使用事件点击无法在某些应用程序上模拟退格按钮 [英] Can't simulate backspace button on some applications with event tap

问题描述

我正在尝试在Mac OS上模拟某些按键.如果按下'h'键(例如，如果用户键入'tigh'，它将变成'ti')，则该代码应通过修改键盘事件来删除前一个字符.但是，它仅适用于某些应用程序.其他人完全拒绝我的活动.这段代码有什么问题吗?

I'm trying to simulate some key presses on Mac OS. This code is supposed to delete one previous character if the 'h' key is pressed (e.g. if user types 'tigh' it will become 'ti') by modifying keyboard events. However it only works with some applications; others totally refuse my events. Is there any problem with this code ?

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
    CFMachPortRef      eventTap;
    CGEventMask        eventMask;
    CFRunLoopSourceRef runLoopSource;

    eventMask = ((1 << kCGEventKeyDown) | (1 << kCGEventKeyUp));

    eventTap = CGEventTapCreate(kCGSessionEventTap, kCGHeadInsertEventTap, 0,
                                eventMask, KeyHandler, NULL);
    if (!eventTap) {
        fprintf(stderr, "failed to create event tap\n");
        exit(1);
    }

    runLoopSource = CFMachPortCreateRunLoopSource(kCFAllocatorDefault, eventTap, 0);
    CFRunLoopAddSource(CFRunLoopGetCurrent(), runLoopSource, kCFRunLoopCommonModes);    
    CGEventTapEnable(eventTap, true);
    CFRunLoopRun();
}

CGEventRef KeyHandler(CGEventTapProxy proxy, CGEventType type, CGEventRef event, void *refcon)
{
    UniCharCount actualStringLength;
    UniCharCount maxStringLength = 1;    
    UniChar chars[3];

    CGEventKeyboardGetUnicodeString(event, maxStringLength, &actualStringLength, chars);

    if (chars[0] == 'h') {
        chars[0] = '\b';
        CGEventKeyboardSetUnicodeString(event, 1, chars);
        return event;        
    }

    return event;
}

推荐答案

某些应用程序根据事件(CGEventGetIntegerValueField(event, kCGKeyboardEventKeycode))的键代码而不是事件的UnicodeString来查找要键入的内容.

Some applications find what is being typed based on the key code from the event (CGEventGetIntegerValueField(event, kCGKeyboardEventKeycode)), rather than the event's UnicodeString.

也就是说，您需要将事件的kCGKeyboardEventKeycode值从"h"提供的 4 更新为 51 或( 0x33 )退格.

That is, you will need to update the event's kCGKeyboardEventKeycode value from the 4 supplied by "h" to 51 or (0x33) for Backspace.

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