Debugging of my app is now suddenly broken. It has been fine up to now and I even reloaded a known good version of my entire code and it still fails to debug or even run.
On your Android device (or emulator) go to:
Applications - Settings - Applications - Manage applications - All
There you have to select your app and uninstall it.
Afterwards try to run your app from the IDE again. It should work now.
Create a new debug configuration of type Remote Java Application
and set it to localhost and the port you see on the DDMS window.
https://stackoverflow.com/a/13421917/624109