you have to make the choice regarding webview or intent. just to make sure you understand,
you cannot load a pdf file from a local file into a webview.
if you are determined to use a webview, you also have to remember to be online to download the pdf the first time. what happens if you cannot get online?
what happens if the server is down? if you download the pdf right now from your desktop browser and copy it to your assets folder, then you can use it whenever you want without being online. you just can't use a webview. you have to use a pdf viewer.
if you are determined to use a webview, then you need add the
webviewsettings library to your project. choose the setcachemode method and use
"LOAD_CACHE_ELSE_NETWORK". this
should let you load the resource the first time and then use the cached resource. webview is a strange beast; there is no guarantee it does what the documentation says it's supposed to do. you will have to try it. it is my understanding that the cache will be cleared when your app is killed by the os (or when you turn your device off). you will need to try things. think hard; you will figure out how to tell if the pdf is downloading each time
if you use okhttputils2 to download the file (a perfectly fine course of action), it will not help you for loading into a webview. you will have to use the saved copy with an intent. mc73 is suggesting you download from the app, i'm suggesting you just download the file now and copy it to your assets folder. the end result is the same: you will have the pdf saved, but you can't use it with a webview. you have to get that idea out of your head.