在OSX中，如何判断哪个键盘产生了NSEvent？

Question

我一直在尝试确定（从事件处理程序中）哪个键盘触发了事件。我一直在使用这两个帖子：

在第二篇文章中，作者使用 Carbon 技术成功地分离出了他的键盘，但是使用 Cocoa 尝试同样的技巧失败了。

在我自己的系统上都失败了，可能是因为我的无线键盘也是苹果制造的，所以可能会报告与内置键盘相同的标识符。

在第一篇文章中，有人提出了一种在较低级别（可以区分键盘）监视键盘事件并将此数据存储在队列中，并让事件处理程序检索信息的解决方案。

这看起来有点毛茸茸，所以我只是在这里查看是否有人找到了更好的东西。

这是我的代码，它演示了在事件处理程序中区分键盘的失败：

// compile and run from the commandline with:
//    clang -fobjc-arc -framework Cocoa -framework Carbon  ./tap_k.m  -o tap_k
//    sudo ./tap_k

#import <Foundation/Foundation.h>
#import <AppKit/NSEvent.h>
//#import <CarbonEventsCore.h>
#include <Carbon/Carbon.h>


typedef CFMachPortRef EventTap;

// - - - - - - - - - - - - - - - - - - - - -

@interface KeyChanger : NSObject
{
@private
    EventTap            _eventTap;
    CFRunLoopSourceRef  _runLoopSource;
    CGEventRef          _lastEvent;
}
@end

// - - - - - - - - - - - - - - - - - - - - -

CGEventRef _tapCallback(
                        CGEventTapProxy proxy,
                        CGEventType     type,
                        CGEventRef      event,
                        KeyChanger*     listener
                        );

// - - - - - - - - - - - - - - - - - - - - -

@implementation KeyChanger

- (BOOL)tapEvents
{
    if (!_eventTap) {
        NSLog(@"Initializing an event tap.");

        // kCGHeadInsertEventTap -- new event tap should be inserted before any pre-existing event taps at the same location,
        _eventTap = CGEventTapCreate( kCGHIDEventTap, // kCGSessionEventTap,
                                      kCGHeadInsertEventTap,
                                      kCGEventTapOptionDefault,
                                           CGEventMaskBit( kCGEventKeyDown )
                                         | CGEventMaskBit( kCGEventFlagsChanged )
                                         | CGEventMaskBit( NSSystemDefined )
                                         ,
                                      (CGEventTapCallBack)_tapCallback,
                                      (__bridge void *)(self));
        if (!_eventTap) {
            NSLog(@"unable to create event tap. must run as root or "
                    "add privlidges for assistive devices to this app.");
            return NO;
        }
    }
    CGEventTapEnable(_eventTap, TRUE);

    return [self isTapActive];
}

- (BOOL)isTapActive
{
    return CGEventTapIsEnabled(_eventTap);
}

- (void)listen
{
    if( ! _runLoopSource ) {
        if( _eventTap ) { // dont use [self tapActive]
            NSLog(@"Registering event tap as run loop source.");
            _runLoopSource = CFMachPortCreateRunLoopSource( kCFAllocatorDefault, _eventTap, 0 );

            // Add to the current run loop.
            CFRunLoopAddSource( CFRunLoopGetCurrent(), _runLoopSource, kCFRunLoopCommonModes );

            CFRunLoopRun();
        }else{
            NSLog(@"No Event tap in place! You will need to call listen after tapEvents to get events.");
        }
    }
}

- (CGEventRef)processEvent:(CGEventRef)cgEvent
{
    NSEvent* event = [NSEvent eventWithCGEvent:cgEvent];


    //NSEventType type = [event type];

    EventRef ce = (EventRef)[event eventRef];

    if(ce)
    {
        unsigned kbt;
        GetEventParameter(
                            ce,
                            kEventParamKeyboardType,
                            typeUInt32, NULL,
                            sizeof kbt, NULL,
                            & kbt
                            );

        NSLog(@"CARBON Keyboard type: %d",kbt);
    }

    CGEventSourceRef evSrc = CGEventCreateSourceFromEvent( cgEvent );

    if(evSrc)
    {
        unsigned kbt = (NSUInteger) CGEventSourceGetKeyboardType( evSrc );
        CFRelease(evSrc);
        NSLog(@"COCOA: %d",kbt);
    }

    //[super sendEvent:anEvent];
    //}


    NSUInteger modifiers = [event modifierFlags] &
        (NSCommandKeyMask | NSAlternateKeyMask | NSShiftKeyMask | NSControlKeyMask);

    enum {
       kVK_ANSI_3 = 0x14,
    };


    switch( event.type ) {
        case NSFlagsChanged:
            NSLog(@"NSFlagsChanged: %d", event.keyCode);
            break;

        case NSSystemDefined:
            NSLog(@"NSSystemDefined: %lx", event.data1);
            return NULL;

        case kCGEventKeyDown:
            NSLog(@"KeyDown: %d", event.keyCode);
            break;

        default:
            NSLog(@"WTF");
    }


    // TODO: add other cases and do proper handling of case
    if (
        //[event.characters caseInsensitiveCompare:@"3"] == NSOrderedSame
        event.keyCode == kVK_ANSI_3
        && modifiers == NSShiftKeyMask
        ) 
    {
        NSLog(@"Got SHIFT+3");

        event = [NSEvent keyEventWithType: event.type
                                 location: NSZeroPoint
                            modifierFlags: event.modifierFlags & ! NSShiftKeyMask
                                timestamp: event.timestamp
                             windowNumber: event.windowNumber
                                  context: event.context
                               characters: @"#"
              charactersIgnoringModifiers: @"#"
                                isARepeat: event.isARepeat
                                  keyCode: event.keyCode];
    }
    _lastEvent = [event CGEvent];
    CFRetain(_lastEvent); // must retain the event. will be released by the system
    return _lastEvent;
}

- (void)dealloc
{
    if( _runLoopSource ) {
        CFRunLoopRemoveSource( CFRunLoopGetCurrent(), _runLoopSource, kCFRunLoopCommonModes );
        CFRelease( _runLoopSource );
    }
    if( _eventTap ) {
        //kill the event tap
        CGEventTapEnable( _eventTap, FALSE );
        CFRelease( _eventTap );
    }
}

@end

// - - - - - - - - - - - - - - - - - - - - -

CGEventRef _tapCallback(
                        CGEventTapProxy proxy,
                        CGEventType     type,
                        CGEventRef      event,
                        KeyChanger*     listener
                        )
{
    //Do not make the NSEvent here.
    //NSEvent will throw an exception if we try to make an event from the tap timout type
    @autoreleasepool {
        if( type == kCGEventTapDisabledByTimeout ) {
            NSLog(@"event tap has timed out, re-enabling tap");
            [listener tapEvents];
            return nil;
        }
        if( type != kCGEventTapDisabledByUserInput ) {
            return [listener processEvent:event];
        }
    }
    return event;
}

// - - - - - - - - - - - - - - - - - - - - -

int main(int argc, const char * argv[])
{
    @autoreleasepool {
        KeyChanger* keyChanger = [KeyChanger new];
        [keyChanger tapEvents];
        [keyChanger listen];//blocking call.
    }
    return 0;
}

Answer 1

以下是您可以执行的操作的概述：

您设置了一个 IOHIDManager 并设置了输入匹配字典来匹配键盘。

然后 IOHIDManager 将为您提供对所有连接的键盘的引用作为 IOHIDDevices。

最后您可以为 IOHIDDevices 设置输入回调。现在您可以为每个设备单独输入回调！

设置和使用它有点麻烦，而且它不会像 CGEventTap 那样让您 filter/alter 事件。但这是我所知道的唯一一种监视输入的方法，这样您就可以知道哪个设备导致了哪个输入。

以下是一些起点：

IOHIDManager 文档

https://developer.apple.com/documentation/iokit/iohidmanager_h

IOHIDUsageTables.h 和 IOHIDDeviceKeys.h

对于键盘，您需要像这样声明匹配字典

NSDictionary *matchDict = @{
    @(kIOHIDDeviceUsagePageKey): @(kHIDPage_GenericDesktop),
    @(kIOHIDDeviceUsageKey): @(kHIDUsage_GD_Keyboard),
};

（然后通过免费桥接将其转换为 CFDictionaryRef）（不确定是否正确 - none 已测试）

在OSX中，如何判断哪个键盘产生了NSEvent？

In OSX, how to determine which keyboard generated an NSEvent?

macos

iokit

nsevent

keyboard-events