Dropbox is a very popular service, and with good reason. Not long ago I finally made the leap to the $99/year paid version that gives you 50GB of space instead of the 2-3GB in the free version, and ever since then I've been trying to get out of the "save space" mindset and use Dropbox fully. Dropsync is an app that helps with that, and does what Dropbox should be doing itself: provide two-way syncing on Android devices.
The official Dropbox app is nothing but a way to see the files in your Dropbox, upload and download them, as well as (with a recent update) automatically upload photos. "Nothing but" might sound ungrateful, but the core of Dropbox – the two way syncing – is missing in the official app. Dropsync on the other hand connects with your Dropbox account and allows you to not only have the entire Dropbox folder be automatically downloaded to your device (if you want to), but also do much more selective syncing.
One of the most obvious uses for this is what the official app can also do to some degree, namely handling your photos. If you have an expensive smartphone with a good camera, you're likely to use it. Dropsync allows you to set up syncing so that the entire DCIM (camera) folder on your device is synced to a folder in Dropbox. This also works with multiple devices, either to the same or different folders. That way you can have images you take on your phone not only show up on your computer, but in the camera folder on your tablet as well – if you want to. Personally, I set up four separate folders in the "Pictures" folder in my Dropbox: S II photos, S II screencapture, Galaxy Tab 7.0 Plus photos and Galaxy Tab 7.0 Plus screencapture. As the names imply, those folders are automatically synced with various folders on my Samsung Galaxy S II and Samsung Galaxy Tab 7.0 Plus, one for camera photos and one for screenshots – which I make a lot of while writing articles here and elsewhere. Take a screenshot on one of the devices, and it pops up in the corresponding folder.
There are many apps that does this on Google Play, but Dropsync also allows proper two-way syncing. That means that it will not just upload or download, but do both. This can be very useful for many things, for instance music. If you have a large music library and update it often, syncing music to your mobile device can be a pain. If you have the space on your Dropbox account, you can put your music folder in the Dropbox folder, and have Dropsync fetch music files for you and place them in your device's local music folder. You could then even spot duplicate files, delete them on your Android device, and have that change being synced back.
At this point in the article I'm sure people are experiencing mental screams along the lines of "battery life", "RAM", "mobile data costs" and so on. Those are very important points, which is why Dropsync has plenty of settings to decide exactly when a sync happens. Only on WiFi, only with files smaller than 20MB, automatically every 24 hours, instantly as new files are added, only on AC power, only when the battery capacity is at X% or more, and so on. The app itself is designed to be as low profile as possible as it does its magic in the background, which is even listed as a feature: "Compact code size, memory efficient, no fancy graphics, no useless animation. We have enough bloatware. Do one thing and do it best". Amen to that.
A small tip I can give to anyone who has many files to sync the first time is to set up the sync, connect the device to a PC, and transfer the files to the Dropbox folder manually. Then let your PC do the syncing, and then start the mobile device sync which makes it first look for the files (which it'll find) in the folder. That way you don't end up having to sync gigabytes of data over WiFi, while any future syncs will of course by on a much smaller scale.
The Dropsync app is free in the Google Play store, though the PRO version adds some features that you might end up needing to get much use out of this at all. It's priced at $6, which is high for an Android app, but still quite reasonable for what it does in my opinion.[Google Play]