内容

• 公共函数
• 信号
• 静态公共成员
• 详细描述

QCopChannel Class

The QCopChannel class provides communication capabilities between clients in Qt for Embedded Linux . 更多...

头：	#include <QCopChannel>
继承：	QObject

• 所有成员列表，包括继承成员
• 兼容成员

公共函数

	QCopChannel (const QString & channel , QObject * parent = 0)
virtual	~QCopChannel ()
QString	channel () const
virtual void	receive (const QString & message , const QByteArray & data )

• 29 公共函数继承自 QObject

信号

void	received (const QString & message , const QByteArray & data )

• 1 信号继承自 QObject

静态公共成员

bool	flush ()
bool	isRegistered (const QString & channel )
bool	send (const QString & channel , const QString & message , const QByteArray & data )
bool	send (const QString & channel , const QString & message )

• 7 静态公共成员继承自 QObject

额外继承成员

• 1 特性继承自 QObject
• 1 公共槽继承自 QObject
• 8 保护函数继承自 QObject

详细描述

The QCopChannel class provides communication capabilities between clients in Qt for Embedded Linux .

注意，此类只可用于 Qt for Embedded Linux .

The Qt COmmunication Protocol (QCOP) is a many-to-many protocol for transferring messages across registered channels. A channel is registered by name, and anyone who wants to can listen to the channel as well as send messages through it. The QCOP protocol allows clients to communicate both within the same address space and between different processes.

To send messages to a given channel, QCopChannel provides the static send () function. Using this function alone, the messages are queued until Qt re-enters the event loop. To immediately flush all queued messages to the registered listeners, call the static flush () 函数。

To listen to the traffic on a given channel, you typically instantiate a QCopChannel object for the given channel and connect to its received () signal that is emitted whenever there is incoming data. Use the static isRegistered () function to query the server for the existence of a given channel. QCopChannel 提供 channel () function returning the name of this QCopChannel object's channel.

In additon, QCopChannel provides the virtual receive () function that can be reimplemented to filter the incoming messages and data. The default implementation simply emits the received () 信号。

另请参阅 QWSServer , QWSClient ，和 Qt for Embedded Linux 体系结构 .

成员函数文档编制

QCopChannel:: QCopChannel (const QString & channel , QObject * parent = 0)

构造 QCopChannel object for the specified channel ，采用给定 parent . Once created, the channel is registered by the server.

另请参阅 isRegistered () 和 channel ().

[虚拟] QCopChannel:: ~QCopChannel ()

销毁此 QCopChannel 对象。

The server is notified that this particular listener has closed its connection. The server will keep the channel open until the last registered listener detaches.

另请参阅 isRegistered () 和 channel ().

QString QCopChannel:: channel () const

Returns the name of this object's channel.

另请参阅 isRegistered ().

[static] bool QCopChannel:: flush ()

Flushes all queued messages to the registered listeners.

Note that this function returns false if no QApplication has been constructed, otherwise it returns true.

该函数在 Qt 4.2 引入。

另请参阅 send ().

[static] bool QCopChannel:: isRegistered (const QString & channel )

Queries the server for the existence of the given channel . Returns true if the channel is registered; otherwise returns false.

另请参阅 channel () 和 send ().

[虚拟] void QCopChannel:: receive (const QString & message , const QByteArray & data )

Processes the incoming message and data .

This function is called by the server when this object's channel receives new messages. Note that the default implementation simply emits the received () signal; reimplement this function to process the incoming message and data .

Note that the format of the given data has to be well defined in order to extract the information it contains. In addition, it is recommended to use the DCOP convention. This is not a requirement, but you must ensure that the sender and receiver agree on the argument types. For example:

void MyClass::receive(const QString &message, const QByteArray &data)
{
    QDataStream in(data);
    if (message == "execute(QString,QString)") {
        QString cmd;
        QString arg;
        in >> cmd >> arg;
        ...
    } else if (message == "delete(QString)") {
        QString fileName;
        in >> fileName;
        ...
    } else {
        ...
    }
}
					

The above code assumes that the message is a DCOP-style function signature and the data contains the function's arguments.

另请参阅 send (), channel ()，和 received ().

[signal] void QCopChannel:: received (const QString & message , const QByteArray & data )

This signal is emitted whenever this object's channel receives new messages (i.e., it is emitted by the receive () function), passing the incoming message and data 作为参数。

另请参阅 receive () 和 channel ().

[static] bool QCopChannel:: send (const QString & channel , const QString & message , const QByteArray & data )

发送给定 message on the specified channel 采用给定 data . The message will be distributed to all clients subscribed to the channel. Returns true if the message is sent successfully; otherwise returns false.

It is recommended to use the DCOP convention. This is not a requirement, but you must ensure that the sender and receiver agree on the argument types.

注意， QDataStream provides a convenient way to fill the byte array with auxiliary data. For example:

QByteArray data;
QDataStream out(&data, QIODevice::WriteOnly);
out << QString("cat") << QString("file.txt");
QCopChannel::send("System/Shell", "execute(QString,QString)", data);
					

In the code above the channel is "System/Shell" 。 message is an arbitrary string, but in the example we've used the DCOP convention of passing a function signature. Such a signature is formatted as "functionname(types)" where 类型 is a list of zero or more comma-separated type names, with no whitespace, no consts and no pointer or reference marks, i.e. no "*" or "&".

另请参阅 receive () 和 isRegistered ().

[static] bool QCopChannel:: send (const QString & channel , const QString & message )

这是重载函数。