add web vieew in flutter code example

Example: add web view in flutter

A Flutter plugin that provides a WebView widget.

On iOS the WebView widget is backed by a WKWebView; On Android the WebView widget is backed by a WebView.

Usage 
Add webview_flutter as a dependency in your pubspec.yaml file.

You can now include a WebView widget in your widget tree. See the WebView widget's Dartdoc for more details on how to use the widget.

Android Platform Views 
The WebView is relying on Platform Views to embed the Android’s webview within the Flutter app. By default a Virtual Display based platform view backend is used, this implementation has multiple keyboard. When keyboard input is required we recommend using the Hybrid Composition based platform views implementation. Note that on Android versions prior to Android 10 Hybrid Composition has some performance drawbacks.

Using Hybrid Composition 
To enable hybrid composition, set WebView.platform = SurfaceAndroidWebView(); in initState(). For example:

import 'dart:io';

import 'package:webview_flutter/webview_flutter.dart';

class WebViewExample extends StatefulWidget {
  @override
  WebViewExampleState createState() => WebViewExampleState();
}

class WebViewExampleState extends State<WebViewExample> {
  @override
  void initState() {
    super.initState();
    // Enable hybrid composition.
    if (Platform.isAndroid) WebView.platform = SurfaceAndroidWebView();
  }

  @override
  Widget build(BuildContext context) {
    return WebView(
      initialUrl: 'https://flutter.dev',
    );
  }
}
SurfaceAndroidWebView() requires API level 19. The plugin itself doesn't enforce the API level, so if you want to make the app available on devices running this API level or above, add the following to <your-app>/android/app/build.gradle:

android {
    defaultConfig {
        // Required by the Flutter WebView plugin.
        minSdkVersion 19
    }
  }