ContentProvider can now lookup tracks via UUID.

src/main/java/de/dennisguse/opentracks/util/UUIDUtils.java

@@ -20,4 +20,19 @@ public class UUIDUtils {
         byteBuffer.putLong(uuid.getLeastSignificantBits());
         return byteBuffer.array();
     }
+
+    private static final char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray();
+
+    public static String toHex(@NonNull UUID uuid) {
+        byte[] bytes = toBytes(uuid);
+
+        char[] hexChars = new char[bytes.length * 2];
+        for (int i = 0; i < bytes.length; i++) {
+            int v = bytes[i] & 0xFF;
+
+            hexChars[i * 2] = HEX_ARRAY[v >>> 4];
+            hexChars[i * 2 + 1] = HEX_ARRAY[v & 0x0F];
+        }
+        return new String(hexChars);
+    }
 }