Is it enable to keep the origin visible X Range when I appended more data

[aelam]

For example

1. a DataSet with XIndex from 0 to 100, Set axis Range like below then I can see all data in Chart

 _chartView.xAxis.axisMinimum = 0;
 _chartView.xAxis.axisMaximum = 100;

2. I append a group of data with XIndex from -100 to -1 to this DataSet. Then I change the XAxis Range like the below

 _chartView.xAxis.axisMinimum = -100;
 _chartView.xAxis.axisMaximum = 100;

here is the problem
If I change axisMinimum, axisMaximum like the step 2, I can zoom in/out, move left/right. But I lost the origin visible range
If I don't change I can keep the origin visible range, but the data from -100 to -1 won't be enable to scroll to be seen.

My current solution is keeping the origin axisMinimum, axisMaximum the origin values , when I scroll the chart, I change the axisMinimum, axisMaximum at the same time to keep the xAxisRange not changed.

I'm wondering if the best way is modify the matrix in the step 2 ?
I also notice that there are two not used ivar. are they used to track the origin position?

    fileprivate var _autoScaleLastLowestVisibleX: Double?
    fileprivate var _autoScaleLastHighestVisibleX: Double?

[liuxuan30]

I feel that you changed the data, and then change the chart property, and then you should call notifyDataSetChanged(), or you should set axisMaximum and then update the data to make sure the calculation reflect correctly. That's because setting data should call notifyDataSetChanged() automatically.

Can this solve your issue?

[aelam]

The main point is move to the origin place after appended points. I've tried like the step 2 and moveView and it works. I hope I am using the API correctly