在Qt/Embedded 2.3.8中添加MX21Ads键盘处理

经过查看源代码发现Qt的键盘处理是判断环境变量QWS_KEYBOARD再加载相应的键盘处理拦截类,  而qt已经包含了几个典型的键盘处理,只要以它们为蓝本即可编写自己的处理类! 一下我以 vr4xx为模板, 建立QWSMx21ButtonsHandler键盘处理类! 以下是相关实现代码,

2. 添加键盘处理类
class QWSMx21ButtonsHandler : public QWSKeyboardHandler
{
    Q_OBJECT
public:
    QWSMx21ButtonsHandler();
    virtual QWSMx21ButtonsHandler();

    bool isOpen() { return buttonFD > 0; }

private slots:
    void readKeyboardData();  // 这个函数最重要, 包含的读键盘扫描码的处理

private:
    QString terminalName;
    int buttonFD;
    int kbdIdx;
    int kbdBufferLen;
    unsigned char *kbdBuffer;
    QSocketNotifier *notifier;
};
/*
 * mx21 buttons driver
 */

QWSMx21ButtonsHandler::QWSMx21ButtonsHandler() : QWSKeyboardHandler()
{
    terminalName = "/dev/buttons";
    buttonFD = -1;
    notifier = 0;

    if ((buttonFD = open(terminalName, O_RDWR | O_NDELAY, 0)) < 0)
    {
    qWarning("Cannot open %s/n", terminalName.latin1());
    }

    if ( buttonFD >= 0 ) {
    notifier = new QSocketNotifier( buttonFD, QSocketNotifier::Read, this );
    connect( notifier, SIGNAL(activated(int)),this,
         SLOT(readKeyboardData()) );
    }

    kbdBufferLen = 80;
    kbdBuffer = new unsigned char [kbdBufferLen];
    kbdIdx = 0;
}

QWSMx21ButtonsHandler::~QWSMx21ButtonsHandler()
{
    if ( buttonFD > 0 ) {
    ::close( buttonFD );
    buttonFD = -1;
    }
    delete notifier;
    notifier = 0;
    delete [] kbdBuffer;
}

void QWSMx21ButtonsHandler::readKeyboardData()
{

    int n = 0;
    do {
    n  = read(buttonFD, kbdBuffer+kbdIdx, kbdBufferLen - kbdIdx );
    if ( n > 0 )
        kbdIdx += n;
    } while ( n > 0 );

    int idx = 0;
    while ( kbdIdx - idx >= 2 ) {
        unsigned char *next = kbdBuffer + idx;
        unsigned short *code = (unsigned short *)next;

        if ( ( *code & 0x8000) != 0x8000) {
            idx += 2;
            continue;
        }
        int keycode = Qt::Key_unknown;
       //在此添加键盘扫描码映射关系
        switch ( (*code) & 0x00ff ) {
            case 59:
            keycode = Qt::Key_Up;
            break;          
            default:
            qDebug("Unrecognised key sequence %d", (int)code );
        }
            processKeyEvent( 0, keycode, 0, TRUE, FALSE );
        idx += 2;
    }

    int surplus = kbdIdx - idx;
    for ( int i = 0; i < surplus; i++ )
    kbdBuffer[i] = kbdBuffer[idx+i];
    kbdIdx = surplus;
}

2. 添加加载代码
src/kernel/qkeyboard_qws.cpp
/*
 * keyboard driver instantiation
 */

QWSKeyboardHandler *QWSServer::newKeyboardHandler( const QString &spec )
{
    QWSKeyboardHandler *handler = 0;

    QString device;
    QString type;
    int colon=spec.find(':');
    if ( colon>=0 ) {
    type = spec.left(colon);
    device = spec.mid(colon+1);
    } else {
    type = spec;
    }

    if ( type == "Buttons" ) {
#if defined(QT_QWS_YOPY)
    handler = new QWSyopyButtonsHandler();
#elif defined(QT_QWS_CASSIOPEIA)
    handler = new QWSVr41xxButtonsHandler();
#endif
    } else if ( type == "QVFbKeyboard" ) {
    handler = new QWSVFbKeyboardHandler();
    } else if ( type == "USB" ) {
    handler = new QWSUsbKeyboardHandler(device);
    } else if ( type == "TTY" ) {
    handler = new QWSTtyKeyboardHandler(device);
    } else if ( type == "MX21" ) {   //这是我们添加的MX21键盘处理类
    handler = new QWSMx21ButtonsHandler();
    } else {
    qWarning( "Keyboard type %s:%s unsupported", spec.latin1(), device.latin1() );
    }

    return handler;
}
3.重新编译链接
在目标平台上只要设置QWS_KEYBOARD=MX21即可在界面中拦截到键盘事件处理! 
这里只是给出了基本原理实现,具体的键盘扫瞄码映射关系得看具体的操作!
最新的qtopia-core 版本也可以参考Vr4xx 实现来做, 在src/gui/embedded/下!

希望对有需要的人有所帮助!