objective-c - 如何使用UCKeyTranslate

给定一个不带修饰符的按键代码，我想产生按shift + key的结果。示例:对于标准的美国键盘， + 给出>。

相关的函数是UCKeytranslate，但是我需要一些帮助来确保细节正确。下面的代码段是一个完整的程序，准备在Xcode中运行。给出程序的意图是来产生字符>。

该程序的结果是:

Keyboard: <TSMInputSource 0x10051a930> KB Layout: U.S. (id=0)
Layout: 0x0000000102802000
Status: -50
UnicodeString: 97
String: a
Done
Program ended with exit code: 0

获得布局的零件似乎正在工作，但是状态代码表明出了点问题。但是呢

import Foundation
import Cocoa
import Carbon
import AppKit

// The current text input source (read keyboard) has a layout in which
// we can lookup how key-codes are resolved.

// Get the a reference keyboard using the current layout.
var unmanagedKeyboard = TISCopyCurrentKeyboardLayoutInputSource()
var keyboard = unmanagedKeyboard.takeUnretainedValue() as TISInputSource
print("Keyboard: ") ; println(keyboard)

// Get the layout
var ptrLayout   = TISGetInputSourceProperty(keyboard, kTISPropertyUnicodeKeyLayoutData)
var layout = UnsafeMutablePointer<UCKeyboardLayout>(ptrLayout)
print("Layout: "); println(layout)

// Let's see what the result of pressing  <shift> and <period>  (hopefully the result is > )
var keycode             = UInt16(kVK_ANSI_Period)                           // Keycode for <period>
var keyaction           = UInt16(kUCKeyActionDisplay)                       // The user is requesting information for key display
var modifierKeyState    = UInt32(1 << 17)                                   // Shift
var keyboardType        = UInt32(LMGetKbdType())
var keyTranslateOptions = UInt32(1 << kUCKeyTranslateNoDeadKeysBit)
var deadKeyState        = UnsafeMutablePointer<UInt32>(bitPattern: 0)       // Is 0 the correct value?
var maxStringLength     = UniCharCount(4)                                   // uint32
var actualStringLength  = UnsafeMutablePointer<UniCharCount>.alloc(1)       //
actualStringLength[0]=16
var unicodeString       = UnsafeMutablePointer<UniChar>.alloc(255)
unicodeString[0] = 97 // a (this value is meant to be overwritten by UCKeyTranslate)
var str = NSString(characters: unicodeString, length: 1)
var result = UCKeyTranslate(layout, keycode, keyaction, modifierKeyState, keyboardType, keyTranslateOptions,
                            deadKeyState, maxStringLength, actualStringLength, unicodeString)

// Print the results
print("Status: "); println(result)
var unichar = unicodeString[0];
print("UnicodeString: "); println(String(unichar))
print("String: "); println(str)
println("Done")

编辑

我已按照Ken Thomases的建议重写了代码段。
来自的一些技巧:Graphite还使用了一个使用键码的Swift程序。

import Foundation
import Cocoa
import Carbon
import AppKit

// The current text input source (read keyboard) has a layout in which
// we can lookup how key-codes are resolved.

// Get the a reference keyboard using the current layout.
let keyboard = TISCopyCurrentKeyboardInputSource().takeRetainedValue()
let rawLayoutData = TISGetInputSourceProperty(keyboard, kTISPropertyUnicodeKeyLayoutData)
print("Keyboard: ") ; println(keyboard)

// Get the layout
var layoutData      = unsafeBitCast(rawLayoutData, CFDataRef.self)
var layout: UnsafePointer<UCKeyboardLayout> = unsafeBitCast(CFDataGetBytePtr(layoutData), UnsafePointer<UCKeyboardLayout>.self)
print("Layout: "); println(layout)

print("KbdType "); println(LMGetKbdType()) // Sanity check (prints 44)

var keycode             = UInt16(kVK_ANSI_Period)                         // Keycode for a
var keyaction           = UInt16(kUCKeyActionDisplay)
var modifierKeyState    = UInt32(1 << 1)                                  // Shift
var keyboardType        = UInt32(LMGetKbdType())
var keyTranslateOptions = OptionBits(kUCKeyTranslateNoDeadKeysBit)
var deadKeyState        = UInt32(0)                                       // Is 0 the correct value?
var maxStringLength     = UniCharCount(4)                                 // uint32
var chars: [UniChar]    = [0,0,0,0]
var actualStringLength  = UniCharCount(1)
var result = UCKeyTranslate(layout, keycode, keyaction, modifierKeyState, keyboardType, keyTranslateOptions,
                            &deadKeyState, maxStringLength, &actualStringLength, &chars)
// Print the results
print("Status: "); println(result)
print("Out:"); println(UnicodeScalar(chars[0]))
println("Done")

最佳答案

对于kTISPropertyUnicodeKeyLayoutData，TISGetInputSourceProperty()返回CFDataRef。您需要获取其字节指针，并将其视为UCKeyboardLayout的指针。我不认为这是您在此行中所做的:

var layout = UnsafeMutablePointer<UCKeyboardLayout>(ptrLayout)

我不太了解Swift，但是它可能会像这样工作:

var layout = UnsafePointer<UCKeyboardLayout>(CFDataGetBytePtr(ptrLayout))

或许:

var layout = CFDataGetBytePtr(ptrLayout) as UnsafePointer<UCKeyboardLayout>

另外，kUCKeyActionDisplay几乎没有用。其目的是返回键的标签，但它甚至不能可靠地返回键。您可能要使用kUCKeyActionDown。

对于修饰符，您想使用Carbon时代的shiftKey位掩码向右移8位(如UCKeyTranslate()的文档中所示)。 shiftKey是1 << 9，所以shiftKey >> 8是1 << 1。

对于这些选项，为简单起见，您应该可以使用kUCKeyTranslateNoDeadKeysMask。它等效于1 << kUCKeyTranslateNoDeadKeysBit。

是的，对于初始击键或不想应用任何先前的死键状态的deadKeyState，0是正确的值。

我不确定您为什么用maxStringLength注释了uint32行。该类型与最大字符串长度完全无关。 maxStringLength是UCKeyTranslate()应该写入提供的缓冲区的UTF-16代码单元的最大数量(API将其错误地称为“字符”)。它基本上是缓冲区大小，以UniChar s(不是字节)为单位。在您的情况下，它应该为255。或者，由于您可能不希望从单个击键中获得255个“字符”，因此可以减小缓冲区的大小，并设置maxStringLength使其匹配。

您对str的处理很奇怪。您可以在调用unicodeString之前从UCKeyTranslate()缓冲区构造它。您是否希望因为UCKeyTranslate()更改unicodeString的内容而更改字符串对象的值？它不是。如果确实如此，那将是NSString中的一个非常糟糕的错误。在 NSString成功填充该缓冲区之后，您应该从缓冲区构造UCKeyTranslate()。当然，在构造actualStringLength时，应将NSString作为length参数传递。