iText PDF字体不会发生变化。卢比符号未显示

我正在使用iText PDF在Android中创建PDF文件。我需要在PDF中写入'$'符号。我有以下代码： -iText PDF字体不会发生变化。卢比符号未显示

public static final String FONT1 = "/main/assets//PlayfairDisplay-Regular.ttf"; 
public static final String FONT2 = "/main/assets/PT_Sans-Web-Regular.ttf"; 
public static final String FONT3 = "/main/assets/FreeSans.ttf"; 
public static final String RUPEE = "The Rupee character \u20B9 and the Rupee symbol \u20A8";

这些被声明为类变量。我有一个函数createPDF（）写入PDF文档。我的代码在功能上以下行： -

File pdfFile = new File(filePath); 
    OutputStream output = new FileOutputStream(pdfFile); 
    Document document = new Document(PageSize.A4); 
    PdfWriter.getInstance(document, output); 
    document.open(); 
    Font f1 = FontFactory.getFont(FONT1, BaseFont.IDENTITY_H, BaseFont.EMBEDDED, 12); 
    Font f2 = FontFactory.getFont(FONT2, BaseFont.IDENTITY_H, BaseFont.EMBEDDED, 12); 
    Font f3 = FontFactory.getFont(FONT3, BaseFont.IDENTITY_H, BaseFont.EMBEDDED, 12); 
    Font f4 = FontFactory.getFont(FONT3, BaseFont.WINANSI, BaseFont.EMBEDDED, 12); 
    document.add(new Paragraph(RUPEE, f1)); 
    document.add(new Paragraph(RUPEE, f2)); 
    document.add(new Paragraph(RUPEE, f3)); 
    document.add(new Paragraph(RUPEE, f4)); 
    document.close();

然而无论是字体被反映在PDF也不卢比符号。我的PDF看起来如下： -

Resulting PDF