如何将“样式文本”从我的应用程序发送到Whatsapp？

Question

我在互联网上到处搜索，但是没有找到任何文档来将样式化的文本从我的应用程序发送到Whatsapp。

这是我用来通过意图将文本从应用程序发送到Whatsapp的代码：

String s = list.get(index);
            SpannableStringBuilder SS = new SpannableStringBuilder(s);
            int length = s.length();
            SS.setSpan (new CustomTypefaceSpan("", custom_font), 0, length-1,Spanned.SPAN_EXCLUSIVE_INCLUSIVE);

            Intent whatsappIntent = new Intent(Intent.ACTION_SEND);
            whatsappIntent.setType("text/plain");
            whatsappIntent.setPackage("com.whatsapp");
            whatsappIntent.putExtra(Intent.EXTRA_TEXT, SS);
            try {
                ctx.startActivity(whatsappIntent);
            } catch (android.content.ActivityNotFoundException ex) {
                Toast.makeText(ctx, "Whatsapp is not installed!", Toast.LENGTH_SHORT).show();
            }

这是CustomTypefaceSpan类：

public class CustomTypefaceSpan extends TypefaceSpan {

private final Typeface newType;

public CustomTypefaceSpan(String family, Typeface type) {
    super(family);
    newType = type;
}

@Override
public void updateDrawState(TextPaint ds) {
    applyCustomTypeFace(ds, newType);
}

@Override
public void updateMeasureState(TextPaint paint) {
    applyCustomTypeFace(paint, newType);
}

private static void applyCustomTypeFace(Paint paint, Typeface tf) {
    int oldStyle;
    Typeface old = paint.getTypeface();
    if (old == null) {
        oldStyle = 0;
    } else {
        oldStyle = old.getStyle();
    }

    int fake = oldStyle & ~tf.getStyle();
    if ((fake & Typeface.BOLD) != 0) {
        paint.setFakeBoldText(true);
    }

    if ((fake & Typeface.ITALIC) != 0) {
        paint.setTextSkewX(-0.25f);
    }

    paint.setTypeface(tf);
}

}

它仅发送纯文本，而未应用样式。 预先感谢。