Previous Android project error, new Android project errors, the code can not find the wrong solution

Opened a year ago, the results found that the Android project in all have a red fork, can not find errors. Create a new project also error, first determine their own environment should be OK, and then by looking at the information on the Internet, it is possible that the debug keystore expired.

Through the online information guide, do the following:

1, enter C:\Documents and settings\administrator\.android delete path under the Debug.keystore and Ddms.cfg (I only deleted the Debug.kestore can also.) online say two are deleted).
(Directories in different environments can be slightly different, find this path in eclipse: window->preferences->android->build default Debug KeyStore)
2, enter eclipse,project---->clean can solve the problem successfully.

Specific analysis:

You need to have a signature in your Android program. In general, ADT uses the debug KeyStore during the development process. You can set its path through Preference->android->buid. The KeyStore of debug is typically one year old, and if you are a one-year-old Android program, it is likely that it is now out of date, causing the program to not run. But why is the new program not working because it uses the KeyStore under the same path. Therefore, the debug keystore needs to be removed, allowing the system to regenerate the new keystore for you.

Previous Android project error, new Android project errors, the code can not find the wrong solution