How can I remove the white background in a webview?

I have the following problem: I am loading a html file into a webview. The background color of my html file and my activity is black. What happens is that there is a short white flash at the beginning when finished loading because the background color of the webview is white.

Can I remove that flash? Or set that webview color to black? I already tried setting the background color in the webview xml to black, but it didn't work.