android - 通过在 recyclerview 的布局中设置 Checkox 的可见性“可见性”来关闭 recyclerView 时，应用程序崩溃

Question

错误是.................................................. ................. Java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法“android.view.View android.view.View.findViewById(int)”在 com.ABC.Fragment.NotificationFragment$2.onClick(NotificationFragment.java:192) ................... ………………………………………………………………………………………………………………………………………………

这是编辑文本视图上的可点击...

edit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                clicktype="clicktypeFromEdit";
                edit.setVisibility(View.GONE);
               done.setVisibility(View.VISIBLE);
                list_of_noti_pos.clear();
                list_of_noti_id.clear();
          
                for (int i = 0; i < notificationTypeList.size(); i++) {
                   //View v = notification_recyclerView.getLayoutManager().findViewByPosition(i);
                   View v = notification_recyclerView.getChildAt(i);
                    CheckBox cb = v.findViewById(R.id.checkbox);
                    LinearLayout ll_chk = v.findViewById(R.id.ll_chckbox);
                    ll_chk.setVisibility(View.VISIBLE);
                    cb.setVisibility(View.VISIBLE);
                    cb.setChecked(false);
                }