Android Studio Value Callback <Uri>

ValueCallback is a callback interface that is used to provide values asynchronously, as a literal translation of the Android document. Used to process the file dialog (=file upload) in WebView. I think it would be helpful to understand if you look at the examples that are actually used. Please check the link below.

Following the code is for processing the file Uri selected in the file dialog to the Web view via the onReceiveValue(Uri) function in ValueCallback.

OnCreateWindow() is a function called when a function window.open() is called in JavaScript. That is, it can be understood as a callback function that is invoked when a new window (pop-up that you encounter in your PC web environment) is displayed in the web view. See the link below for examples of similar use.