WebView.draw() not properly working on latest Android System WebView Update

Question

I'm currently using WebView.draw() to take a screenshot of the entire WebView and save it into a Bitmap (based off of this solution). It has worked perfectly up until now.

I was recently testing this functionality on a Nexus 5 (please note that on the Nexus 5 the WebView in question is bigger than the screen, so the user can scroll both horizontally and vertically) running Lollipop 5.1 and the latest update of Android System WebView (version 42.0.2311.137 at time of writing) when I noticed that the generated bitmap was wrong. It had the correct dimensions but instead of showing the whole WebView, it only had the part of the WebView that was visible to the user when the method was called.

I have tried uninstalling all updates to the Android System WebView (thus bringing it back to version 39 (1743759-arm) and with the factory version the functionality works fine. So this problem is due to a relatively recent update of the Android System WebView. I wasn't able to find a change log so I can't figure out what has changed and how to fix it. Below is a quick visual explanation:

Has anyone else encountered this problem and found a possible solution ?

Answer 1

You need to call WebView.enableSlowWholeDocumentDraw() before creating any WebViews. That is, if you have any WebViews in your layout, make sure you call this method before calling setContentView() in your onCreate().