StribogECG is an open source ECG viewer under GPL v3. It uses biosig library (C) to read some ECG dara formats - scp, xml(hl7), ecg, gdf. You should download files on your "downloads" diractory (which is on sdcard) and then you can open them. Or you can check our test server. StribogECG was tested with mentioned above file formats, and all issues I found I fixed.