Null pointer exception when parent view became visible

[devslava]

My app has a RelativeLayout as a parent of HorizontalPicker. It has INVIZIBLE or GONE visibility value at application startup. When I make RelativeLayout visible in my application, app crashes with Null Pointer exception . Is it a bug or I am doing something wrong?

java.lang.NullPointerException at com.wefika.horizontalpicker.HorizontalPicker.remakeLayout(HorizontalPicker.java:382) at com.wefika.horizontalpicker.HorizontalPicker.calculateItemSize(HorizontalPicker.java:863) at com.wefika.horizontalpicker.HorizontalPicker.onSizeChanged(HorizontalPicker.java:452) at android.view.View.sizeChange(View.java:14953) at android.view.View.setFrame(View.java:14926) at android.view.View.layout(View.java:14834) at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1055) at android.view.View.layout(View.java:14838) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453) at android.widget.FrameLayout.onLayout(FrameLayout.java:388) at android.view.View.layout(View.java:14838) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:1043) at android.view.View.layout(View.java:14838) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453) at android.widget.FrameLayout.onLayout(FrameLayout.java:388) at android.view.View.layout(View.java:14838) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671) at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525) at android.widget.LinearLayout.onLayout(LinearLayout.java:1434) at android.view.View.layout(View.java:14838) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453) at android.widget.FrameLayout.onLayout(FrameLayout.java:388) at android.view.View.layout(View.java:14838) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671) at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525) at android.widget.LinearLayout.onLayout(LinearLayout.java:1434) at android.view.View.layout(View.java:14838) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453) at android.widget.FrameLayout.onLayout(FrameLayout.java:388) at android.view.View.layout(View.java:14838) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1996) at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1753) at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1005) at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5750) at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761) at android.view.Choreographer.doCallbacks(Choreographer.java:574) at android.view.Choreographer.doFrame(Choreographer.java:544) at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747) at android.os.Handler.handleCallback(Handler.java:733) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5017) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) at dalvik.system.NativeStart.main(Native Method)

BTW, I am adding values programmatically by setValues() method.