[final Widget? childWidget;[ is declaring an optional instance variable
[childWidget[ of type [Widget[. This variable can be used to pass a child
widget to the [InAppWebView[ widget, which can be displayed alongside the
[WebView[ widget. The [?[ after the type [Widget[ indicates that the variable
can be [null[.
[final String? from;[ is declaring an optional instance variable [from[ of
type [String[. The [?[ after the type [String[ indicates that the variable can
be [null[. This variable can be used to pass a string value to the
[InAppWebView[ widget, which can be used to identify the source of the web
page being loaded in the [WebView[. It is not being used in the code provided
and can be removed if not needed.
[final Function(String) onCancel;[ is declaring an instance variable
[onCancel[ of type [Function[ that takes a single argument of type [String[.
This variable is passed as a required parameter to the [InAppWebView[
constructor and is used to handle the cancellation of the WebView. When the
cancel button is pressed, the [_handleNavigation[ function is called with an
empty string as the argument, which in turn calls the [onCancel[ function
passed to the constructor with the argument ['Success'[. This allows the
parent widget to handle the cancellation event and perform any necessary
actions.
[final Function(bool, Object) onError;[ is declaring an instance variable
[onError[ of type [Function[ that takes two parameters: a [bool[ and an
[Object[. This variable is used to pass a callback function to the
[InAppWebView[ widget that will be called when an error occurs during the
loading of a web page in the WebView. The [bool[ parameter indicates whether
the error is a network error or not, and the [Object[ parameter contains
additional information about the error. The callback function can be used to
handle the error in a custom way, such as displaying an error message to the
user or logging the error for debugging purposes.
[final bool? showHome;[ is declaring an optional instance variable [showHome[
of type [bool[. The [?[ after the type [bool[ indicates that the variable can
be [null[. This variable can be used to determine whether to show a home page
or not in the [InAppWebView[ widget. However, it is not being used in the code
provided and can be removed if not needed.
[final String? url;[ is declaring an optional instance variable [url of type
[String[. The [?[ after the type [String[ indicates that the variable can be
[null[. This variable can be used to pass a URL string to the [InAppWebView[
widget, which can be loaded in the [WebView[. If no URL is provided, the
[WebView[ will not load any page.
