);

WebView showing ERR_CLEARTEXT_NOT_PERMITTED ?

Open the android manifest file (android/app/src/main/AndroidManifest.xml) and add

android:usesCleartextTraffic="true"

to the application tag

<application
        android:name="io.flutter.app.FlutterApplication"
        android:label="tangerine_ui"
        android:icon="@mipmap/ic_launcher"
        android:usesCleartextTraffic="true">