<p>If subfolder "icon" exists, then files named as "0","1","2"...<br>
are used for icons in the bottom toolbar. file "0" to replace the left arrow button, "1" for right arrow button, "2" for the setting button,"3" for the home screen button,...</p>
<p>If a new button is defined (file name "20" exists), uweb also supports VectorDrawable with "android compiled XML" format. All icon files must be all VectorDrawables or 此时所有图标文件必须都是compiled XML格式,或都是普通的图像格式(png,jpg,gif等)。用户可将VectorDrawable XML文件放到安卓项目目录assets下面,重新生成apk文件以后将apk文件解压即可得compiled XML格式图标文件。</p>