uni-app setTabBarBadge在非tabBar页面设置时无法生效

getters:{
		// 商品总量
		goodsCount(state){
			let num = 0
			num = state.shoppingCart.reduce((count,current) => {
				if(current.select && !state.outIdList.find(i => i == current.spuId)) {
					return num += current.quantity
				}else {
					return num
				}
			},num)
			console.log('num',num);
			return num
		}
	}

watch:{
			goodsCount:{
				handler(newGoodCount,oldGoodCount){
					console.log('触发监听',newGoodCount);
					let that = this
					uni.setTabBarBadge({ //显示红点
						index: 2 ,//tabbar下标
						text:newGoodCount+'',
					})
					if(newGoodCount == 0) {
						uni.hideTabBarRedDot({
							index:2
						})
					}
				},
				immediate:true
			}
		},

onShow(){
    this.updateBadge()
},
updateBadge(){
				if(this.goodsCount > 0) {
					uni.setTabBarBadge({ //显示红点
						index: 2 ,//tabbar下标
						text:this.goodsCount+'',
					})
				}
				if(this.goodsCount == 0) {
					uni.hideTabBarRedDot({
						index:2
					})
				}
			},