键盘没有显示在ios8上

Question

如下进行。

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
[view addSubView:nameTextField];
[nameTextField becomeFirstResponder];`

但键盘没有出现。

按Home键后，如果返回应用程序，则会出现键盘。

我不知道原因。

Answer 1

使用以下代码检查：

override func viewDidLoad() {
        super.viewDidLoad()

        NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillAppear:", name: UIKeyboardWillShowNotification, object: nil)
        NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillDisappear:", name: UIKeyboardWillHideNotification, object: nil)
    }

    func keyboardWillAppear(notification: NSNotification){
        // Do something here
    }

    func keyboardWillDisappear(notification: NSNotification){
        // Do something here
    }

并且不要忘记在viewwillappear中删除观察者，如下所示：

override func viewWillDisappear(animated: Bool) {
    super.viewWillDisappear(animated)
    NSNotificationCenter.defaultCenter().removeObserver(self)
}