mui原生底部选项卡实现（图片+文字）

manifest.json代码：

"launchwebview": {"bottom": "0px","background": "#fff","subNViews": [{"id": "tabBar","styles": {"bottom": "0px","left": "0","height": "75px","width": "100%","backgroundColor": "#fff"},"tags": [{"tag": "img","id": "indexIcon","src": "images/mipmap-xhdpi/icon_message.png","position": {"top": "9px","left": "13%","width": "36px","height": "36px"}}, {"tag": "font","id": "indexText","text": "消息","position": {"top": "47px","left": "0","width": "33%","height": "24px"},"textStyles": {"align": "center","size": "15px"}},{"tag": "img","id": "newsIcon","src": "images/mipmap-xhdpi/icon_friend.png","position": {"top": "9px","left": "46%","width": "36px","height": "36px"}}, {"tag": "font",