NSResponder resignFirstResponder对错误的对象触发

Question

我有一个带有一些NSTextFields的Mac应用程序(SDK10.10)：

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由于我需要在文本字段获得和放弃焦点时得到通知，所以我将NSTextField子类：

@interface MyTextField : NSTextField
@end

@implementation MyTextField

- (BOOL)becomeFirstResponder
{
    BOOL didBecomeFirstResponder = [super becomeFirstResponder];
    NSLog(@"%@ didBecomeFirstResponder = %@", [self accessibilityLabel], didBecomeFirstResponder?@"YES":@"NO");
    return didBecomeFirstResponder;
}

- (BOOL)resignFirstResponder
{
    BOOL didResignFirstResponder = [super resignFirstResponder];
    NSLog(@"%@ didResignFirstResponder = %@", [self accessibilityLabel], didResignFirstResponder?@"YES":@"NO");
    return didResignFirstResponder;
}

@end

当运行这段代码并在三个文本字段之间加标签时，我在控制台中得到了这个输出：

firstField didResignFirstResponder = YES
firstField didBecomeFirstResponder = YES
secondField didResignFirstResponder = YES
secondField didBecomeFirstResponder = YES
thirdField didResignFirstResponder = YES
thirdField didBecomeFirstResponder = YES
firstField didResignFirstResponder = YES
firstField didBecomeFirstResponder = YES
secondField didResignFirstResponder = YES
secondField didBecomeFirstResponder = YES

每次我按TAB键(或单击其中一个不活动的文本字段)，应用程序就会输出。

<new first responder> didResignFirstResponder = YES
<new first responder> didBecomeFirstResponder = YES

不是吗？

<old first responder> didResignFirstResponder = YES
<new first responder> didBecomeFirstResponder = YES

?？?

我这里有什么严重的问题吗？

- (BOOL)resignFirstResponder的文档显示

通知接收方，它已被要求放弃其窗口中的第一个响应者的身份。

那么，为什么resignFirstResponder会调用新的第一响应者而不是旧的响应者呢？

Answer 1

我也遇到了同样的问题，无法找到解决方案，因此我最终解决了这个问题，并为了同样的目的使用了textDidEndEditing()方法。Swift代码：

MyTextField子类NSTextField，并向其添加myDelegate属性，以便在文本字段失去焦点后处理逻辑。

class MyTextField : NSTextField
{

/// Custom delegate with other methods than NSTextFieldDelegate.
var myDelegate: MyTextFieldDelegate? = nil;

override func becomeFirstResponder() -> Bool {
    let became = super.becomeFirstResponder();
    if (became) {
        self.myDelegate?.myTextFieldDidBecomeFirstResponder(self);
    }
    return became;
}

override func resignFirstResponder() -> Bool {
    let resigned = super.resignFirstResponder();
    if (resigned) {
        self.myDelegate?.myTextFieldDidResignFirstResponder(self);
    }
    return resigned;
}

override func textDidEndEditing(obj: NSNotification) {
    super.textDidEndEditing(obj);
    self.myDelegate?.myTextFieldDidResignFirstResponder(self);
}

}

议定书本身：

protocol MyTextFieldDelegate
{

    func myTextFieldDidBecomeFirstResponder(textField: MyTextField);

    func myTextFieldDidResignFirstResponder(textField: MyTextField);
}

显然，您可以直接实现丢失/获取的焦点逻辑，而不是使用和调用委托(例如，绘制不同的边界，等等)。

线索是textDidEndEditing()方法，当我在另一个字段中单击、按enter或退出时，它似乎工作得很好。