Charts on android emulator

when I use a chart component the Android emulator throws the following exception:

Error from Companion: java.lang.NoClassDefFoundError: com.github.mikephil.charting.charts.Chart$1

All other compnents function properly but the chart is not shown.

Anyone?

Update Companion in the emulator.

Download the latest Companion from the Help - Companion information menu. Drag the downloaded APK file onto the running emulator.