Could not find class ' android.support.v4.view.ViewPager ' problem handling

Could not find class ' Android.support.v4.view.ViewPager ', referenced from method***

And I have introduced Viewpager package, compile is not error, but run times Viewpager does not exist.

Workaround:

1. Since the jar package is not imported in the project, we will import it manually:

Right-click the project selection Bulid path->add libraries->user library->user libraries->new (pick a name, like Viewpager)->add Jars ( Add the required jar packages to the Viewpager):

2. In the properties settings, right-click on the project->properties->java Build Path->order and Export will just new "Viewpager" tick OK. ：

Could not find class ' android.support.v4.view.ViewPager ' problem handling