How to write exif data to image in Android?

Question

I'm trying to write a User_Comment and TAG_GPS to a captured image in an Android application using the exif interface, but for some reason the tags don't seem to be appended to the image when I view the image's details in the gallery.

It seems that maybe the tags are not being written to the captured image as the file path may be wrong. I think it could be because I've written the tags to an incorrect image path.

Does anyone know if their is a problem with the way I'm writing the tags to the image?

This is the code that saves the exif data following @Charlie's changes below:

private File getOutputPhotoFile() throws IOException {
          File directory = new File(Environment.getExternalStoragePublicDirectory(
                        Environment.DIRECTORY_PICTURES), getPackageName());
          if (!directory.exists()) {
            if (!directory.mkdirs()) {
              Log.e(TAG, "Failed to create storage directory.");
              return null;
            }
          }


          String timeStamp = new SimpleDateFormat("yyyMMdd_HHmmss", Locale.ENGLISH).format(new Date());

          File[] files = directory.listFiles();

          File exifVar =  new File(directory.getPath(), "IMG_" + timeStamp + ".jpg");
          if(files.length!=0) {
              File newestFile = files[files.length-1];
              exifVar =  new File(directory.getPath() + File.separator + newestFile.getName());
          }

          String mString = "Generic Text..";     
          ExifInterface exif = new ExifInterface(exifVar.getAbsolutePath());
          exif.setAttribute("UserComment", mString);
          exif.saveAttributes();


          exif.setAttribute(ExifInterface.TAG_GPS_LATITUDE,
            String.valueOf(latituteField.toString()));

          exif.setAttribute(ExifInterface.TAG_GPS_LONGITUDE, 
            String.valueOf(longitudeField.toString()));

          exif.saveAttributes();

          return exifVar; 




    }

Answer 1

You need first to copy the exif files located here google exif to your project, then use the following code :

    ExifInterface exif = new ExifInterface();
    exif.readExif(exifVar.getAbsolutePath());
    exif.setTagValue(ExifInterface.TAG_USER_COMMENT, mString);
    exif.forceRewriteExif(exifVar.getAbsolutePath())); 

ExifInterface used here is the new one you've just added.