NSTextField输入键检测或firstResponder检测

我有两个NSTextFields: textFieldUserID and textFieldPassword.

For textFieldPassword，我有一个代表如下：

- (void)controlTextDidEndEditing:(NSNotification *)aNotification

该代表在以下情况下被调用textFieldPassword获得焦点后我按下了 Enter 键。这正是我想要的。

我的问题是controlTextDidEndEditing也被调用时textFieldPassword有焦点，我将焦点移至textFieldUserID（通过鼠标或 Tab 键）。这不是我想要的。

我尝试使用controlTextDidChange通知（每次按键都会调用一次），但我无法弄清楚如何检测回车键（[textFieldPassword stringValue]不包括回车键）。有人可以帮我解决这个问题吗？

我也尝试检测是否textFieldUserID was a firstResponder，但它对我不起作用。这是我尝试过的代码：

if ( [[[self window] firstResponder] isKindOfClass:[NSTextView class]] &&
    [[self window] fieldEditor:NO forObject:nil] != nil ) {
    NSTextField *field = [[[self window] firstResponder] delegate];
    if (field == textFieldUserID) {
        // do something based upon first-responder status
        NSLog(@"is true");
    }
}

我确实需要一些帮助！

If I understood you correctly, you could set an action for the password text field and tell the field to send its action only when the user types Return. Firstly, declare and implement an action in the class responsible for the behaviour when the user types Return on the password field. For example:

@interface SomeClass …
- (IBAction)returnOnPasswordField:(id)sender;
@end

@implementation SomeClass
- (IBAction)returnOnPasswordField:(id)sender {
    // do something
}
@end

Making the text field send its action on Return only, and linking the action to a given IBAction and target, can be done either in Interface Builder or programatically.

在 Interface Builder 中，使用 Attributes Inspector，选择操作：仅在输入时发送，然后将文本字段操作链接到IBAction在实现它的对象中，可能是文件所有者或第一响应者。

如果您更愿意以编程方式执行此操作，那么：

// Make the text field send its action only when Return is pressed
[passwordTextFieldCell setSendsActionOnEndEditing:NO];

// The action selector according to the action defined in SomeClass
[passwordTextFieldCell setAction:@selector(returnOnPasswordField:)];

// someObject is the object that implements the action
[passwordTextFieldCell setTarget:someObject];