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实现方法：

单独起一个线程，用于读取按键代码，读取后转换为Qt::Keys，然后使用

QApplication::postEvent((QObject*)tFocusObj,tTabKeyPress);

进行分发到当前具有焦点的窗体上。

#include "zkeypadthread.h"

ZKeyPadThread::ZKeyPadThread(QObject *parent) :     QObject(parent) {     this->m_udpSocket=new QUdpSocket;     connect(this->m_udpSocket,SIGNAL(readyRead()),this,SLOT(ZSlotReadUDPPacket())); } ZKeyPadThread::~ZKeyPadThread() {     delete this->m_udpSocket; } qint32 ZKeyPadThread::ZStartListen() {     if(this->m_udpSocket->bind(QHostAddress::Any,1986))     {         return 0;     }else{         return -1;     } } qint32 ZKeyPadThread::ZStopListen() {     this->m_udpSocket->disconnectFromHost();     this->m_udpSocket->close();     return 0; } void ZKeyPadThread::ZSlotReadUDPPacket() {     QByteArray tUDPSyncHeader("EAVKeyPad");     QByteArray tRecvBuffer;     tRecvBuffer.resize(this->m_udpSocket->pendingDatagramSize());     this->m_udpSocket->readDatagram(tRecvBuffer.data(),tRecvBuffer.size());     if(!tRecvBuffer.startsWith(tUDPSyncHeader))     {         qDebug()<<"unknow udp sync header!";         return;     }     qDebug()<<tRecvBuffer;     tRecvBuffer.remove(0,tUDPSyncHeader.size());     qDebug()<<tRecvBuffer;     for(qint32 i=0;i<tRecvBuffer.size();i++)     {         qDebug()<<tRecvBuffer.at(i);         qint32 tKeyCode=0;         switch(tRecvBuffer.at(i))         {         case ZKeyPadThread::ZKeyPad_Top:             tKeyCode=Qt::Key_Up;             break;         case ZKeyPadThread::ZKeyPad_Bottom:             tKeyCode=Qt::Key_Down;             break;         case ZKeyPadThread::ZKeyPad_Left:             tKeyCode=Qt::Key_Left;             break;         case ZKeyPadThread::ZKeyPad_Right:             tKeyCode=Qt::Key_Right;             break;         case ZKeyPadThread::ZKeyPad_Enter:             tKeyCode=Qt::Key_Enter;             break;         case ZKeyPadThread::ZKeyPad_Return:             tKeyCode=Qt::Key_Escape;             break;         default:             break;         }         //post key event.         QWidget *tFocusObj=QApplication::activeWindow();         if(tFocusObj)         {             QKeyEvent *tTabKeyPress=new QKeyEvent( QEvent::KeyPress,tKeyCode,Qt::NoModifier);             QApplication::postEvent((QObject*)tFocusObj,tTabKeyPress);         }     } } 然后在主窗体上使用二组数据组织各个部件，(x,y)，

根据上下左右控制x和y的+1或-1，然后赋予某个部件焦点。

#ifndef ZHOMENAVIGATOR_H

#define ZHOMENAVIGATOR_H #include <QFrame> #include <QGridLayout> #include <BaseParts/zcoolbutton.h> #include <MainUI/zfilemanager.h> #include <MainUI/zsystemsetup.h> #include <MainUI/zdatetimesetup.h> #include <Parameters/zparameters.h> #include <QHash> #include <QList> #include <QPoint> typedef struct {     QPoint pos;     QWidget *element; }ZKeyElement; class ZHomeNavigator : public QFrame {     Q_OBJECT public:     explicit ZHomeNavigator(QWidget *parent = 0);     ~ZHomeNavigator(); protected:     void keyPressEvent(QKeyEvent *event);     void keyReleaseEvent(QKeyEvent *event); signals:     void ZSignalReturnButtonClicked(); public slots:     void ZSlotShowFileManager();     void ZSlotShowSystemSetup();     void ZSlotShowDateTimeSetup(); private:     void ZAddWidgetToKeyList(qint32 x,qint32 y,QWidget *widget); private:     QToolButton *m_btnFileManager;     QToolButton *m_btnSysetmSetup;     QToolButton *m_btnWireless;     QToolButton *m_btnDateTime;     QToolButton *m_btnDevLog;     QToolButton *m_btnBattery;     QToolButton *m_btnSound;     QToolButton *m_btnShutdown;     QToolButton *m_btnReturn;     QGridLayout *m_gridLayout;     //keys move hash.     QList<ZKeyElement> m_keysList;     QPoint m_currentKey;     qint32 m_KeyRowCount;     qint32 m_KeyColCount; }; #endif // ZHOMENAVIGATOR_H

#include "zhomenavigator.h"

ZHomeNavigator::ZHomeNavigator(QWidget *parent) :     QFrame(parent) {     this->setObjectName("ZHomeNavigator");     this->setFocusPolicy(Qt::StrongFocus);     this->m_btnFileManager=new QToolButton;     this->m_btnFileManager->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);     this->m_btnFileManager->setIconSize(QSize(48,48));     this->m_btnFileManager->setIcon(QIcon(":/images/znavigator_filemanager.png"));     this->m_btnFileManager->setText(tr("Videos"));     connect(this->m_btnFileManager,SIGNAL(clicked()),this,SLOT(ZSlotShowFileManager()));     this->m_btnSysetmSetup=new QToolButton;     this->m_btnSysetmSetup->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);     this->m_btnSysetmSetup->setIconSize(QSize(48,48));     this->m_btnSysetmSetup->setIcon(QIcon(":/images/znavigator_setup.png"));     this->m_btnSysetmSetup->setText(tr("Settings"));     connect(this->m_btnSysetmSetup,SIGNAL(clicked()),this,SLOT(ZSlotShowSystemSetup()));     this->m_btnDateTime=new QToolButton;     this->m_btnDateTime->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);     this->m_btnDateTime->setIconSize(QSize(48,48));     this->m_btnDateTime->setIcon(QIcon(":/images/znavigator_datetime.png"));     this->m_btnDateTime->setText(tr("DateTime"));     connect(this->m_btnDateTime,SIGNAL(clicked()),this,SLOT(ZSlotShowDateTimeSetup()));     this->m_btnWireless=new QToolButton;     this->m_btnWireless->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);     this->m_btnWireless->setIconSize(QSize(48,48));     this->m_btnWireless->setIcon(QIcon(":/images/znavigator_wireless.png"));     this->m_btnWireless->setText(tr("Wireless"));     this->m_btnDevLog=new QToolButton;     this->m_btnDevLog->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);     this->m_btnDevLog->setIconSize(QSize(48,48));     this->m_btnDevLog->setIcon(QIcon(":/images/znavigator_devlog.png"));     this->m_btnDevLog->setText(tr("DevLog"));     this->m_btnBattery=new QToolButton;     this->m_btnBattery->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);     this->m_btnBattery->setIconSize(QSize(48,48));     this->m_btnBattery->setIcon(QIcon(":/images/znavigator_battery.png"));     this->m_btnBattery->setText(tr("Battery"));     this->m_btnSound=new QToolButton;     this->m_btnSound->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);     this->m_btnSound->setIconSize(QSize(48,48));     this->m_btnSound->setIcon(QIcon(":/images/znavigator_sound.png"));     this->m_btnSound->setText(tr("Sound"));     this->m_btnShutdown=new QToolButton;     this->m_btnShutdown->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);     this->m_btnShutdown->setIconSize(QSize(48,48));     this->m_btnShutdown->setIcon(QIcon(":/images/znavigator_shutdown.png"));     this->m_btnShutdown->setText(tr("Shutdown"));     this->m_btnReturn=new QToolButton;     this->m_btnReturn->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);     this->m_btnReturn->setIconSize(QSize(48,48));     this->m_btnReturn->setIcon(QIcon(":/images/znavigator_return.png"));     this->m_btnReturn->setText(tr("Return"));     connect(this->m_btnReturn,SIGNAL(clicked()),this,SIGNAL(ZSignalReturnButtonClicked()));     //layout.     this->m_gridLayout=new QGridLayout;     this->m_gridLayout->addWidget(this->m_btnFileManager,0,0,1,1);     this->m_gridLayout->addWidget(this->m_btnSysetmSetup,0,1,1,1);     this->m_gridLayout->addWidget(this->m_btnDateTime,0,2,1,1);     this->m_gridLayout->addWidget(this->m_btnWireless,0,3,1,1);     this->m_gridLayout->addWidget(this->m_btnDevLog,0,4,1,1);     this->m_gridLayout->addWidget(this->m_btnBattery,1,0,1,1);     this->m_gridLayout->addWidget(this->m_btnSound,1,1,1,1);     this->m_gridLayout->addWidget(this->m_btnShutdown,1,3,1,1);     this->m_gridLayout->addWidget(this->m_btnReturn,1,4,1,1);     //layout.     this->setLayout(this->m_gridLayout);     //arrange the widgets to control by keys.     this->ZAddWidgetToKeyList(0,0,this->m_btnFileManager);     this->ZAddWidgetToKeyList(0,1,this->m_btnSysetmSetup);     this->ZAddWidgetToKeyList(0,2,this->m_btnDateTime);     this->ZAddWidgetToKeyList(0,3,this->m_btnWireless);     this->ZAddWidgetToKeyList(0,4,this->m_btnDevLog);     this->ZAddWidgetToKeyList(1,0,this->m_btnBattery);     this->ZAddWidgetToKeyList(1,1,this->m_btnSound);     this->ZAddWidgetToKeyList(1,3,this->m_btnShutdown);     this->ZAddWidgetToKeyList(1,4,this->m_btnReturn);     //the initial key element is (0,0) at default.     this->m_currentKey=QPoint(0,0);     this->m_KeyRowCount=2;//count from 1 not 0.     this->m_KeyColCount=5;//count from 1 not 0. } ZHomeNavigator::~ZHomeNavigator() {     delete this->m_btnFileManager;     delete this->m_btnSysetmSetup;     delete this->m_btnDateTime;     delete this->m_btnWireless;     delete this->m_btnDevLog;     delete this->m_btnBattery;     delete this->m_btnSound;     delete this->m_btnShutdown;     delete this->m_btnReturn;     delete this->m_gridLayout; } void ZHomeNavigator::ZAddWidgetToKeyList(qint32 x,qint32 y,QWidget *widget) {     ZKeyElement tKeyElement;     tKeyElement.pos=QPoint(x,y);     tKeyElement.element=widget;     this->m_keysList.append(tKeyElement); } void ZHomeNavigator::ZSlotShowFileManager() {     ZFileManager tFileManager;     tFileManager.setGeometry(this->geometry());     tFileManager.exec(); } void ZHomeNavigator::ZSlotShowSystemSetup() {     ZSystemSetup tSystemSetup;     tSystemSetup.setGeometry(this->geometry());     //capture delay.     tSystemSetup.ZSetLicensePlateCaptureDelay(gGlobalParam.licencePlateCaptureDelay);     tSystemSetup.ZSetGoodsVideoCaptureDelay(gGlobalParam.goodsVideoCaptureDelay);     //tcp server.     tSystemSetup.ZSetTcpServerIPAddr(gGlobalParam.tcpServerIP);     tSystemSetup.ZSetTcpServerPort(gGlobalParam.tcpServerPort);     if(tSystemSetup.exec()==QDialog::Accepted)     {         //update the delay parameter.         gGlobalParam.licencePlateCaptureDelay=tSystemSetup.ZGetLicensePlateCaptureDelay();         gGlobalParam.goodsVideoCaptureDelay=tSystemSetup.ZGetGoodsVideoCaptureDelay();         //tcp server.         gGlobalParam.tcpServerIP=tSystemSetup.ZGetTcpServerIPAddr();         gGlobalParam.tcpServerPort=tSystemSetup.ZGetTcpServerPort();     } } void ZHomeNavigator::ZSlotShowDateTimeSetup() {     ZDateTimeSetup tDateTimeSetup;     tDateTimeSetup.setGeometry(this->geometry());     tDateTimeSetup.exec(); } void ZHomeNavigator::keyPressEvent(QKeyEvent *event) {     switch(event->key())     {     case Qt::Key_Up:         if(this->m_currentKey.x()>0)         {             this->m_currentKey.setX(this->m_currentKey.x()-1);         }         break;     case Qt::Key_Down:         if(this->m_currentKey.x()<this->m_KeyRowCount-1)         {            this->m_currentKey.setX(this->m_currentKey.x()+1);         }         break;     case Qt::Key_Left:         if(this->m_currentKey.y()>0)         {             this->m_currentKey.setY(this->m_currentKey.y()-1);         }         break;     case Qt::Key_Right:         if(this->m_currentKey.y()<this->m_KeyColCount-1)         {             this->m_currentKey.setY(this->m_currentKey.y()+1);         }         break;     }    //find the specified widget.     for(qint32 i=0;i<this->m_keysList.count();i++)     {         ZKeyElement tKeyElement=this->m_keysList.at(i);         if(tKeyElement.pos==this->m_currentKey)         {             tKeyElement.element->setFocus();             break;         }     } } void ZHomeNavigator::keyReleaseEvent(QKeyEvent *event) {     qDebug()<<"release"; }

某个部件具有焦点时，使用QToolButton:focus来进行qss美化工作。

app.setStyleSheet("QToolButton:focus{background-color:green;}");