java - Xamarin Android : Cannot convert Java. IO.ByteArrayOutputStream 表达式类型 System.IO.Stream

Question

我正在使用 Xamarin Android 并在线“document.WriteTo(outPut);”我收到编译时错误。等效代码在 Java 中编译，但使用 Xamarin 和 c# 我遇到了某种类型的转换/转换问题。有谁知道如何解决这一问题？我想做的是将我创建的 pdf 转换为字节数组。

 Byte[] MakePDFFromImages(){
        // open a new document
        PrintAttributes printAttributes = new PrintAttributes.Builder().
            SetColorMode(Android.Print.PrintColorMode.Color).
            SetMediaSize(PrintAttributes.MediaSize.IsoA4).
            SetResolution(new PrintAttributes.Resolution("zooey","test", 450, 700)).
            SetMinMargins(PrintAttributes.Margins.NoMargins).
            Build();

        PrintedPdfDocument document = new PrintedPdfDocument (Activity.BaseContext, printAttributes);

        // start a page
        Android.Graphics.Pdf.PdfDocument.Page page = document.StartPage(0);

        ImageView imageView = new ImageView (Activity.BaseContext);
        imageView.SetImageBitmap (_imageArray [0]);

        imageView.Draw(page.Canvas);

        document.FinishPage(page);

        ByteArrayOutputStream outPut = new ByteArrayOutputStream();
        try {
            document.WriteTo(outPut);
            document.Close();
            outPut.Close();
        }
        catch(Exception){

        }

        return outPut.ToByteArray();
    }

Answer 1

PrintedPdfDocument.Write 需要 .NET Stream，而您传递给它的是 Java ByteArrayOutputStream。要修复，请使用 .NET MemoryStream:

    Byte[] MakePDFFromImages()
    {
        // open a new document
        PrintAttributes printAttributes = new PrintAttributes.Builder().
            SetColorMode(Android.Print.PrintColorMode.Color).
            SetMediaSize(PrintAttributes.MediaSize.IsoA4).
            SetResolution(new PrintAttributes.Resolution("zooey", "test", 450, 700)).
            SetMinMargins(PrintAttributes.Margins.NoMargins).
            Build();

        PrintedPdfDocument document = new PrintedPdfDocument(Activity.BaseContext, printAttributes);

        // start a page
        Android.Graphics.Pdf.PdfDocument.Page page = document.StartPage(0);

        ImageView imageView = new ImageView(Activity.BaseContext);
        imageView.SetImageBitmap(_imageArray[0]);

        imageView.Draw(page.Canvas);

        document.FinishPage(page);

        var outPut = new MemoryStream();
        try
        {
            document.WriteTo(outPut);
            document.Close();
            outPut.Close();
        }
        catch (Exception)
        {

        }

        return outPut.ToArray();
    }