How to get the view controller currently being executed in the AppDeleage

Projects have multiple view controllers

In one view controller to add functionality to share microblogging, microblogging and sharing functions performed AppDelegate method to invoke when the current view controller does not call the object's methods of micro-Bo, I do not have a personal analysis of the problem in Gets the view controller is currently being executed.

Who knows next Thank you for reminding me! ! !
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Nobody knows ah seems CSDN iphone development personnel or less ah! !
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Send a message to solve this problem
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What is the view controller currently being executed?
Refers to the currently displayed view controller belongs?

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Unknown said, never in the agency have been feeling this child fall ...... notice easy to use than the agent
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Paste the code look