在视图加载时自动将焦点设置为UITableView的第一个单元格

Question

我一直在尝试创建一个应用程序,当视图加载时,焦点自动转到UITableview的第一个单元格.

我尝试过使用UIFocusGuide,然后在prefferedFocusView()方法中返回tableView,但是没有用.

然后我写了这段代码

 var viewToFocus: UIView? = nil {
    didSet {
        if viewToFocus != nil {
            print("called1 ")
            self.setNeedsFocusUpdate();
            self.updateFocusIfNeeded();
        }
    }
}

override weak var preferredFocusedView: UIView? {
    if viewToFocus != nil {
        print("called2 ")

        return viewToFocus;
    } else {
        return super.preferredFocusedView;
    }
}

在视图中确实加载

        self.viewToFocus = myTableView

但这并没有奏效.

Answer 1

我能够通过设置来得到这个tableView.remembersLastFocusedIndexPath = true的viewDidLoad话,我实施了首选焦点委托方法:

func indexPathForPreferredFocusedView(in tableView: UITableView) -> IndexPath? {
   return NSIndexPath(forItem: 0, inSection: 0)
}

当remembersLastFocusedIndexPath-If YES, when focusing on a table view the last focused index path is focused automatically. If the table view has never been focused, then the preferred focused index path is used.