可绘制文本不可见

Question

我正在尝试在可绘制对象上插入文本。 到目前为止的代码是这样的：

Bitmap markerBitmap = Utils.getBitmapFromVectorDrawableWithText(this, R.drawable.ic_pickup_marker, "Some address");
            LatLng pickupPoint = new LatLng(Double.parseDouble(parcelListItem.pickupPointLatitude), Double.parseDouble(parcelListItem.pickupPointLongitude));
            mMap.addMarker(new MarkerOptions().icon(BitmapDescriptorFactory.fromBitmap(markerBitmap)).position(pickupPoint).title("Pickup Point"));

使用 getBitmapFromVectorDrawable 方法。

public static Bitmap getBitmapFromVectorDrawableWithText(Context context, int drawableId, String drawableText){
        Drawable drawable = ContextCompat.getDrawable(context, drawableId);

        Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
                drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);

        Paint paint = new TextPaint(TextPaint.ANTI_ALIAS_FLAG);
        paint.setStyle(Paint.Style.FILL);
        paint.setColor(Color.WHITE);
        paint.setTextSize(30);
        paint.setTextAlign(Paint.Align.CENTER);

        canvas.drawText(drawableText, bitmap.getWidth()/2, bitmap.getHeight() /2, paint );

        drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
        drawable.draw(canvas);

        return bitmap;
    }

我不明白为什么这不起作用。 最终结果如下所示：

我想在那个drawable中间放一些白色的文字。 我怎么做？