UISearchBar未显示范围栏

Question

我使用以下代码显示带有范围栏的UISearchBar。

UISearchBar *searchBar = [[UISearchBar alloc]initWithFrame:CGRectMake(0, 0, 320, 45)];
searchBar.barStyle = UIBarStyleDefault;
searchBar.showsCancelButton = NO;
searchBar.autocorrectionType = UITextAutocorrectionTypeNo;
searchBar.autocapitalizationType = UITextAutocapitalizationTypeNone;

searchBar.scopeButtonTitles = [NSArray arrayWithObjects:@"One", @"Two", nil];
searchBar.showsScopeBar = YES;

self.tableView.tableHeaderView = searchBar;

[searchBar release];

但是，范围栏永远不会显示。为什么没有显示，我该如何解决？

Answer 1

<{1>}中的

，高度只是搜索栏的高度，不包括范围栏。尝试用以下内容替换：

initWithFrame:CGRectMake(0, 0, 320, 45)

Answer 2

(void) searchDisplayControllerWillBeginSearch:(UISearchDisplayController *)
 controller{  
    _searchBar.showsScopeBar = YES;
    [_searchBar sizeToFit];
}

Answer 3

如果您没有UISearchDisplayController，可以尝试使用 UISearchBarDelegate 回调：

- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar
{
  self.searchBar.showsScopeBar = YES;
  [self.searchBar sizeToFit];
  return YES;
}

- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar{
  self.searchBar.showsScopeBar = NO;
  [self.searchBar sizeToFit];
}