why viewWillDisAppear is not being called in detail view?

I think lot of people are facing the same problem .

In detail view i.e tapping on cell in main view takes you to the detail when in navigation bar I tapp the back button the viewWillDisAppear is not being called as I want to remove some keyboard hide and show observers .

So what is the way that at the time 开发者_StackOverflowof view disappearing I assure the viewWillDisAppear will be executed.

In the case you describe, it certainly sounds like it should be called. My first guess would be that you're not overriding the right function. Make sure the method signature matches exactly (spaces can be ignored, capitalization must match):

- (void) viewWillDisappear:(BOOL)animated {
  //...