Widgets 17 | SimpleDialog

In this tutorial, you will learn how to use the SimpleDialog in the flutter.

What we will learn?

Before Start

We will create a page to contain our code.

import "package:flutter/material.dart";
import 'package:flutter_widgets/const/_const.dart';

class SimpleDialogPage extends StatefulWidget {
  @override
  _DialogState createState() => _DialogState();
}

class _DialogState extends State<SimpleDialogPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(PageName.SIMPLE_DIALOG),
      ),
      body: SingleChildScrollView(
        child: Column(
          children: <Widget>[
            SizedBox(height: 600),
          ],
        ),
      ),
    );
  }
}

It will show the picture as follows.

Simple Use

The dialog is very common in our app, it will show short messages to us to our choice. Let's see an example below.

SimpleDialog(
              title: Text("What we do?"),
              children: [
                Text("This is our tutorial about the SimpleDialog."),
              ],
            ),

It will show you like this.

Constructor

Let's look at its constructor.

SimpleDialog({
    Key key,
    this.title,
    this.titlePadding = const EdgeInsets.fromLTRB(24.0, 24.0, 24.0, 0.0),
    this.children,
    this.contentPadding = const EdgeInsets.fromLTRB(0.0, 12.0, 0.0, 16.0),
    this.backgroundColor,
    this.elevation,
    this.semanticLabel,
    this.shape,
  })

The constructor is very easy to know because we have known the types of its parameters. I will give an example to them.

titlePadding&contentPadding

The title is a widget, the children is a list of the widgets, this is easy to understand. The titlePadding controls the padding of the title, the contentPadding controls the padding of the children. Let's see an example.

 Widget _padDialog() => SimpleDialog(
        title: Text(
          "Do you know why?",
          textAlign: TextAlign.center,
        ),
        titlePadding: EdgeInsets.symmetric(
          horizontal: 30,
          vertical: 20,
        ),
        children: <Widget>[
          Text(
            "Sometime,we learn very well,because we want to it.",
            textAlign: TextAlign.center,
          )
        ],
        contentPadding: EdgeInsets.symmetric(
          horizontal: 40,
          vertical: 20,
        ),
      );

Let's see the effect of our code.

backgroundColor& elevation

The backgroundColor is a Color, the elevation controls the shadow of the widget, those are common parameters that we have used them before. I just give an example.

  Widget _colorDialog() => SimpleDialog(
        title: Text(
          "Message",
          textAlign: TextAlign.center,
        ),
        children: <Widget>[
          Text(
            "You must learn it carefully.",
            textAlign: TextAlign.center,
          ),
        ],
        backgroundColor: RED,
        elevation: 4,
      );

It will show like this. The color of the background will change to RED.The shadow becomes less.

shape

The is also the same as the shape of Container, you can check it in that article. I just give you an example.

 Widget _shapeDialog() => SimpleDialog(
        title: Text(
          "Be careful!",
          textAlign: TextAlign.center,
        ),
        children: <Widget>[
          Text(
            "If you write a message, you should care about the message.",
            textAlign: TextAlign.center,
          ),
        ],
        backgroundColor: BLUE_LIGHT,
        elevation: 4,
        shape: StadiumBorder(
          side: BorderSide(
            style: BorderStyle.none,
          ),
        ),
      );

It will show as below.

Conclusion

From this article, you can learn how to implement the dialog with the SimpleDialog widget. It is easy to use, so I don't give the detail of many parameters. If you a newer, you should read the other articles before.

Thanks for your reading!

The end.