let loadingInstence
openLoading() {
loadingInstence = Loading.service({
lock: true,
text: '正在努力加载中...',
spinner: 'el-icon-loading',
background: 'rgba(0, 0, 0, 0.7)'
})
}
this.$nextTick(() => { // 以服务的方式调用的 Loading 需要异步关闭
loadingInstence.close()
})