signal slot conection using a string, not a SLOT

[rianquinn]

Ok here is my problem. I have to connect a QAction signal to a QTextEdit slot. Here are my parameters

connect
object *
SIGNAL (triggered ())
object *
QString (containing slot name) -- Eample: signal is void copy (), string is "copy"

How can I do this. Currently all of my attenpts have failed. I always get a false returned from the connect function.

On thing I know is this should be possible because the slots can be found via QMetaObject::invokeMethod using a string.

[wysota]

Hmm... doesn't SLOT(somestring) work? If it doesn't (and it probably doesn't), then take a look at Qt source code and find how the SLOT macro expands and modify the string to be the same.

[rianquinn]

Where can I find this macro definition. I have looked all over the source code and can't find this definition.

[wysota]

src/corelib/kernel/qobjectdefs.h:

#define SLOT(a)          "1"#a
#define SIGNAL(a)        "2"#a

#define SLOT(a)          "1"#a
#define SIGNAL(a)        "2"#a

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So in your case, just prepend the slot signature with "1".

[rianquinn]

WOW... it works great.

I had to adjust my string to be "1copy ()" instead of "copy", and it works. I wonder why they add the 1 to the end of this? Seems this makes things a bit more difficult. I'm there is a reason.

[wysota]

It's an easy way to distinguish between methods ("0"), slots ("1"), signals ("2") and garbage (??).

[Codepoet]

They prepend a digit because in C++ no identifiers like method or variable names may start with a digit. That way you can distinguish between the types like wysota mentioned.