In order to use "Theme.AppCompat" in my project I created a separate library project named "android-support-v7-appcompat" and included this.
However, the theme cannot be resolved, although I exactly followed the steps as described in Adding libraries with resources on Android Developers.
What went wrong?
Maybe the project cannot be resolved correctly, because if I open the dialog "Properties" on my project again and select the tab "Android" I get the following (see last picture) ...