How to pass the parameters between the SIGNAL and SLOTS

[mrjj]

Hi
Do you have Q_OBJECT in both classes ?

Check if the connect returns true

qDebug() << "mysignal:" << connect(&get,SIGNAL(newtextChanged_1(QString)),this,SLOT(encore_2(QString)));

[Alex42]

@mrjj thank you for your response, ,, yes i have the Q_object in the bothe classes
But When i try to test this code i have an error " no matching member function for call to "connect "

[mrjj]

@Alex42
Hi
But is the
connect function not inside a class function?

If not call it like

QObject::connect( ....

and you cannot use "this" but must use a pointer to the instance.

connect(&get,SIGNAL(newtextChanged_1(QString)),this,SLOT(encore_2(QString)));

If its not inside class, there is no this.

So please show the code around the connect.

[Alex42]

@Alex42 said in How to pass the parameters between the SIGNAL and SLOTS:

no matching member function for call to "connect "
ok , ok , I Made a Mistake
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[Alex42]

so i think the probleme is not around the connecte , becouse WITHE THE qlcdNumber work will , but withe the QLineEdit It does not work

[Alex42]

for more information , i created the principle interface (MainWindow), and in this interface i have two QPushbutton ,the first button open the firste interface (Mesure) , and the second Button open the seconde interface

• i don't get any messages about the connect failing
  -( i can to change the data between the firste interface (Mesure) and the seconde interface (Mesureone ), but with the QLineEdit i can't to transmite data between this interfaces
• i used the debugger , and the slot is called and the connect executed . But i can't to interact between this interfaces with the QLineEdit (incredible)

[mrjj]

@Alex42

Hi
Your connect seems to be called many times.
Normally you should only call it once as it will send multiple times if you connect multiple times and
that is normally not what you want.

Anyway,

Are you saying that

void Mesure :: calculate_3 ()
{

    S++;

    if (S>0)
    {
    emit newtextChanged_1(QString::number (ui->lcdNumber_1->value()));  /// works
    but  
    emit newtextChanged_1(mence->text()); // wont work ?

[Alex42]

@mrjj said in How to pass the parameters between the SIGNAL and SLOTS:

Your connect seems to be called many times.

there is no probleme if you call it many time or you call it once , i tried many situation ( call it once , and call it many time ) but that not work

[Alex42]

@mrjj said in How to pass the parameters between the SIGNAL and SLOTS:

emit newtextChanged_1(mence->text()); // wont work ?

emit newtextChanged_1(mence->text()); // wont work ? exactly what i whant to do buthe d'ont work

[mrjj]

@Alex42

Hi
does
QString test("hello");
emit newtextChanged_1(test);

works ?

Both should work if the
QString::number (ui->lcdNumber_1->value()) works.

[Alex42]

@mrjj , QString test("hello");
emit newtextChanged_1(test);

works ?

yes it works very well

[Alex42]

are you undestad that may QLineEdite change every 1000ms ?

[mrjj]

@Alex42

Ok that is a bit o.O

so try

QString text = mence->text();
qDebug() << "sending:" << text;
emit ewtextChanged_1(text);

and see if the mence is the one you think it is as that is my only guess then as
the signal clearly works :)

Yes, I understand you change the text of the lineEdit every sec,but that should not matter
as we just get what ever was set last when we ask.

[Alex42]

yes exactly what i want , befor i tried this and works very well ,
but the probleme is in the second interface i can't receve this data 
( in the seconde interface i receve only 0( the fiste values) , i can't receive the values when is chenged

[mrjj]

@Alex42

So in interface 2, you only see the "0" and never "12222" etc ?

But you could send "hello" and other string ?
That I cant explain. seems impossible.

Just so I understand.

You have a main window and 2 buttons. Each button opens a new Form/window and
form1 has a timer or something that makes a lineEdit count/set some value.
This value you try to emit to form2 when calculate_3 is called ?

[Alex42]

@mrjj said in How to pass the parameters between the SIGNAL and SLOTS:

So in interface 2, you only see the "0" and never "12222" etc ?

So in interface 2, you only see the "0" and never "12222" etc ? yes exactly
But you could send "hello" and other string ? yes i can send hello
You have a main window and 2 buttons. Each button opens a new Form/window and
form1 has a timer or something that makes a lineEdit count/set some value.
This value you try to emit to form2 when calculate_3 is called ? exactly what i want to do

[mrjj]

@Alex42
Ok. how is the LineEdit updated ?
a Qtimer ?

[Alex42]

yes a Qtimer

[mrjj]

@Alex42

Ok. hang on for 20 mins. Ill try myself as it does seem strange :)

[Alex42]

@mrjj said in How to pass the parameters between the SIGNAL and SLOTS:

Ok. hang on for 20 mins. Ill try myself as it does seem strange :)

ok thank you very match for your helpe