QDBusPendingCallWatcher Class

The QDBusPendingCallWatcher class provides a convenient way for waiting for asynchronous replies. More...

Header: #include <QDBusPendingCallWatcher>
qmake: QT += dbus
Since: Qt 4.5
Inherits: QObject and QDBusPendingCall

This class was introduced in Qt 4.5.

Public Functions

QDBusPendingCallWatcher(const QDBusPendingCall &call, QObject *parent = nullptr)
virtual ~QDBusPendingCallWatcher()
typedef QObjectList

Macros

Additional Inherited Members

Detailed Description

The QDBusPendingCallWatcher provides the finished() signal that will be emitted when a reply arrives.

It is usually used like the following example:


      QDBusPendingCall async = iface->asyncCall("RemoteMethod", value1, value2);
      QDBusPendingCallWatcher *watcher = new QDBusPendingCallWatcher(async, this);

      QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)),
                       this, SLOT(callFinishedSlot(QDBusPendingCallWatcher*)));

Note that it is not necessary to keep the original QDBusPendingCall object around since QDBusPendingCallWatcher inherits from that class too.

The slot connected to by the above code could be something similar to the following:


  void MyClass::callFinishedSlot(QDBusPendingCallWatcher *call)
  {
      QDBusPendingReply<QString, QByteArray> reply = *call;
      if (reply.isError()) {
          showError();
      } else {
          QString text = reply.argumentAt<0>();
          QByteArray data = reply.argumentAt<1>();
          showReply(text, data);
      }
      call->deleteLater();
  }

Note the use of QDBusPendingReply to validate the argument types in the reply. If the reply did not contain exactly two arguments (one string and one QByteArray), QDBusPendingReply::isError() will return true.

See also QDBusPendingReply and QDBusAbstractInterface::asyncCall().

Member Function Documentation

QDBusPendingCallWatcher::QDBusPendingCallWatcher(const QDBusPendingCall &call, QObject *parent = nullptr)

Creates a QDBusPendingCallWatcher object to watch for replies on the asynchronous pending call call and sets this object's parent to parent.

[virtual] QDBusPendingCallWatcher::~QDBusPendingCallWatcher()

Destroys this object. If this QDBusPendingCallWatcher object was the last reference to the unfinished pending call, the call will be canceled.