I am new to android development, and I have been using the command line tools to create an android project. I followed all the instructions given in the tutorial at android
Your project is missing the support library from the SDK.
If you have no installed them, just right click on the project > Android Tools > Install support library.
Then, just import into workspace, as an Android project, android-support-v7-appcompat, located into ${android-sdk-path}/extras/android/support/v7
And finally, right click in the Android project > Properties > Android Tab. Push the Add button and add the support project "android-support-v7-appcompat" as dependency.
Clean your project and the must compile and work properly.