macos - 如何检测 NSTextField 何时获得焦点或者其内容是否被选中 cocoa

Question

我在 NSTableCellView 中有一个 NSTextField，我想要一个事件，当我的 NSTextField 获得焦点以禁用多个按钮时通知我，我找到了这个方法:

-(void)controlTextDidBeginEditing:(NSNotification *)obj{
    NSTextField *textField  = (NSTextField *)[obj object];

    if (textField != _nombreDelPaqueteTextField) {
        [_nuevaCuentaActivoButton   setEnabled:FALSE];
        [_nuevaCuentaPasivoButton   setEnabled:FALSE];
        [_nuevaCuentaIngresosButton setEnabled:FALSE];
        [_nuevaCuentaEgresosButton  setEnabled:FALSE];
    }
}

但它会在我的文本字段开始编辑时触发，如下所示，我希望当我将焦点放在文本字段上时禁用按钮，而不是当我已经开始输入时

<小时/>

编辑:将根据Joshua Nozzi收到的帮助放置我的代码，但它仍然不起作用

MyNSTextField.h

#import <Cocoa/Cocoa.h>
@class MyNSTextField;

@protocol MyNSTextFieldDelegate

@optional -(BOOL)textFieldDidResignFirstResponder:(NSTextField *)sender;
@optional -(BOOL)textFieldDidBecomeFirstResponder:(NSTextField *)sender;

@end

@interface MyNSTextField : NSTextField

@property (strong, nonatomic)           id <MyNSTextFieldDelegate> cellView;

@end

MyNSTextField.m

#import "MyNSTextField.h"

@implementation MyNSTextField

- (BOOL)becomeFirstResponder
{
    BOOL status = [super becomeFirstResponder];
    if (status)

        [self.cellView textFieldDidBecomeFirstResponder:self];
    return status;
}

- (BOOL)resignFirstResponder
{
    BOOL status = [super resignFirstResponder];
    if (status)
        [self.cellView textFieldDidResignFirstResponder:self];
    return status;
}

@end

在我的 View Controller EdicionDeCuentasWC.m

#import "MyNSTextField.h"


@interface EdicionDeCuentasWC ()<NSTableViewDataSource, NSTableViewDelegate, NSControlTextEditingDelegate, NSPopoverDelegate, MyNSTextFieldDelegate>
@end


@implementation EdicionDeCuentasWC
#pragma mark MyNSTextFieldDelegate
-(BOOL)textFieldDidBecomeFirstResponder:(NSTextField *)sender{
    NSLog(@"textFieldDidBecomeFirstResponder");
    return TRUE;
}

-(BOOL)textFieldDidResignFirstResponder:(NSTextField *)sender{
    NSLog(@"textFieldDidResignFirstResponder");
    return TRUE;
}
#pragma mark --
@end

重要的是在可视化编辑器中，已经将我的所有 NSTextField 更改为 MyNSTextField 类并将委托(delegate)设置为我的文件所有者 (EdicionDeCuentasWC)

Answer 1

我想我已经成功了。我试图子类化 NSTextFiled 来覆盖 becomeFirstResponder() 和 resignFirstResponder()，但是一旦我单击它，becomeFirstResponder() 被调用，然后 resignFirstResponder() 被调用。啊？但搜索字段看起来仍在编辑中，焦点仍在其上。

我发现，当您单击搜索字段时，搜索字段会成为第一响应者一次，但是 NSText 会在稍后的某个地方准备好，并且焦点将移动到 NSText .

我发现当 NSText 准备好时，它被设置为 self.currentEditor() 。问题是，当调用 becomeFirstResponder() 时，self.currentEditor() 尚未设置。所以 becomeFirstResponder() 不是检测焦点的方法。

另一方面，当焦点移动到 NSText 时，文本字段的 resignFirstResponder() 被调用，你知道吗？ self.currentEditor() 已设置。因此，现在是告诉它的委托(delegate)该文本字段获得焦点的时刻。

接下来，如何检测搜索字段何时失去焦点。再说一遍，这是关于 NSText 的。然后，您需要监听 NSText 委托(delegate)的方法，例如 textDidEndEditing()，并确保让其父类(super class)处理该方法，并查看是否 self.currentEditor( ) 无效。如果是这种情况，NSText 会失去焦点并告知文本字段的委托(delegate)。

我提供了一段代码，实际上是NSSearchField子类来做同样的事情。同样的原理也适用于 NSTextField。

protocol ZSearchFieldDelegate: NSTextFieldDelegate {
    func searchFieldDidBecomeFirstResponder(textField: ZSearchField)
    func searchFieldDidResignFirstResponder(textField: ZSearchField)
}


class ZSearchField: NSSearchField, NSTextDelegate {

    var expectingCurrentEditor: Bool = false

    // When you clicked on serach field, it will get becomeFirstResponder(),
    // and preparing NSText and focus will be taken by the NSText.
    // Problem is that self.currentEditor() hasn't been ready yet here.
    // So we have to wait resignFirstResponder() to get call and make sure
    // self.currentEditor() is ready.

    override func becomeFirstResponder() -> Bool {
        let status = super.becomeFirstResponder()
        if let _ = self.delegate as? ZSearchFieldDelegate where status == true {
            expectingCurrentEditor = true
        }
        return status
    }

    // It is pretty strange to detect search field get focused in resignFirstResponder()
    // method.  But otherwise, it is hard to tell if self.currentEditor() is available.
    // Once self.currentEditor() is there, that means the focus is moved from 
    // serach feild to NSText. So, tell it's delegate that the search field got focused.

    override func resignFirstResponder() -> Bool {
        let status = super.resignFirstResponder()
        if let delegate = self.delegate as? ZSearchFieldDelegate where status == true {
            if let _ = self.currentEditor() where expectingCurrentEditor {
                delegate.searchFieldDidBecomeFirstResponder(self)
                // currentEditor.delegate = self
            }
        }
        self.expectingCurrentEditor = false
        return status
    }

    // This method detect whether NSText lost it's focus or not.  Make sure
    // self.currentEditor() is nil, then that means the search field lost its focus,
    // and tell it's delegate that the search field lost its focus.

    override func textDidEndEditing(notification: NSNotification) {
        super.textDidEndEditing(notification)

        if let delegate = self.delegate as? ZSearchFieldDelegate {
            if self.currentEditor() == nil {
                delegate.searchFieldDidResignFirstResponder(self)
            }
        }
    }

}

您需要将 NSSerachField 更改为 ZSearchField，并且您的客户端类必须符合 ZSearchFieldDelegate 而不是 NSTextFieldDelegate 。这是一个例子。当用户单击搜索字段时，它会扩展其宽度，而当您单击其他位置时，通过更改 Interface Builder 设置的 NSLayoutConstraint 值，搜索字段会失去焦点并缩小其宽度。

class MyViewController: NSViewController, ZSearchFieldDelegate {

    // [snip]

    @IBOutlet weak var searchFieldWidthConstraint: NSLayoutConstraint!

    func searchFieldDidBecomeFirstResponder(textField: ZSearchField) {
        self.searchFieldWidthConstraint.constant = 300
        self.view.layoutSubtreeIfNeeded()
    }

    func searchFieldDidResignFirstResponder(textField: ZSearchField) {
        self.searchFieldWidthConstraint.constant = 100
        self.view.layoutSubtreeIfNeeded()
    }

}

这可能取决于操作系统的行为，我在 El Capitan 10.11.4 上尝试过，并且成功了。

代码也可以从 Gist 复制。 https://gist.github.com/codelynx/aa7a41f5fd8069a3cfa2