When importing a project, about [2016-04-03 20:38:02-dex Loader] Unable to execute dex:multiple Dex files problem

Recently I was learning androidui design, found a UI menu interface open Source code example, follow the steps to import the project, run when the console results reported the following error:

[2016-04-03 20:38:02-dex Loader] Unable to execute Dex:multiple Dex files define Lcn/w/song/widget/navigation/rollnavigationbar$navigationbarlistener;
[2016-04-03 20:38:02-usewidgetdemo] Conversion to Dalvik format failed:unable to execute dex:multiple Dex files define Lcn/w/song/widget/navigation/rollnavi Gationbar$navigationbarlistener;

If I Baidu a bit, the reason is that there are duplicates, that is, the import jar package is duplicated. I looked at the jar package and I found myself importing one of the names for W.song.android.widget-1.0.4.jar two times, resulting in the project not working properly. So I deleted the W.song.android.widget-1.0.4.jar in the build path-configuration path, leaving only one W.song.android.widget-1.0.4.jar in the project. Runs successfully when the project is rerun.

Attached: I was at that time Baidu view URL: http://blog.csdn.net/penglijiang/article/details/38112511

When importing a project, about [2016-04-03 20:38:02-dex Loader] Unable to execute dex:multiple Dex files problem