Re-installation failed Zxing import to Android project

I had import to my project the example of Zxing for Android Application. I dont have errors and when i try to run on device, the console give this output:

[2011-08-26 20:57:06 - CaptureActivity] Re-installation failed due to different application signatures.
[2011-08-26 20:57:06 - CaptureActivity] You must perform a full uninstall of the application. WARNING: This will remove the application data!
[2011-08-26 20:57:06 - CaptureActivity] Please execute 'adb uninstall com.google.zxing.client.android' in a shell.
[2011-08-26 20:57:06 - CaptureActivity] Launch canceled

I try to execute the adb command in shell but give me "permission den开发者_如何转开发ied". Before i never have this app in my phone, sometimes with this error i uninstall app from device, run again and works but at this time i dont know what i can do. any suggestion?

You have a copy of Barcode Scanner installed from the Market. You are installing your app under the same name and package. For security reasons, Android does not allow you do to this, since you have not signed the app in the way we have of course.

You would need to uninstall Barcode Scanner first. If you can't, it is perhaps not uninstallable since it is pre-installed on the phone.

However, the problem is that you are trying to create an application using our package and our app name. In fact I assume you have mostly copied our source code. We do not find this acceptable. Please write your own application. If you need to re-use pieces of ours, that's OK -- it's open source. But it is not OK to copy and paste it so much as you are doing here.