I already answered a similar question (see Open PDF using PhoneGap in Android ), but will do the same here. Use the ChildBrowser plugin as suggested in conjunction with Google Docs, for example:
onclick='window.plugins.childBrowser.showWebPage(encodeURI("http://docs.google.com/viewer?url=' + pdfLink + '"));
This works great for me, and I tested it on Android 2.1 to 4.1.
Ian devlin
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