UISearchBar 取消按钮

Question

在 iOS 5 上使用带有 showCancelButton=YES 的 UISearchBar。希望在键盘下拉时取消按钮保持启用状态。使用以下代码似乎不起作用:

for (id subView in self.searchControl.subviews) {
    if ([subView isKindOfClass:[UIButton class]]) {
        UIButton *cancelButton = (UIButton *)subView;
        [cancelButton setEnabled:YES];
        break;
    }         
}

subView 实际上是一个 UINavigationButton，它似乎不是 UIButton 的子类。我在这里想念什么？？？？？？在 Apple 文档中也找不到有关 UINavigationButton 类的任何信息。

Answer 1

设置您的搜索栏委托(delegate)，然后放置此代码。

- (void) searchBarSearchButtonClicked:(UISearchBar*) theSearchBar
  {
     [theSearchBar resignFirstResponder];
     [theSearchBar setShowsCancelButton:NO animated:YES];
  }
 - (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar
  {
     [searchBar setShowsCancelButton:YES animated:YES];
  }
  - (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar
  {
     [searchBar resignFirstResponder];
     [searchBar setShowsCancelButton:NO animated:YES];
  }

swift 3.0

func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
     searchBar.resignFirstResponder()
     searchBar.setShowsCancelButton(false, animated: true)
}
func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {
     searchBar.setShowsCancelButton(true, animated: true)
}
func searchBarCancelButtonClicked(_ searchBar: UISearchBar) {
     searchBar.resignFirstResponder()
     searchBar.setShowsCancelButton(false, animated: true)
}