导航栏的高度在所有苹果机型是都是44

CGRect rectStatus = [[UIApplication sharedApplication] statusBarFrame];

NSLog(@"status width - %f", rectStatus.size.width); // 宽度

NSLog(@"status height - %f", rectStatus.size.height);  // 高度

// 导航栏（navigationbar）

CGRect rectNav = self.navigationController.navigationBar.frame;

NSLog(@"nav width - %f", rectNav.size.width); // 宽度

NSLog(@"nav height - %f", rectNav.size.height);  // 高度

2016-12-16 15:59:25.215 AisouDemo[17748:284020] status width - 320.000000

2016-12-16 15:59:25.216 AisouDemo[17748:284020] status height - 20.000000

2016-12-16 15:59:25.216 AisouDemo[17748:284020] nav width - 320.000000

2016-12-16 15:59:25.216 AisouDemo[17748:284020] nav height - 44.000000