关于一个点的问题（已解决）

Regarding the problem of a point not being displayed, I have found many solutions online, and they all say that we need to modify the source code, but I think that is quite troublesome. Here is my solution: I judge that if my list only has one value, I will dynamically add an empty data element (the value is negative), which is equivalent to two points, and the value of the second point is negative, so the second point will be drawn below the x-axis, so it cannot be seen. In other words, by default, a point is displayed with a line, and then dynamically determine to set the line to white.