Nrthugu

This is my layout xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:app="http://schemas.android.com/apk/res-auto"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:background="@color/fragment_body"

android:fitsSystemWindows="true">



<include

    android:id="@+id/contextToolBar"

    layout="@layout/context_toolbar_layout" />



<android.support.v7.widget.RecyclerView

    android:id="@+id/list1"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:layout_below="@+id/contextToolBar"

    android:scrollbarSize="5dp"

    android:scrollbarThumbVertical="@color/scrollbarColor"

    android:scrollbars="vertical"

    app:layout_behavior="@string/appbar_scrolling_view_behavior" />



<ProgressBar

    android:id="@+id/delete_progress"

    style="@style/Widget.AppCompat.ProgressBar"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:layout_centerHorizontal="true"

    android:layout_centerVertical="true"

    android:visibility="gone" />

It displays a grid of images in the recyclerview.
I can select a bunch of images & have an option to delete them.
The following is the delete logic:

public void deleteSelectedFiles(final Context context, final List<MediaModel> selectionList) {



    String confirmationMessage = getString(R.string.delete_confirm_message);



    new AlertDialog.Builder(context)

            .setTitle(getString(R.string.action_delete))

            .setMessage(confirmationMessage)

            .setIcon(android.R.drawable.ic_dialog_alert)

            .setPositiveButton(android.R.string.yes, (dialog, whichButton) -> {

                View progressBar = getActivity().findViewById(R.id.delete_progress);

                dialog.cancel();

                progressBar.setVisibility(View.VISIBLE);



                deleteFileList(selectionList, this.getActivity());



                progressBar.setVisibility(View.GONE);

            })

            .setNegativeButton(android.R.string.no, null).show();

}

I am expecting the progress bar to display in the foreground while the delete operation is going on. But it just doesn't show up. Any help would be highly appreciated.