I always get java.lang.NoClassDefErrorFound : com.aspose.cells.workbook when i build my android project.
Thanks for your posting and using Aspose.Cells for Android.
Kindly check the aspose-cells-X.0.0.jar and bcprov-jdk5-146.jar libraries in the Order and Export tab inside the Java Build Path. It should fix your issue.
Please see the following screenshot for your reference.