Eclipse: "Activity not started" error

Sometimes when I make a change to a source file in Eclipse开发者_开发技巧 (3.7.0) and Run | Run, the emulator gets loaded with the update and everything is fine.

Other times, I get the standard launch messages, then one last one in red:

ActivityManager: Warning: Activity not started, its current task has been brought to the front

and it appears that the program did not get updated

I don't know what I'm doing different between the two cases. Any ideas?

TIA!

---

This happens when there are no changes in the code / resources. Then all the Android plugin does is start the app which was already installed in the previous time you ran it.

If you're changing images or any resource / code outside the IDE, don't forget to refresh the project's contents before building.