fromHtml还有另一个重构：
fromHtml(String source, Html.ImageGetter imageGetter, Html.TagHandler tagHandler)

而ImageGetter imgGetter = new Html.ImageGetter() {
             @Override
             public Drawable getDrawable(String source) {
                   Drawable drawable = null;
                   drawable = Drawable.createFromPath(source);  // Or fetch it from the URL
                   // Important
                   drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable
                                 .getIntrinsicHeight());
                   return drawable;
             }
};

至于TagHandler，我们这里不需要使用，可以直接传null。

要让TextView解析和显示Html代码。可以使用
Spanned text = Html.fromHtml(source);
tv.setText(text);