WebView App crashes when clicking on Data Table Plugin export button

Hi i have a website using Data Tables plugin to show and export data in different formats like excel, csv and pdf. The website is running perfectly fine and buttons to export is also working. Now i have created WebView for the website, but whenever i click the export buttons from Data Tables plugin, the app crashes. I have given android downloader and permissions and have attached some screenshots of the code.
Using JQuery for Data Tables creation in website.

Plugin

code Jquery datatable implement

code webview

code webview android downloader.

I am new to webview creation, so can you also explain the issue and solution. I want the android webview to work perfectly fine, the buttons to download the data exactly like in my website.