Mac OS 虚拟键盘的一些问题。（CGKeyCode）
最近有一个需求，做一个虚拟键盘，用户点击虚拟键盘来代替键盘输入，一想挺简单的，大概一个实现思路就是模拟键盘来发送CGKeyCode 大致思路就是
#include
#include
CGEventRef key = CGEventCreateKeyboardEvent(NULL, (CGKeyCode)code, true);
CGEventPost(kCGHIDEventTap, key);
CFRelease(key); 做完后发现虽然是实现了需求，但是却会弹出一个权限提示 这样需要用给给应用辅助功能的权限。万一用户不给到这个权限，这虚拟键盘就不能用了，这个思路就行不通了。
后来的一种方法。实现NSTextFieldDelegate在此回调中监听当前NSTextField的光标位置来向其stringValue插入字符实现虚拟键盘
- (nullable NSArray *)textField:(NSTextField *)textField textView:(NSTextView *)textView candidatesForSelectedRange:(NSRange)selectedRange NS_AVAILABLE_MAC(10_12_2);
//获取当前光标的位置
selectedRange.location然后发现有2点问题。1.在鼠标没有点击NSTextField的时候，插入字符NSTextField是全选状态不美观。2.NSTextField失去第一响应者的时候无法正确获取到光标位置。
思索一会儿后决定人为的来控制光标
NSInteger index;//当前光标的位置
NSTextField *textField;//当前输入框
//当textField第一次插入字符的时候 将textField的光标设置到后边去，避免了输入框全选的情况
NSRange rr = NSMakeRange(1, 0);
textField.currentEditor.selectedRange = rr;
index = textField.currentEditor.selectedRange.location;
//以后的每次输入都要将光标移动当前字符的后边
NSRange rr = NSMakeRange(index+1, 0);
textField.currentEditor.selectedRange = rr;
index = textField.currentEditor.selectedRange.location;
//删除的时候也要记得把光标位置挪到删除字符的前边
if (index == 0) {
textField.stringValue = [textField.stringValue substringWithRange:NSMakeRange(0, [textField.stringValue length] - 1)];
index = 0;
}else {
index = textField.currentEditor.selectedRange.location;
NSMutableString *confStr = [NSMutableString textField.stringValue];
[confStr deleteCharactersInRange:NSMakeRange(index-1, 1)];
textField.stringValue = confStr;
NSRange rr = NSMakeRange(index-1, 0);
textField.currentEditor.selectedRange = rr;
}
这样一来就大概的实现了虚拟键盘的输入。实测跟点击键盘一个效果～
附贴上CGKeyCode对照表：
/*
* Summary:
* Virtual keycodes
*
* Discussion:
* These constants are the virtual keycodes defined originally in
* Inside Mac Volume V, pg. V-191. They identify physical keys on a
* keyboard. Those constants with "ANSI" in the name are labeled
* according to the key position on an ANSI-standard US keyboard.
* For example, kVK_ANSI_A indicates the virtual keycode for the key
* with the letter 'A' in the US keyboard layout. Other keyboard
* layouts may have the 'A' key label on a different physical key;
* in this case, pressing 'A' will generate a different virtual
* keycode.
*/
enum {
kVK_ANSI_A = 0x00,
kVK_ANSI_S = 0x01,
kVK_ANSI_D = 0x02,
kVK_ANSI_F = 0x03,
kVK_ANSI_H = 0x04,
kVK_ANSI_G = 0x05,
kVK_ANSI_Z = 0x06,
kVK_ANSI_X = 0x07,
kVK_ANSI_C = 0x08,
kVK_ANSI_V = 0x09,
kVK_ANSI_B = 0x0B,
kVK_ANSI_Q = 0x0C,
kVK_ANSI_W = 0x0D,
kVK_ANSI_E = 0x0E,
kVK_ANSI_R = 0x0F,
kVK_ANSI_Y = 0x10,
kVK_ANSI_T = 0x11,
kVK_ANSI_1 = 0x12,
kVK_ANSI_2 = 0x13,
kVK_ANSI_3 = 0x14,
kVK_ANSI_4 = 0x15,
kVK_ANSI_6 = 0x16,
kVK_ANSI_5 = 0x17,
kVK_ANSI_Equal = 0x18,
kVK_ANSI_9 = 0x19,
kVK_ANSI_7 = 0x1A,
kVK_ANSI_Minus = 0x1B,
kVK_ANSI_8 = 0x1C,
kVK_ANSI_0 = 0x1D,
kVK_ANSI_RightBracket = 0x1E,
kVK_ANSI_O = 0x1F,
kVK_ANSI_U = 0x20,
kVK_ANSI_LeftBracket = 0x21,
kVK_ANSI_I = 0x22,
kVK_ANSI_P = 0x23,
kVK_ANSI_L = 0x25,
kVK_ANSI_J = 0x26,
kVK_ANSI_Quote = 0x27,
kVK_ANSI_K = 0x28,
kVK_ANSI_Semicolon = 0x29,
kVK_ANSI_Backslash = 0x2A,
kVK_ANSI_Comma = 0x2B,
kVK_ANSI_Slash = 0x2C,
kVK_ANSI_N = 0x2D,
kVK_ANSI_M = 0x2E,
kVK_ANSI_Period = 0x2F,
kVK_ANSI_Grave = 0x32,
kVK_ANSI_KeypadDecimal = 0x41,
kVK_ANSI_KeypadMultiply = 0x43,
kVK_ANSI_KeypadPlus = 0x45,
kVK_ANSI_KeypadClear = 0x47,
kVK_ANSI_KeypadDivide = 0x4B,
kVK_ANSI_KeypadEnter = 0x4C,
kVK_ANSI_KeypadMinus = 0x4E,
kVK_ANSI_KeypadEquals = 0x51,
kVK_ANSI_Keypad0 = 0x52,
kVK_ANSI_Keypad1 = 0x53,
kVK_ANSI_Keypad2 = 0x54,
kVK_ANSI_Keypad3 = 0x55,
kVK_ANSI_Keypad4 = 0x56,
kVK_ANSI_Keypad5 = 0x57,
kVK_ANSI_Keypad6 = 0x58,
kVK_ANSI_Keypad7 = 0x59,
kVK_ANSI_Keypad8 = 0x5B,
kVK_ANSI_Keypad9 = 0x5C
};
/* keycodes for keys that are independent of keyboard layout*/
enum {
kVK_Return = 0x24,
kVK_Tab = 0x30,
kVK_Space = 0x31,
kVK_Delete = 0x33,
kVK_Escape = 0x35,
kVK_Command = 0x37,
kVK_Shift = 0x38,
kVK_CapsLock = 0x39,
kVK_Option = 0x3A,
kVK_Control = 0x3B,
kVK_RightCommand = 0x36,
kVK_RightShift = 0x3C,
kVK_RightOption = 0x3D,
kVK_RightControl = 0x3E,
kVK_Function = 0x3F,
kVK_F17 = 0x40,
kVK_VolumeUp = 0x48,
kVK_VolumeDown = 0x49,
kVK_Mute = 0x4A,
kVK_F18 = 0x4F,
kVK_F19 = 0x50,
kVK_F20 = 0x5A,
kVK_F5 = 0x60,
kVK_F6 = 0x61,
kVK_F7 = 0x62,
kVK_F3 = 0x63,
kVK_F8 = 0x64,
kVK_F9 = 0x65,
kVK_F11 = 0x67,
kVK_F13 = 0x69,
kVK_F16 = 0x6A,
kVK_F14 = 0x6B,
kVK_F10 = 0x6D,
kVK_F12 = 0x6F,
kVK_F15 = 0x71,
kVK_Help = 0x72,
kVK_Home = 0x73,
kVK_PageUp = 0x74,
kVK_ForwardDelete = 0x75,
kVK_F4 = 0x76,
kVK_End = 0x77,
kVK_F2 = 0x78,
kVK_PageDown = 0x79,
kVK_F1 = 0x7A,
kVK_LeftArrow = 0x7B,
kVK_RightArrow = 0x7C,
kVK_DownArrow = 0x7D,
kVK_UpArrow = 0x7E
};
/* ISO keyboards only*/
enum {
kVK_ISO_Section = 0x0A
};
/* JIS keyboards only*/
enum {
kVK_JIS_Yen = 0x5D,
kVK_JIS_Underscore = 0x5E,
kVK_JIS_KeypadComma = 0x5F,
kVK_JIS_Eisu = 0x66,
kVK_JIS_Kana = 0x68
};