WEBVIEW

utilisez soit la librairie webview_flutter ou webview_flutter_plus

Exemples :

Flutter Load Local HTML File Placed in Assets Folder Example Tutorial

https://blog.codemagic.io/inappwebview-the-real-power-of-webviews-in-flutter/

Afin d’éviter l’erreur : ERR_CLEARTEXT_NOT_PERMITTED
Réference : https://stackoverflow.com/questions/55592392/how-to-fix-neterr-cleartext-not-permitted-in-flutter

Go to directory : my_flutter_project/android/app/src/main/res/

Create xml directory (in res!)

And inside xml add new file with name: network_security_config.xml and content:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <base-config cleartextTrafficPermitted="true">
        <trust-anchors>
            <certificates src="system" />
            <certificates src="user" />
        </trust-anchors>
    </base-config>
</network-security-config>

network_security_config.xml should be located in path: my_flutter_project/android/app/src/main/res/xml/network_security_config.xml

Go to:

flutter_project/android/app/src/main/AndroidManifest.xml

In main directory of your Flutter project you have three main folders:

- lib         =  your Dart code
- ios         =  generated structure for iOS platform
- android     =  generated structure for Android platform
We are interested in android directory. When you open it, you will see "typical Android app structure".

So you have to do 2 things:

1) Add new file in res
Go to directory:

my_flutter_project/android/app/src/main/res/
Create xml directory (in res!)

And inside xml add new file with name: network_security_config.xml and content:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <base-config cleartextTrafficPermitted="true">
        <trust-anchors>
            <certificates src="system" />
            <certificates src="user" />
        </trust-anchors>
    </base-config>
</network-security-config>
network_security_config.xml should be located in path: my_flutter_project/android/app/src/main/res/xml/network_security_config.xml

2) Modify AndroidManifest.xml
Go to: flutter_project/android/app/src/main/AndroidManifest.xml

AndroidManifest.xml is XML file, with structure:

<manifest>
    <application>
        <activity>
            ...
        </activity>
        <meta-data >
    </application>
</manifest>
So for <application> PROPERTIES you have to add 1 line:

android:networkSecurityConfig="@xml/network_security_config"

Références :

https://stackoverflow.com/questions/53831312/how-to-render-a-local-html-file-with-flutter-dart-webview