I want to get a content page from Wiki in this format (the picture below) then show it in WebView. It means the content includes text and links.

I tried this but the output seems to be messy.
http://en.wikipedia.org/w/api.php?action=query&prop=revisions&rvprop=content&titles=Albert_Einstein&format=xmlfm
You want
index.php?action=render; an example. This returns the HTML of the page content with no sidebar/header/footer HTML. You’ll have to match and remove infoboxes yourself.Reference: MediaWiki — Manual:Parameters to index.php.