This app can track your work time easily! It lets you categorize each recorded interval by a client/task and a free text. Of course, the list of clients/tasks can be edited to suit your needs.
Additionally, if you wish, your flexible time account is taken care of: you always see how much you worked. You can also keep an eye on how much work time is left for today (by a notification which you can enable).
You even may provide the geo-coordinates or the Wi-Fi network name of your work place and the app can automatically clock you in while you are at work! This is done without using GPS, so your battery won't be emptied by this app.
If you prefer to use other apps like Llama or Tasker for tracking your movements, that's fine - TWT can be triggered from these apps and just do the book-keeping of your work time. You just have to create broadcast intents called org.zephyrsoft.trackworktime.ClockIn or org.zephyrsoft.trackworktime.ClockOut. When using ClockIn, you can also set the parameters task=... and text=... in the "extra" section of the intent so your events are more meaningful. Here are some screenshots to point out how it can be done: Llama: Overview, Detail 1, Detail 2 / Tasker: Detail 1, Detail 2.
If you like, the app can backup its data on Google's servers using Android's standard mechanism. But it's always up to you - if you don't enable it actively, it won't happen!
Finally, the app can generate reports for you. The raw events report is the right thing if you want to import your data somewhere else, while year/month/week reports are fine if you want to keep track of your task progress.
This is an open source project, so if there is something you don't like, you are very welcome to contact me or even write some code yourself and contribute it. Please don't try to communicate with me via reviews on Google Play or AndroidPit, that doesn't work in both directions. Just write me an email, and I'll see what I can do.
You can track the past development by looking at the version history.
Links to binary distribution points:
And finally, some technical stuff (which is only interesting if you are a developer, I suppose):
project tracker (JIRA)
continuous integration server (Jenkins)
You can obtain the source code easily via Subversion (SVN). If you have a UNIX-like OS, SVN is possibly already installed. In this case execute the following command in the directory where you want the sources to go to:
svn co https://dev.zephyrsoft.org/svn/projects/trackworktime/trunk trackworktime
If you are running a different OS, refer to your SVN client's manual (list of SVN client programs).