I follow this tutorial https://glyphsapp.com/tutorials/creating-an-apple-color-font
Finally, I successfully made the .svg file but the files I found were empty.
So I found that it is not empty, but my character is in the corner of the picture, so that I can’t see it when I open the file.
I don’t know what error occurred in the process caused this result to happen.
How to position the image is described in that tutorial in the section ‘Controlling Width, Scale and Position’.
And how do you test the font? This might also be a font cache problem. Read this please:
http://www.glyphsapp.com/tutorials/eliminating-font-cache-problems
Also make sure you the latest beta of Glyphs. Go to Glyphs > Preferences > Updates, activate both checkboxes and press the Update button.
If you open the .svg it might look strange. That has to do with the coordinate system of SVG.