Android Developer Tip your project contains error (s), please fix them is

Once you've written your Android code with eclipse, the code doesn't get an error. And then

When you want to run a test in the AVD, the Error box always pops up with the message: " Your Project contains error (s), please fix them before running Your application.”
Whether restarting the AVD, restarting eclipse or even creating a new Android project will not work

There are several reasons:

1. Under different computer development, and file storage path is different, the main reason for the error is ". classpath" File loaded three-party class library package path error.

2. It is also possible that your SDK version does not exist or is not available.

3. There is a problem with the compiled class and APK file: Perform a clean-up. project→clean→clena Projects Selected below Select the item you have made a mistake.

4. It is possible that this is the most important point:in the program prompt box, you will be prompted to:"Error generating final archive:debug Certificate expired on12-7-25 7:52" Cause Analysis: Android requires that all programs must have a signature, otherwise the program will not be installed. In our development process, ADT uses the debug KeyStore, which is set in Preference->android->buid. The keystore of debug is valid for one year by default, and if you start the Android program a year ago, it is likely that the Debugkeystore expires when you import the app one year later, which prevents you from generating the apk file.   At this point you just delete the Debugkeystore, and the system will generate a private key for you that is valid for one year. Workaround: Enter C:\Documents and settings\administrator\.android to delete the Debug.keystore and ddms.cfg under the path. (Directories in different environments can be slightly different, find this path in eclipse: window->preferences->android->build default Debug KeyStore)