How to figure out there are missing activities, in Android manifest file, with Eclipse?

I've seen a number of people have problems because they don't add the activity to the manifest file. I've suffered from this myself.

This seems like such a simple/common problem yet I have no clue how I'm supposed to figure that out from the Eclipse IDE.

Is the debugging output of Eclipse totally useless开发者_如何学Go or is there something I'm missing?

You can actually find that out if you're viewing logcat in the DDMS-tab of Eclipse. If you haven't added it, it throws an ActivityNotFoundException or similar exception, and even asks if one remembered to add the actitivy to the manifest.