Easy way to do it there. If you are not afraid of difficulties, then scrFramework7 screen is an example.
Thank you, I already had a look i need a bit more time until I fully understand the example.
I have two additional questions, maybe you can help me to understand the possibilities of thunkable a bit better.
I know i can upload a html file and open it localy in Thunkabel, if i upload compiled Bootstrap and java files, will i be able to access them aswell through the uploaded html file?
If you need a two-way communication between the App and WebViewer, it can be done only with the help of my solutions above. It does not matter where the html-file, there is in him Bootstrap or something else. It is important to only one thing - the presence of the html-file code to write data to Firebase.
If you need a one-way communication, and more specifically the generation of HTML-code, it can be done with the help of Data URI (does not work on iOS installed applications). These examples also have in my sample project, for example, on the scrCanvas or scrHTML.
Functionality WebViewer has some differences from the system browser functionality on Android and iOS, for this reason, there may be cases that the html-page works well in the system browser, but it has some peculiarities in the WebViewer.