從A界面跳轉(zhuǎn)到B界面璃诀，本來通過調(diào)用[self.navigationController pushViewController:vc animated:YES]這個(gè)方法弧可，即可在B界面自動(dòng)生成導(dǎo)航，但是卻一直不顯示劣欢，仔細(xì)檢查代碼棕诵，發(fā)現(xiàn)在B界面添加了隱藏了代碼：
-(void)viewWillAppear:(BOOL)animated{
? ?[self.navigationController.navigationBar setHidden:YES];
}
-(void)viewWillDisappear:(BOOL)animated{? ?
?[self.navigationController.navigationBar setHidden:NO];
}
