ConstraintLayout layout;

        layout = new ConstraintLayout(this);
        if (matched.length == 0) {
            layout.setBackgroundResource(R.drawable.unsafe);
            setContentView(layout);
        }
        else{
            layout.setBackgroundResource(R.drawable.safe);
            setContentView(layout);
        }

java.lang.RuntimeException: Unable to start activity ComponentInfo{project.ca326.dcu.shoppingpal/project.ca326.dcu.shoppingpal.InformationActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference