问题
I have updated ios 9 in my phone. After that I have installed my app in my phone. I have faced the problem for doesn't show the back button in navigation bar. but show the back button in navigation bar in ios 8.
what is the problem for that? How can I resolve that problem?
来源：https://stackoverflow.com/questions/32687549/doesnt-show-the-back-button-in-navigation-bar-in-ios-9