Drag&Drop Support for Avalonia version on Android

[Genouka]

Which component should be improved?

UI/UX

Describe your feature suggestion in more detail

Merged from QiumingOrg/QiuUTMTv4#18

[Genouka]

At present, Avalonia does not have an official solution for drag and drop operations. I believe that feasible solutions include the following:

• Change the object box to searchable and filtered, allowing users to specify desired objects through input methods
• Research and modify the code related to Avalonia to support drag and drop (which is relatively complex)