qt 處理序間通訊

Qt中仍可以利用傳統的處理序間通訊方式(共用記憶體..)
· 在案頭環境中,在傳統的處理序間通訊方式的基礎上發展了更為方便的物件導向的通訊方式
-
KDE環境:DCOP
-
GNOME環境:Bonobo
· DBUS:freedesktop開源項目的Linux IPC通訊機制,KDE和GNOME環境都能支援
· Qt Embedded中定義了一種自己的輕量級的處理序間通訊機制QCOP

QCOP:
· QCOP利用QcopChannel類來實現.
· QcopChannel從Qobject類繼承而來
-
提供了靜態函數send()來發送需要傳遞的訊息和資料
-
靜態函數isRegistered()來查詢某個Channel是否已經被註冊
-
當從channel中接收訊息和資料時,我們需要構造一個QcopChannel的子類並重寫receive()函數,或者提供一個槽並利用connect()函數將receive()訊號串連起來
·利用QCOP可以方便的結合qt本身的訊號和槽的機制,使用非常方便
·但對於非QT程式與Qt程式的通訊,則只能使用其他IPC方式
QCOP樣本:
在一個進程中發送訊息和資料:

QbyteArray data; QdataStream out(&data,QIODevice::WriteOnly); out<<celNum; QcopChannel::send(“/System/Temperature”,”ConvertCelTOFah(int)”,data);

在另一個進程中接收訊息和資料:

QcopChannel *channel=new QcopChannel(“/System/Temperature”,this); connect(channel,SIGNAL(received(const Qstring &, constQbyteArray&)), this,SLOT(handleMsg(const Qstring&,const QbyteArray&)));

下面是一個樣本:

//CopServ.h 作為服務端運行 –qws #ifndef CONVERSION_SCREEN_H #define CONVERSION_SCREEN_H #include <QWidget> class CopServ : public QWidget { Q_OBJECT public: CopServ(); ~CopServ() {}; private slots: void launchFah(); void launchCel(); private: void createScreen(); void launchApp(const char* path); }; #endif //CONVERSION_SCREEN_H //CopServ.cpp程式主體 #include <QPushButton> #include <QSlider> #include <QLabel> #include <QDial> #include <QLCDNumber> #include <QVBoxLayout> #include <QHBoxLayout> #include <QGridLayout> #include <QSettings> #include <QApplication> #include <QCoreApplication> #include <unistd.h> #include <sys/types.h> #include "CopServ.h" CopServ::CopServ() : QWidget() { createScreen(); } void CopServ::createScreen() { QPushButton* celBtn = new QPushButton("Cel"); QPushButton* fahBtn = new QPushButton("Fah"); QPushButton* quitBtn = new QPushButton("Quit"); QGridLayout *mainLayout = new QGridLayout; mainLayout->addWidget(celBtn, 0, 0); mainLayout->addWidget(fahBtn, 0, 1); mainLayout->addWidget(quitBtn, 1, 0); setLayout(mainLayout); connect(celBtn, SIGNAL(clicked()), this, SLOT(launchCel())); connect(fahBtn, SIGNAL(clicked()), this, SLOT(launchFah())); connect(quitBtn, SIGNAL(clicked()), qApp, SLOT(quit())); setGeometry(0, 50, 240, 320); setWindowTitle("Server Window"); } void CopServ::launchApp(const char* path) //啟動子程式 { if (path == NULL) { qDebug("Launch path is NULL!/n"); } pid_t pid = fork(); //建立子進程 if (pid == 0) { qDebug("new process forked. PID is:%d/n", getpid()); int result = execl(path, path, 0); if (result < 0) { qDebug("failed to launch application!/n"); } _exit(-1); } } void CopServ::launchCel() { launchApp("./cel/cel"); } void CopServ::launchFah() { launchApp("./fah/fah"); } //main.cpp #include <QApplication> #include "CopServ.h" int main(int argc, char *argv[]) { QApplication app(argc, argv, QApplication::GuiServer); CopServ screen; // screen.setGeometry(0, 0, 240, 320); screen.show(); return app.exec(); }

//Cel.h //子程式1的標頭檔 #ifndef CEL_H #define CEL_H #include <QWidget> class QSlider; class QHBoxLayout; class Cel : public QWidget { Q_OBJECT public: Cel(); ~Cel() {}; private slots: void handleMsg(const QString &message, const QByteArray &data); void sendMsg(int celNum); //槽 private: void fahToCel(int fahNum); void createScreen(); void createCel(); void listenChannel(); QSlider* slider; QHBoxLayout* celLayout; }; //Cel.cpp #endif //CEL_H #include <QPushButton> #include <QSlider> #include <QLabel> #include <QLCDNumber> #include <QVBoxLayout> #include <QHBoxLayout> #include <QApplication> #include <QCopChannel> #include <QDataStream> #include <QByteArray> #include "Cel.h" Cel::Cel() : QWidget() { createScreen(); listenChannel(); } void Cel::createScreen() { QPushButton* quitBtn = new QPushButton("Quit"); createCel(); QVBoxLayout *mainLayout = new QVBoxLayout; mainLayout->addWidget(quitBtn); mainLayout->addLayout(celLayout); setLayout(mainLayout); slider->setFocus(); connect(quitBtn, SIGNAL(clicked()), qApp, SLOT(quit())); setWindowTitle("Celsius"); } void Cel::createCel() { slider = new QSlider(Qt::Vertical); slider->setRange(0, 100); slider->setValue(0); slider->setTickPosition(QSlider::TicksLeft); QLabel* celLabel = new QLabel("0"); celLayout = new QHBoxLayout; celLayout->addWidget(celLabel, 0, Qt::AlignRight); celLayout->addWidget(slider, 0, Qt::AlignLeft); celLayout->setSpacing(10); connect(slider, SIGNAL(valueChanged(int)), celLabel, SLOT(setNum(int))); connect(slider, SIGNAL(valueChanged(int)), this, SLOT(sendMsg(int))); } void Cel::fahToCel(int fahNum) { int celNum = (fahNum - 32) * 5 / 9; slider->setValue(celNum); } void Cel::listenChannel() { QCopChannel *channel = new QCopChannel("/System/Temperature", this);//註冊Channel connect(channel, SIGNAL(received(const QString &, const QByteArray &)), this, SLOT(handleMsg(const QString &, const QByteArray &))); } void Cel::handleMsg(const QString &message, const QByteArray &data)//處理收到資訊 { QDataStream in(data); if (message == "ConvertFahToCel(int)") { int fahNum; in >> fahNum; fahToCel(fahNum); } } void Cel::sendMsg(int celNum) //發送資訊 { QByteArray data; QDataStream out(&data, QIODevice::WriteOnly); out << celNum; QCopChannel::send("/System/Temperature", "ConvertCelToFah(int)", data); } #include <QApplication> #include "Cel.h" int main(int argc, char *argv[]) { QApplication app(argc, argv/*, QApplication::GuiClient*/); Cel screen; screen.setGeometry(0, 25, 100, 250); screen.show(); return app.exec(); }

 

//Fah.h 子程式2的標頭檔 #ifndef FAH_H #define FAH_H #include <QWidget> class QDial; class QVBoxLayout; class Fah : public QWidget { Q_OBJECT public: Fah(); ~Fah() {}; private slots: void handleMsg(const QString &message, const QByteArray &data); void sendMsg(int fahNum); //自訂槽 private: void celToFah(int celNum); void createScreen(); void createFah(); void listenChannel(); QDial* dial; QVBoxLayout* fahLayout; }; #endif //FAH_H #include <QPushButton> #include <QDial> #include <QLCDNumber> #include <QVBoxLayout> #include <QApplication> #include <QCopChannel> #include <QDataStream> #include <QByteArray> #include "Fah.h" Fah::Fah() : QWidget() { createScreen(); listenChannel(); } void Fah::createScreen() { QPushButton* quitBtn = new QPushButton("Quit"); createFah(); QVBoxLayout *mainLayout = new QVBoxLayout; mainLayout->addWidget(quitBtn); mainLayout->addLayout(fahLayout); setLayout(mainLayout); dial->setFocus(); connect(quitBtn, SIGNAL(clicked()), qApp, SLOT(quit())); setWindowTitle("Fahrenheit"); } void Fah::createFah() { QLCDNumber* lcdNum = new QLCDNumber(3); lcdNum->setSegmentStyle(QLCDNumber::Filled); lcdNum->display(32); dial = new QDial; dial->setRange(32, 212); dial->setValue(32); dial->setNotchesVisible(true); fahLayout = new QVBoxLayout; fahLayout->addWidget(lcdNum, 0, Qt::AlignBottom | Qt::AlignHCenter); fahLayout->addWidget(dial); fahLayout->setSpacing(10); connect(dial, SIGNAL(valueChanged(int)), lcdNum, SLOT(display(int))); connect(dial, SIGNAL(valueChanged(int)), this, SLOT(sendMsg(int))); } void Fah::celToFah(int celNum) { int fahNum = (celNum * 9 / 5) + 32; dial->setValue(fahNum); } void Fah::listenChannel() { QCopChannel *channel = new QCopChannel("/System/Temperature", this); connect(channel, SIGNAL(received(const QString &, const QByteArray &)), this, SLOT(handleMsg(const QString &, const QByteArray &))); } void Fah::handleMsg(const QString &message, const QByteArray &data) { QDataStream in(data); if (message == "ConvertCelToFah(int)") { int celNum; in >> celNum; celToFah(celNum); } } void Fah::sendMsg(int fahNum) { QByteArray data; QDataStream out(&data, QIODevice::WriteOnly); out << fahNum; QCopChannel::send("/System/Temperature", "ConvertFahToCel(int)", data); } #include <QApplication> #include "Fah.h" int main(int argc, char *argv[]) { QApplication app(argc, argv); Fah screen; screen.setGeometry(130, 25, 100, 250); screen.show(); return app.exec(); }