App crash when trying to rescan media player.

PROJECT INFO
https://github.com/souch/SMP

EXPECTED BEHAVIOR
When the users click rescan button it should be able to rescan media player with well and correctly.

ACTUAL BEHAVIOR
When the users click on rescan media player then the app has stopped and getting crashed.

HOW TO REPRODUCE
●Install SicMu player on playstore
●open the app and go to setting button
●click advanced settings
●Next,click on rescan media player
●then the app getting crash.
Browser: SicMu player version: 1.2
Device: android 7.0

RECORDING BUG

PROOF OF WORK DONE
https://github.com/souch/SMP/issues/42
github.com/dzami

LOGCAT

Process: souch.smp, PID: 23948
java.lang.NullPointerException: Attempt to get length of null array
    at souch.smp.Path.listFiles(Path.java:211)
    at souch.smp.Settings.scanMediaFiles(Settings.java:279)
    at souch.smp.Settings.rescan(Settings.java:245)
    at souch.smp.Settings.onPreferenceClick(Settings.java:236)
    at android.preference.Preference.performClick(Preference.java:990)
    at android.preference.PreferenceScreen.onItemClick(PreferenceScreen.java:214)
    at android.widget.AdapterView.performItemClick(AdapterView.java:305)
    at android.widget.AbsListView.performItemClick(AbsListView.java:1163)
    at android.widget.AbsListView$PerformClick.run(AbsListView.java:3181)
    at android.widget.AbsListView.onTouchUp(AbsListView.java:4008)
    at android.widget.AbsListView.onTouchEvent(AbsListView.java:3773)
    at android.view.View.dispatchTouchEvent(View.java:8484)
    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2432)
    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2103)
    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2438)
    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2132)
    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2438)
    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2132)
    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2438)
    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2132)
    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2438)
    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2132)
    at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2424)
    at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1768)
    at android.app.Dialog.dispatchTouchEvent(Dialog.java:789)
    at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2385)
    at android.view.View.dispatchPoint```