主要代码是：
// Use WideViewport and Zoom out if there is no viewport defined
settings.setUseWideViewPort(true);
settings.setLoadWithOverviewMode(true);
settings.setLayoutAlgorithm(LayoutAlgorithm.TEXT_AUTOSIZING);
另一个选项是启用压缩缩放：
// Enable pinch to zoom without the zoom buttons
settings.setBuiltInZoomControls(true);
if(Build.VERSION.SDK_INT > Build.VERSION_CODES.HONEYCOMB) {
// Hide the zoom controls for HONEYCOMB+
settings.setDisplayZoomControls(false);
}
