如何在android中将PdfDocument对象保存到文件中？

在我的应用程序中，我在按钮点击事件中创建了一个PDF文档。我使用了打印框架打印该文档。所有这些都工作正常。我需要的是，我想将该PDF文档保存到手机存储器中的文件夹中。如何做，我不知道如何将该PDF保存到文件中。有人能帮我吗？谢谢

我的代码生成一个pdf

public class CustomPrintActivity extends Activity {





@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.fragment_custom_print);
}



public void printDocument(View view)
{
    PrintManager printManager = (PrintManager) this
            .getSystemService(Context.PRINT_SERVICE);

    String jobName = this.getString(R.string.app_name) +
            " Document";

    printManager.print(jobName, new MyPrintDocumentAdapter(this),
            null);
}
public class MyPrintDocumentAdapter extends PrintDocumentAdapter {
    Context context;
    private int pageHeight;
    private int pageWidth;
    public PdfDocument myPdfDocument;
    public int totalpages = 1;


    public MyPrintDocumentAdapter(Context context) {
        this.context = context;
    }

    @Override
    public void onLayout(PrintAttributes oldAttributes,
                         PrintAttributes newAttributes,
                         CancellationSignal cancellationSignal,
                         LayoutResultCallback callback,
                         Bundle metadata) {


        myPdfDocument = new PrintedPdfDocument(context, newAttributes);

        pageHeight =
                newAttributes.getMediaSize().getHeightMils() / 1000 * 72;
        pageWidth =
                newAttributes.getMediaSize().getWidthMils() / 1000 * 72;

        if (cancellationSignal.isCanceled()) {
            callback.onLayoutCancelled();
            return;
        }

        if (totalpages > 0) {
            PrintDocumentInfo.Builder builder = new PrintDocumentInfo
                    .Builder("print_output.pdf")
                    .setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT)
                    .setPageCount(totalpages);

            PrintDocumentInfo info = builder.build();
            callback.onLayoutFinished(info, true);
        } else {
            callback.onLayoutFailed("Page count is zero.");
        }
    }


    @Override
    public void onWrite(final PageRange[] pageRanges,
                        final ParcelFileDescriptor destination,
                        final CancellationSignal cancellationSignal,
                        final WriteResultCallback callback) {

        for (int i = 0; i < totalpages; i++) {
            if (pageInRange(pageRanges, i)) {
                PdfDocument.PageInfo newPage = new PdfDocument.PageInfo.Builder(pageWidth,
                        pageHeight, i).create();

                PdfDocument.Page page =
                        myPdfDocument.startPage(newPage);

                if (cancellationSignal.isCanceled()) {
                    callback.onWriteCancelled();
                    myPdfDocument.close();
                    myPdfDocument = null;
                    return;
                }
                drawPage(page, i);
                myPdfDocument.finishPage(page);

            }
        }

        try {
            myPdfDocument.writeTo(new FileOutputStream(
                    destination.getFileDescriptor()));

      /*   String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/cookbook";

            File dir = new File(path);
            if(!dir.exists())
                dir.mkdirs();

            Log.d("PDFCreator", "PDF Path: " + path);


            File file = new File(dir, "recipe.pdf");
            FileOutputStream fOut = new FileOutputStream(file);
            myPdfDocument.writeTo(fOut);

            FileWriter fw = new FileWriter(file.getAbsoluteFile());
            BufferedWriter bw = new BufferedWriter(fw);
            bw.write(myPdfDocument);
            bw.close();*/


        } catch (IOException e) {
            callback.onWriteFailed(e.toString());
            return;
        } finally {
            myPdfDocument.close();
            myPdfDocument = null;
        }

        callback.onWriteFinished(pageRanges);

    }

    private boolean pageInRange(PageRange[] pageRanges, int page) {
        for (int i = 0; i < pageRanges.length; i++) {
            if ((page >= pageRanges[i].getStart()) &&
                    (page <= pageRanges[i].getEnd()))
                return true;
        }
        return false;
    }

    private void drawPage(PdfDocument.Page page,
                          int pagenumber) {
        Canvas canvas = page.getCanvas();

        pagenumber++; //

        int titleBaseLine = 90;
        int leftMargin = 50;

        /*Drawable icon = getResources().getDrawable(R.drawable.pot);
        icon.setBounds(leftMargin - 40, 40, 60, 80);
        icon.getIntrinsicHeight();
        icon.getIntrinsicWidth();

        icon.draw(canvas);*/


        Paint paint = new Paint();
        paint.setColor(Color.BLACK);

        paint.setTextSize(18);
        Typeface fontRegular = Typeface.createFromAsset(getAssets(), "Roboto-Regular.ttf");

        paint.setTypeface(fontRegular);
        canvas.drawText("PDF SAMPLE", leftMargin, titleBaseLine, paint);
        paint.setTextSize(14);
        canvas.drawText("PDF LINE NO 1", leftMargin, titleBaseLine + 30, paint);

        paint.setTextSize(12);
        canvas.drawText("PDF LINE NO 1", leftMargin, titleBaseLine + 50, paint);

        paint.setTextSize(14);
        canvas.drawText("PDF LINE NO 1", leftMargin, titleBaseLine + 80, paint);

        paint.setTextSize(12);
        canvas.drawText("PDF LINE NO 1", leftMargin, titleBaseLine + 100, paint);


    }
}



}

公共类CustomPrintActivity扩展活动{
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.fragment\u custom\u print）；
}
公共作废打印文档（视图）
{
PrintManager PrintManager=（PrintManager）此
.getSystemService（Context.PRINT_服务）；
String jobName=this.getString（R.String.app\u name）+
“文件”；
printManager.print（作业名，新的MyPrintDocumentAdapter（此），
无效）；
}
公共类MyPrintDocumentAdapter扩展了PrintDocumentAdapter{
语境；
私人网页高度；
私有int页面宽度；
公共PDF文档MyPDF文档；
公共int totalpages=1；
公共MyPrintDocumentAdapter（上下文）{
this.context=上下文；
}
@凌驾
public void Only布局（打印属性oldAttributes，
打印属性newAttributes，
取消信号取消信号，
LayoutResultCallback回调，
捆绑包（元数据）{
myPdfDocument=新打印的PDFDocument（上下文，新属性）；
页高=
newAttributes.getMediaSize（）.getHeightMils（）/1000*72；
页面宽度=
newAttributes.getMediaSize（）.getWidthMils（）/1000*72；
if（cancellationSignal.isCancelled（））{
callback.onLayoutCancelled（）；
返回；
}
如果（总页数>0）{
PrintDocumentInfo.Builder=新的PrintDocumentInfo
.Builder（“print_output.pdf”）
.setContentType（PrintDocumentInfo.CONTENT\u TYPE\u文档）
.setPageCount（总页数）；
PrintDocumentInfo=builder.build（）；
callback.onlayoufinished（info，true）；
}否则{
callback.onlayoufailed（“页面计数为零”）；
}
}
@凌驾
写入时公共无效（最终页面范围[]页面范围，
最终包裹描述符目的地，
最终取消信号取消信号，
最终写入结果（回调）{
对于（int i=0；i=pageRanges[i].getStart（））&&
（第页）使用这种方法

 public void saveFile( String fileName, PdfDocument document) {

     try {

            File mypath=new File( Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS),"filename.pdf");
            document.writeTo(new FileOutputStream(mypath));

            document.close();

        }