public void setMuPDFView(int page)
        {
            if (_core == null)
            {
                return;
            }

            // Now create the UI.
            // First create the document view
            mDocView = new MuPDFReaderView(this);
            mAdapter = new MuPDFPageAdapter(this, _core);
            mDocView.SetAdapter(mAdapter);
            mDocView.DisplayedViewIndex = page;


            // Stick the document view and the buttons overlay into a parent view

            if (mPDFView != null)
            {
                try
                {
                    mPDFView.AddView(mDocView);
                }
                catch (Exception e)
                {
                    Console.WriteLine(e + "     <===========");
                }
            }
        }
        private void ClearPDF()
        {
            if (mDocView != null)
            {
                DisposeReaderView();
                mDocView.Dispose();
                mPDFView.Dispose();
                mAdapter.ReleaseBitmaps();
                mAdapter.Dispose();


                if (_core != null)
                {
                    _core.OnDestroy();
                    _core.Dispose();
                    _core    = null;
                    mAdapter = null;
                    mDocView = null;
                    mPDFView = null;
                }
            }
        }