code: public void setContentEmpty(boolean isEmpty) {
          ensureContent();
          if (mContentView == null) {
              throw new IllegalStateException("Content view must be initialized before");
          }
          if (isEmpty) {
              mEmptyView.setVisibility(View.VISIBLE);
              mContentView.setVisibility(View.GONE);
          } else {
              mEmptyView.setVisibility(View.GONE);
              mContentView.setVisibility(View.VISIBLE);
          }
          mIsContentEmpty = isEmpty;
      }
docs: If the content is empty, then set true otherwise false. The default content is not empty.
  You can't call this method if the content view has not been initialized before
  {@link #setContentView(android.view.View)} and content view not null.
  
  @param isEmpty true if content is empty else false
  @see #isContentEmpty()