[button1, button2, button3],
     ),
    );

    return new Scaffold(
        appBar: new AppBar(
          title: Text("Sample"),
        ),
        body: body);
  }
}    
void main() {
  runApp(new MaterialApp(
    home: List(),
  ));
}

Output:

While using Column, use this inside the column widget :

mainAxisAlignment: MainAxisAlignment.center

It align its children(s) to the center of its parent Space is its main axis i.e. vertically

or, wrap the column with a Center widget:

Center(
  child: Column(
    children: <ListOfWidgets>,
  ),
)

if it doesn't resolve the issue wrap the parent container with a Expanded widget..

Expanded(
   child:Container(
     child: Column(
       mainAxisAlignment: MainAxisAlignment.center,
       children: children,
     ),
   ),
)

Try:

Column(
 mainAxisAlignment: MainAxisAlignment.center,
 crossAxisAlignment: CrossAxisAlignment.center,
 children:children...)

Try this one. It centers vertically and horizontally.

Center(
  child: Column(
    mainAxisAlignment: MainAxisAlignment.center,
    children: children,
  ),
)