从webview中加载assets中的html文件
private void readHtmlFormAssets(){
WebSettings webSettings = tipsWebView.getSettings();
webSettings.setLoadWithOverviewMode(true);
webSettings.setUseWideViewPort(true);
tipsWebView.setBackgroundColor(Color.TRANSPARENT);
tipsWebView.loadUrl("file:///android_asset/html/about.html");
}