我之前遇到过类似的问题，我***更新（在您的情况下，焦点），使用Vue的 nextTick 方法，该方法将立即使用已经更改了一些数据以等待DOM更新。：

I encountered a similar problem before, and I forced the update (in your case, the focus) by using Vue's nextTick method, which is to use immediately after you’ve changed some data to wait for the DOM update.:

this.$nextTick(() => {
    this.$refs.questionInput.focus();
})