希望能将midButton的高亮、selectIcon设置问题解决一下

pages.json  
{  
    "pages": [ //pages数组中第一项表示应用启动页，参考：https://uniapp.dcloud.io/collocation/pages  
        {  
            "path": "pages/home/index",  
            "style": {  
                "navigationBarTitleText": "home"  
            }  
        },  
        {  
            "path": "pages/message/index",  
            "style": {  
                "navigationBarTitleText": "message"  
            }  
        },  
        {  
            "path": "pages/publish/index",  
            "style": {  
                "navigationBarTitleText": "publish"  
            }  
        },  
        {  
            "path": "pages/order/index",  
            "style": {  
                "navigationBarTitleText": "order"  
            }  
        },  
        {  
            "path": "pages/mine/index",  
            "style": {  
                "navigationBarTitleText": "mine"  
            }  
        }  
    ],  
    "globalStyle": {  
        "navigationBarTextStyle": "black",  
        "navigationBarTitleText": "uni-app",  
        "navigationBarBackgroundColor": "#F8F8F8",  
        "backgroundColor": "#F8F8F8"  
    },  
    "tabBar": {  
        "color": "#7A7E83",  
        "selectedColor": "#007aff",  
        "borderStyle": "black",  
        "backgroundColor": "#ffffff",  
        "midButton": {  
            "width": "80px",  
            "height": "60px",  
            "text": "发布",  
            "iconPath": "",  
            "iconWidth": ""  
        },  
        "list": [  
            {  
                "pagePath": "pages/home/index",  
                "text": "首页",  
                "iconPath": "",  
                "selectedIconPath": ""  
            },  
            {  
                "pagePath": "pages/order/index",  
                "text": "订单",  
                "iconPath": "",  
                "selectedIconPath": ""  
            },  
            // #ifdef H5 || APP-PLUS  
            {  
                "pagePath": "pages/publish/index",  
                "text": "发布",  
                "iconPath": "",  
                "selectedIconPath": "",  
                "visible": false  
            },  
            // #endif  
            // #ifdef H5 || APP-PLUS  
            {  
                "pagePath": "pages/publish/index",  
                "text": "发布",  
                "iconPath": "",  
                "selectedIconPath": "",  
                "visible": false  
            },  
            // #endif  
            {  
                "pagePath": "pages/message/index",  
                "text": "消息",  
                "iconPath": "",  
                "selectedIconPath": ""  
            },  
            {  
                "pagePath": "pages/mine/index",  
                "text": "我的",  
                "iconPath": "",  
                "selectedIconPath": ""  
            }  
        ]  
    },  
    "uniIdRouter": {}  
}  

App.vue  
      export default {  
        onLaunch: function() {  
            console.log('App Launch')  
            uni.onTabBarMidButtonTap(() => {  
                console.log('点击了中间的按钮')  
                uni.setTabBarStyle({  
                    // index: 2,    //这里如果能单独设置就好了  
                    selectedColor: "#7A7E83",  
                    color: '#007aff'  
                })  
                uni.switchTab({  
                    url: '/pages/publish/index'  
                })  
            })  
        },  
        onShow: function() {  
            console.log('App Show')  
        },  
        onHide: function() {  
            console.log('App Hide')  
        }  
    }