How to show a Dialog Box on a Button Click in Flutter?

In this post, I'm going to show you how to show a Dialog box on a Button Click.

import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.

  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  void _showcontent() {
    showDialog(
      context: context, barrierDismissible: false, // user must tap button!

      builder: (BuildContext context) {
        return new AlertDialog(
          title: new Text('You clicked on'),
          content: new SingleChildScrollView(
            child: new ListBody(
              children: [
                new Text('This is a Dialog Box. Click OK to Close.'),
              ],
            ),
          ),
          actions: [
            new FlatButton(
              child: new Text('Ok'),
              onPressed: () {
                Navigator.of(context).pop();
              },
            ),
          ],
        );
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text(widget.title),
      ),
      body: new Center(
        child: new Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            new Text(
              'Push the button to show a Dialog:',
            ),
            new RaisedButton(
              onPressed: _showcontent,
              color: Colors.blueAccent,
              child:
                  new Text('Click here', style: TextStyle(color: Colors.white)),
            ),
          ],
        ),
      ),
    );
  }
}

Let me know if this helps through your comments.