Can I close external applications with Robotium?

I have my开发者_JS百科 Android app and there are 4 buttons. Each of them calls an application like Facebook app, Twitter app, default email app and phone call.

When I am testing these buttons with Robotium, is it possible to close the external applications from within the test script?

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There is no native way for robotium to be able to interact with multiple applications at once. See this question. It seems like they had a similar issue.