使用IOHIDManager获取修饰符键事件 [英] Using IOHIDManager to Get Modifier Key Events

问题描述

我正在尝试使用IOHIDManager来获取修饰键事件，因为缺少可可flagsChanged事件(难以区分新闻/发布，左/右，如果两者都按下等).这是我在其中创建管理器和注册回调.

I'm trying to use IOHIDManager to get modifier key events because Cocoa flagsChanged events are lacking (difficult to differentiate between press/release, left/right if both are down, etc.) Here's the code where I create the manager and register the callback.

IOHIDManagerRef hidManager = IOHIDManagerCreate(kCFAllocatorDefault,
        kIOHIDOptionsTypeNone);
if (CFGetTypeID(hidManager) != IOHIDManagerGetTypeID())
    return 1;

CFMutableDictionaryRef capsLock =
    myCreateDeviceMatchingDictionary(0x07, 0x39);
CFMutableDictionaryRef lctrl =
    myCreateDeviceMatchingDictionary(0x07, 0xE0);
CFMutableDictionaryRef lshift =
    myCreateDeviceMatchingDictionary(0x07, 0xE1);
CFMutableDictionaryRef lalt =
    myCreateDeviceMatchingDictionary(0x07, 0xE2);
CFMutableDictionaryRef lsuper =
    myCreateDeviceMatchingDictionary(0x07, 0xE3);
CFMutableDictionaryRef rctrl =
    myCreateDeviceMatchingDictionary(0x07, 0xE4);
CFMutableDictionaryRef rshift =
    myCreateDeviceMatchingDictionary(0x07, 0xE5);
CFMutableDictionaryRef ralt =
    myCreateDeviceMatchingDictionary(0x07, 0xE6);
CFMutableDictionaryRef rsuper =
    myCreateDeviceMatchingDictionary(0x07, 0xE7);

CFMutableDictionaryRef matchesList[] = {
    capsLock,
    lctrl,
    lshift,
    lalt,
    lsuper,
    rctrl,
    rshift,
    ralt,
    rsuper
};
CFArrayRef matches = CFArrayCreate(kCFAllocatorDefault,
        (const void **)matchesList, 9, NULL);
IOHIDManagerSetDeviceMatchingMultiple(hidManager, matches);

IOHIDManagerRegisterInputValueCallback(hidManager,
        myHandleModifiersCallback, NULL);

IOHIDManagerScheduleWithRunLoop(hidManager, CFRunLoopGetMain(),
        kCFRunLoopDefaultMode);

IOHIDManagerOpen(hidManager, kIOHIDOptionsTypeNone);

但是，回调从未运行过.我想念什么吗?

However, the callback is never being run. Am I missing anything?

我不完全了解HID使用情况页面，因此我不知道是否要使用具有键盘使用情况ID(06)的通用桌面页面(0x01)或具有使用情况ID的键盘/键盘页面(0x07)对于单个键.也许与它有关吗?

I don't fully understand HID usage pages, so I didn't know whether or not to use Generic Desktop Page (0x01) with the keyboard usage ID (06) or the Keyboard/Keypad Page (0x07) with Usage IDs for the individual keys. Maybe that has something to do with it?

推荐答案

我知道了.这样做的方法是将通用桌面页面(0x01)键盘(06)(和键盘(07)完整)与IOHIDManagerSetDeviceMatchingMultiple一起使用，然后输入值回调获取键盘/键盘使用情况页面(0x07).

I figured it out. The way to do it is to use the Generic Desktop Page (0x01) Keyboard (06) (and Keypad (07) for completeness) for use with IOHIDManagerSetDeviceMatchingMultiple, and then the input value callback gets Keyboard/Keypad Usage Page (0x07) stuff.

例如，要为所有键盘/键盘设置一个HIDManager，可以执行以下操作:

For example, to setup a an HIDManager for all keyboards/keypads, one could do something like:

IOHIDManagerRef hidManager = IOHIDManagerCreate(kCFAllocatorDefault,
        kIOHIDOptionsTypeNone);

CFMutableDictionaryRef keyboard =
    myCreateDeviceMatchingDictionary(0x01, 6);
CFMutableDictionaryRef keypad =
    myCreateDeviceMatchingDictionary(0x01, 7);

CFMutableDictionaryRef matchesList[] = {
    keyboard,
    keypad,
};
CFArrayRef matches = CFArrayCreate(kCFAllocatorDefault,
        (const void **)matchesList, 2, NULL);
IOHIDManagerSetDeviceMatchingMultiple(hidManager, matches);

IOHIDManagerRegisterInputValueCallback(hidManager,
        myHIDKeyboardCallback, NULL);

IOHIDManagerScheduleWithRunLoop(hidManager, CFRunLoopGetMain(),
        kCFRunLoopDefaultMode);

IOHIDManagerOpen(hidManager, kIOHIDOptionsTypeNone);

myCreateDeviceMatchingDictionary类似于:

Where myCreateDeviceMatchingDictionary is something like:

CFMutableDictionaryRef myCreateDeviceMatchingDictionary(UInt32 usagePage,
        UInt32 usage) {
    CFMutableDictionaryRef ret = CFDictionaryCreateMutable(kCFAllocatorDefault,
            0, &kCFTypeDictionaryKeyCallBacks,
            &kCFTypeDictionaryValueCallBacks);
    if (!ret)
        return NULL;

    CFNumberRef pageNumberRef = CFNumberCreate(kCFAllocatorDefault,
            kCFNumberIntType, &usagePage );
    if (!pageNumberRef) {
        CFRelease(ret);
        return NULL;
    }

    CFDictionarySetValue(ret, CFSTR(kIOHIDDeviceUsagePageKey), pageNumberRef);
    CFRelease(pageNumberRef);

    CFNumberRef usageNumberRef = CFNumberCreate(kCFAllocatorDefault,
            kCFNumberIntType, &usage);
    if (!usageNumberRef) {
        CFRelease(ret);
        return NULL;
    }

    CFDictionarySetValue(ret, CFSTR(kIOHIDDeviceUsageKey), usageNumberRef);
    CFRelease(usageNumberRef);

    return ret;
}

myHIDKeyboardCallback类似于:

And myHIDKeyboardCallback is something like:

void myHIDKeyboardCallback(void *context, IOReturn result, void *sender,
        IOHIDValueRef value) {
    IOHIDElementRef elem = IOHIDValueGetElement(value);
    if (IOHIDElementGetUsagePage(elem) != 0x07)
        return;
    uint32_t scancode = IOHIDElementGetUsage(elem);
    if (scancode < 4 || scancode > 231)
        return;
    long pressed = IOHIDValueGetIntegerValue(value);
    // ... Do something ...
}

请注意，每次按下或释放时，似乎多次调用该回调，但是用法ID在正常范围之外，这就是"if(scancode< 4 || scancode> 231)"的含义.

Note that the callback seems to be called multiple times per press or release but with usage IDs outside the normal range, which is what the "if (scancode < 4 || scancode > 231)" is for.

这篇关于使用IOHIDManager获取修饰符键事件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！