UIBarButtonItem.appearance(whenContainedInInstancesOf: [UISearchBar.self]).title="取消"
searchC = UISearchController.init(searchResultsController: nil)
searchC.searchResultsUpdater = self
searchC.searchBar.placeholder = "搜索地址".add()
searchC.obscuresBackgroundDuringPresentation = false
navigationItem.hidesSearchBarWhenScrolling = false
navigationItem.searchController = searchC
searchC.searchBar.showsCancelButton = true
UIBarButtonItem.appearance(whenContainedInInstancesOf: [UISearchBar.self]).title="取消"
searchC.searchBar.returnKeyType = .search