swift中 UISearchBar没有文本内容，也可以点击键盘上的搜索？但是现在就是没有文本内容就是点不了搜索按钮

在 Swift 中，可以通过实现 UISearchBarDelegate 的 searchBarSearchButtonClicked 方法来响应搜索按钮的点击事件。如果搜索栏没有文本内容，搜索按钮默认是不可点击的。如果你想在搜索栏没有文本内容时也能点击搜索按钮，可以手动设置搜索按钮的 isEnabled 属性为 true。具体实现如下：

class ViewController: UIViewController, UISearchBarDelegate {
    @IBOutlet weak var searchBar: UISearchBar!

    override func viewDidLoad() {
        super.viewDidLoad()
        searchBar.delegate = self
    }

    func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
        // 处理搜索逻辑
    }

    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        if searchText.isEmpty {
            searchBar.showsCancelButton = false
            searchBar.searchTextField.rightView?.isHidden = false
            searchBar.searchTextField.rightViewMode = .always
            searchBar.searchTextField.clearButtonMode = .whileEditing
            searchBar.searchTextField.enablesReturnKeyAutomatically = false
            searchBar.searchTextField.returnKeyType = .default
            searchBar.searchTextField.reloadInputViews()
            searchBar.setShowsCancelButton(false, animated: true)
            searchBar.searchTextField.resignFirstResponder()
            searchBar.searchTextField.endEditing(true)
            searchBar.searchTextField.isUserInteractionEnabled = true
            searchBar.searchTextField.isEnabled = true
            searchBar.searchTextField.reloadInputViews()
            searchBar.searchTextField.returnKeyType = .search
            searchBar.searchTextField.becomeFirstResponder()
        } else {
            searchBar.searchTextField.rightView?.isHidden = true
            searchBar.searchTextField.rightViewMode = .always
            searchBar.searchTextField.clearButtonMode = .whileEditing
            searchBar.searchTextField.enablesReturnKeyAutomatically = true
            searchBar.searchTextField.returnKeyType = .search
            searchBar.searchTextField.reloadInputViews()
            searchBar.setShowsCancelButton(true, animated: true)
            searchBar.searchTextField.becomeFirstResponder()
        }
    }
}

在实现中，我们在 searchBar(_:textDidChange:) 方法中判断搜索栏的文本内容是否为空，如果为空，手动设置搜索按钮的 isEnabled 属性为 true，这样就能在没有文本内容时点击搜索按钮了。