objective-c - 覆盖 NSTextfield 中的 keydownevent

Question

我做了一个 nstextfield 的子类，我重写了 keydown 事件，但我的代码不起作用，然后我重写了 de keyup 事件，代码完美运行。我的按键代码(不起作用):

-(void)keyDown:(NSEvent *)event {
    NSLog(@"Key released: %hi", [event keyCode]);

    if ([event keyCode]==125){

        [[self window] selectKeyViewFollowingView:self];
    }
    if ([event keyCode]==126){

        [[self window] selectKeyViewPrecedingView:self];
    }

}

我的 keyup 代码(有效):

-(void)keyUp:(NSEvent*)event
{if ([event keyCode]==125){

        [[self window] selectKeyViewFollowingView:self];
    }
    if ([event keyCode]==126){

        [[self window] selectKeyViewPrecedingView:self];
    }

    if ([event keyCode]==36){

        [[self window] selectKeyViewFollowingView:self];
    }

    }

我看不出我的 keydown 代码哪里有问题。任何建议都将被接受

编辑:我读到你必须继承 NSTextView 而不是 NSTextField。

Answer 1

您可以使用 NSTextFieldDelegate 方法在不进行子类化的情况下完成此操作:

正如@Darren Inksetter 所说，您可以使用 control:textView:doCommandBySelector:

首先，在您的界面标签中声明 NSTextFieldDelegate。然后实现方法:

- (BOOL)control:(NSControl *)control textView:(NSTextView *)textView doCommandBySelector:(SEL)commandSelector
{
    if( commandSelector == @selector(moveUp:) ){
        // Do yourthing here, like selectKeyViewFollowingView
        return YES;    // Return YES means don't pass it along responders chain. Return NO if you still want system's action on this key.
    }
    if( commandSelector == @selector(moveDown:) ){
        // Do the same with the keys you want to track
        return YES;
    }
    return NO;
}