UISearchBar 搜寻框

UISearchBar 搜索框
   UISearchBar *searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, 320, 50)];
        searchBar.placeholder=@"关键字";
        searchBar.showsCancelButton = YES;
        searchBar.barStyle = UIBarStyleBlack;
//        searchBar.keyboardType=UIKeyboardTypeDefault;
//        [searchBar resignFirstResponder]; //可以清空搜索框
        searchBar.delegate = self;
        [self addSubview:searchBar];