code: public final void setDialogWindowBackground(@DrawableRes final int resourceId) {
          this.dialogWindowBackground = ContextCompat.getDrawable(getContext(), resourceId);
          this.dialogWindowBackgroundBitmap = null;
          this.dialogWindowBackgroundId = resourceId;
      }
docs: Sets the window background of the preference's dialog.
  
  @param resourceId
  The resource id, which corresponds to the window background, which should be set, as
  an {@link Integer} value. The resource id must correspond to a valid drawable
  resource