Android app debugging no problem, but packaged with a signed apk, what happens when the runtime flashes?

When using Eclipse to write Android app, sometimes debugging is not a problem, but once the package signed, run a flash, also reported wrong to find that class. At first I thought it was confusing, and then I didn't get confused and it was still the problem. Helpless had to find solutions on the Internet, and finally someone solved, the method is very simple, just follow the following steps to be able to:

1. Locate project--build automatically, and cancel it to turn off automatic compilation
2. Then clean it up a bit.
3. Finally in the manual build

Then you pack your signature so you can run it properly.

Android app debugging no problem, but packaged with a signed apk, what happens when the runtime flashes?