NSViewController中的firstResponder [英] firstResponder in NSViewController

问题描述

我有两节课。 NSViewController是NSViewController的子类，而ViewController是Auf管理ViewController的子类。在Viewcontroller中，我有一个NSTextField，我想成为它的firstResponder，但我没有做到这一点。

I've got two classes. ManagingViewController, a subclass of NSViewController, and ViewController, a subclass auf ManagingViewController. In Viewcontroller I've got a NSTextField which I want to become the firstResponder, but I didn't manage that.

所以它几乎与第29章中的相同Hillegass的书《适用于Mac OS X的可可编程》（下载该书中的示例

So it is nearly the same like the Chapter 29 in Hillegass' book Cocoa Programming for Mac OS X (Download of the book's examples) except of an NSTextField which is set to firstResponder.

有人可以指出我正确的方法吗？

Can anybody point me to the correct way?

推荐答案

您需要使用-[NSWindow makeFirstResponder：] 将文本字段设置为第一响应者。

You need to set the text field as the first responder by using -[NSWindow makeFirstResponder:].

由于这是 NSWindow 方法，因此只有在将相应的视图添加到窗口之后（即在已将视图添加为窗口视图层次结构内的子视图。在这本书的示例中，将视图设置为窗口内框的内容视图时，就会发生这种情况。例如：

Since this is an NSWindow method, it only makes sense after you’ve added the corresponding view to the window, i.e., after you’ve added the view as a subview inside the window view hierarchy. In the book’s example, this happens when you set the view as the content view of the box inside the window. For example:

- (void)displayViewController:(ManagingViewController *vc) {
    // Try to end editing
    NSWindow *w = [box window];
    …

    // Put the view in the box
    NSView *v = [vc view];
    [box setContentView:v];

    // Set the first responder
    if ([vc class] == [ViewController class]) {
        [w makeFirstResponder:[(ViewController *)vc myTextField]];
    }
}

这是假定 ViewController 公开了称为 -myTextField 的吸气方法。

This assumes ViewController exposes a getter method called -myTextField.

您可以通过以下方法使它更通用视图控制器公开一种方法，该方法返回视图控制器建议作为第一响应者的对象。像这样的东西：

You can make this more generic by having your view controllers expose a method that returns the object that the view controller recommends as the first responder. Something like:

@interface ManagingViewController : NSViewController
…
- (NSResponder *)recommendedFirstResponder;
@end

@implementation ManagingViewController
…
- (NSResponder *)recommendedFirstResponder { return nil; }
@end

然后，在 ManagingViewController的具体子类中，具有 -recommendedFirstResponder 返回应该是窗口的第一响应者的对象：

And, in your concrete subclasses of ManagingViewController, have -recommendedFirstResponder return the object that should be the window’s first responder:

@implementation ViewController
…
- (NSResponder *)recommendedFirstResponder { return myTextField; }
@end

完成此操作后，您可以更改 -displayViewController：到类似这样的东西：

Having done that, you can change your -displayViewController: to something like:

- (void)displayViewController:(ManagingViewController *vc) {
    // Try to end editing
    NSWindow *w = [box window];
    …

    // Put the view in the box
    NSView *v = [vc view];
    [box setContentView:v];

    // Set the first responder
    NSResponder *recommendedResponder = [vc recommendedFirstResponder];
    if (recommendedResponder) [w makeFirstResponder:recommendedResponder];
}

这篇关于NSViewController中的firstResponder的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！