family finance (v1.55) app crash when change view by in report section

PROJECT INFORMATION

• repositories : https://github.com/zwieback/FamilyFinance
• issues : https://github.com/zwieback/FamilyFinance/issues/1

EXPECTED BEHAVIOR

when the user changes the appearance of the report from "view value" to "use percent value" this application will still work properly and will display report data in accordance with the wishes of the user

ACTUAL BEHAVIOR

when the user changes the appearance of the report from "view value" to "use percent value" this application will crash and stop working

STEPS TO REPRODUCE

• install and open the app
• click "report" option
• scroll to the right side to "incomes by articles or expenses by articles
• click eye icon
• change view by "view values" to "use percent values"
• see errors
  devices
• phone models: oppo neo 7
• os : android 6.1

BUG RECORDING

logcat

Process: io.github.zwieback.familyfinance, PID: 13191
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.github.mikephil.charting.data.PieData.setDrawValues(boolean)' on a null object reference
    at io.github.zwieback.familyfinance.business.chart.fragment.PieChartFragment.onApplyDisplay(PieChartFragment.java:160)
    at io.github.zwieback.familyfinance.business.chart.fragment.PieChartFragment.onApplyDisplay(PieChartFragment.java:40)
    at io.github.zwieback.familyfinance.business.chart.activity.ChartActivity.onApplyDisplay(ChartActivity.java:150)
    at io.github.zwieback.familyfinance.business.chart.dialog.ChartDisplayDialog.lambda$onCreateDialog$0(ChartDisplayDialog.java:53)
    at io.github.zwieback.familyfinance.business.chart.dialog.-$$Lambda$ChartDisplayDialog$3JuCWsAV3m9zaJu55iVYBsSndyU.onClick(lambda)
    at android.support.v7.app.AlertController$ButtonHandler.handleMessage(AlertController.java:167)
    at android.os.Handler.dispatchMessage(Handler.java:111)
    at android.os.Looper.loop(Looper.java:218)
    at android.app.ActivityThread.main(ActivityThread.java:5657)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:990)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:785)```