Qt signal adapter library

[mwilson]

I have released QtSignalAdapters to https://sourceforge.net/projects/qtsignaladapter/.

While not directly related to Ice, it seems that a lot of Ice fans use Qt, so I thought it might prove useful to some of you.

QtSignalAdapters makes it easy to connect a Qt signal to class methods, stand-alone functions, and function objects. The library is header only, and depends on Boost (www.boost.org).

An example will help explain what QtSignalAdapters is for. Let's say we have a slice file:

module Motors
{
   interface MotorControl
   {
        void setMotorMoveCounts(int motorCounts);
        void move();
   };
};

We can connect a QtPushButton directly to the move method, and a QSpinBox directory to the setMotorMoveCounts method, of a MotorControlPrx:

connect0<void()>(pushButton, SIGNAL(clicked()),
   boost::bind(&IceProxy::Motors::MotorControl::move, motorControlPrx_.get());

connect1<void(int)>(spinBox, SIGNAL(valueChanged(int)),
    boost::bind(&IceProxy::Motors::MotorControl::setMotorMoveCounts, motorControlPrx_.get(), _1));

The library provides connect methods for zero to five parameters, and the parameters can be any types. See the TestQt2Func subdirectory for another example. The adapters that are created by the connectX methods are made children of the QObject (pushButton, spinBox), so that when those objects are deleted, the adapter is also deleted.

[mwilson]

That should have been "a QSpinBox directly" after the first code block.

In the example, the "motorControlPrx_.get()" returns a raw pointer to the proxy. This does not increase the reference count of the smart pointer proxy object. This shouldn't be a problem as long as some entity holds the proxy object and the proxy doesn't change. If you want boost::bind to hold a reference to the proxy, check out the posting:

boost::shared_ptr

So for the MotorControl example, you would add this snippet somewhere (this would be very easy for slice2cpp to generate):

namespace IceProxy
{
namespace Motors
{
    template<class T> inline T* get_pointer(
        IceInternal::ProxyHandle<T> const & p)
    {
        return p.get();
    }
}
}

Boost::bind is written to handle boost::shared_ptr specifically, but defining this function template allows the IceUtil smart pointer to be held by boost::bind....