Q:

flutter how to make a dynamic multi-column cupertinoPicker?

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In the gallery of flutter, there is a CupertinoDatePicker which can select multi-column, how to make a custom multi-column CupertinoPicker?
And is it possible make the CupertinoPicker be dynamic. For example, there are cities 2-D data(no need for async data, just an 2-D array). If I select a state, then the sub-column shows the cities in this state.
Thank you.

A:

Here is Github repo which contains basic Cupertino Widgets. It contains the MultiSelect Cupertino Picker and also with the action. 
Direct link of Cupertino Picker widget: https://github.com/dhuma1981/Flutter_Cupertino_Demo/blob/master/lib/ui/pages/picker_page.dart

