Android ~ set WebView zoom button

mWebView = (WebView) findViewById(R.id.WebView01);

FrameLayout mContentView = (FrameLayout) getWindow().getDecorView().findViewById(android.R.id.content);
final View zoom = mWebView.getZoomControls();
mContentView.addView(zoom, ZOOM_PARAMS);
zoom.setVisibility(View.FOCUS_UP);

reference
http://www.tutorialforandroid.com/2009/02/webview-with-zoomcontrols-in-android.html