Question

I am working on a existing android project for my client. I have made some modification in his application. I am working on eclipse.

After sending the apk he installed it on his mobile but he has a complain that:

Current application failed install, even after it told me it was going to 
overwrite my old application information. Please remember to change keystore.

Let me know how can I change the keystore using eclipse so that it will not fail to install on his mobile. Please explain.

Thanks,
Pravin

Answer 1

Every .apk file should be signed with a key(by installing the SDK, you get a debug key). A key is unique and the system will check the key of an apk file if such a package has been installed in the device, to see if the key is the same as the existed one. If the key doesn’t match, the .apk file can’t be installed, unless you uninstalled the original one.

Now, I think you may have several choices:

1. sign the apk with your own key and ask you client to uninstall the old one.
2. sign the apk with your own key and change the package name.
3. get your client’s key and sign the apk with it.

For security reason, your client may not give his key to you. I think the best choice is to compile your project in release mode, and then ask your client to sign it with his private key. See here.