如何Nav点击后退按钮时刷新之前一个UITableView

  

Just so we're clear: view A is the starting point. User taps something and you slide right to view B. User taps the back button and you're going from B back to A and you want to do something as a result of the 'back' action.

There are three ways to do it (and on neither do you have to go near the navigationController -- these apply to the underlying viewControllers themselves):

• As dmercredi suggests override viewWillAppear on view controller A so when you're heading back to it, it refreshes itself. Problem is that viewWillAppear is also called when A is called the very first time. So you'll have to set some sort of flag to distinguish between the firstviewWillAppear and any subsequent ones when returning from B.

• Override viewWillDisappear on view controller B and do your refreshing there. This will only get called when B is about to go away. If there's something on B that goes one level deeper or brings up a modal dialog on top, viewWillDisappear is going to get called so again you'll have to distinguish between the coming and the going.

• 
  
  Decouple the various views and use the delegate pattern. View controller A sets itself as a delegate of B and when B updates something it invokes the delegate method, so A is notified of the change and can update whatever it needs to. You can invoke the delegate method any time the user makes a change inside B or override viewWillDisappear and just do it one time on the way out. 
  
  
  老外总结的三种方法，还有个方法，也是个老外说得，把View A的指针直接传给B，然后让B直接去调用这个指针做更新，不太确定是否可行，感觉理论上没什么问题。实践中是用方法三完成的，View controller A将其自身设成B的delegate,当B需要更新A的时候，就调用A的delegate方法，同时在A的delegate方法中视图更新动作[tableView reloadData]. 其中tableView是一个IBOutlet，指向View Controller A中的TableView.网上好多例子都是用的viewWillAppear，但是有人说会有明显刷新的痕迹，就是屏幕会闪一下。目前先用方法三对付，如果后期发现更好的方法再改改。