When the orientation of app change this error is occur kindly help me
W/ActionBarDrawerToggle: DrawerToggle may not show up because NavigationIcon is not visible. You may need to call actionbar.setDisplayHomeAsUpEnabled(true);
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.explore_kpk, PID: 24892
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.explore_kpk/com.example.explore_kpk.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.recyclerview.widget.RecyclerView.setLayoutManager(androidx.recyclerview.widget.RecyclerView$LayoutManager)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3256)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3352)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5389)
at android.app.ActivityThread.access$1200(ActivityThread.java:223)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1803)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7231)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
***Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.recyclerview.widget.RecyclerView.setLayoutManager(androidx.recyclerview.widget.RecyclerView$LayoutManager)' on a null object reference***
***at com.example.explore_kpk.MainActivity.onCreate(MainActivity.java:121)
at android.app.Activity.performCreate(Activity.java:6877)***
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1136)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3209)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3352)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5389)
at android.app.ActivityThread.access$1200(ActivityThread.java:223)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1803)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7231)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
I/Process: Sending signal. PID: 24892 SIG: 9
This is code in which error pointing**
at com.example.explore_kpk.MainActivity.onCreate(MainActivity.java:121)
RecyclerView recyclerView=(RecyclerView)findViewById(R.id.recyler_view);
RecyclerViewAdapter recyclerViewAdapter = new RecyclerViewAdapter(this, recyclerList);
long seed = System.nanoTime();
Collections.shuffle(recyclerList, new Random(seed));
GridLayoutManager gridLayoutManager=new GridLayoutManager(this, mNoOfColumns);
recyclerView.setLayoutManager(gridLayoutManager);
recyclerView.setAdapter(recyclerViewAdapter);