By default, only UIViewController's prepareForSegue: can notify us the segue will perform. But We can't know when the segue performed. At the same time, you can't stop a segue to be preformed on iOS5.

So we provide RFSegueSourceDelegate and RFSegueDestinationDelegate. You can decide wether should perform a segue or not. Get notify when a segue will perform and did perform.

Tips: After iOS6, you can use shouldPerformSegueWithIdentifier:sender: instead of RFSegueShouldPerform:.

Using segue we can transit between view controllers conveniently from the outside in. But how to return? Generally we must write some code. We had subclassed UIButton and UIBarButtonItem to make this as convenient as segue. For an UIButton, you just change it’c class, no more operate! You need drag masterViewController IBOutlet to current view controller if there are UIBarButtonItem. IBAction or addTarget no longer needed.

Also, RFSegueReturnDelegate provide necessary notifications and control.