App is crashing if try to add Image on Left or Right

[Maheshsmartdata]

Please check below exception
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setAlpha(float)' on a null object reference

When I use
cardStack.setRightImage(R.mipmap.ic_launcher);

[dimimall]

hello yes i faced the same problem have you any idea? how do i fix it?