webview zoom

My application loads a webview, webview I increased the zoom, but now there is a function to zoom after the click of a button, the webview restored to the original size, I do not know how this should be achieved, ah, I now find that only the default webview You can click on the minus sign to zoom, but I ask for is about to be restored to the original point size, instead of clicking repeatedly<-! Main posts under Banner (D4) -><-! Posts under the main text (D5) ->
Reply:
I saw getScale method, you can get scale, had wanted to use this combination setScaleX and setScaleY to restore the size, but found that two methods are API 11 was introduced, but I use a minimum API set is 8, does not support these two methods
Reply:
Nobody knows?