Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. signal and slots between two classes
Forum Updated to NodeBB v4.3 + New Features

signal and slots between two classes

Scheduled Pinned Locked Moved General and Desktop
31 Posts 5 Posters 10.0k Views 5 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • mrjjM Offline
    mrjjM Offline
    mrjj
    Lifetime Qt Champion
    wrote on last edited by mrjj
    #2

    Hi
    One thing I saw
    connect(ui->nextButtonSignin, SIGNAL(clicked()),this,SIGNAL(clickedNextSignal()));
    should have been SLOT in last.

    If possible, use the new syntax as it has more type checking

    connect( ui->nextButtonSignin, &QPushButton::clicked, this, &Dialog::clickedNextSignal);
    (If nextButtonSignin is QPushbutton)

    Hmm, there is something odd going on:
    signin has signal clickedNextSignal but you never call
    emit clickedNextSignal()
    so in Dialog::Dialog
    when you say
    connect(_signin , SIGNAL(clickedNextSignal()),this,SLOT(openBox()));
    Its correct but since signin do not emit (send) signal then nothing will happen.

    So if you add a slot to sign in, lets cal lit DoNext (bad name:)
    and hook it up to the button
    connect(ui->nextButtonSignin, SIGNAL(clicked()),this,SLOT(DoNext()));
    and in
    void DoNext() {
    emit clickedNextSignal();
    }
    Then the connect in Dialog should be more fun,
    So in short.
    NextButton clicked goes to signin slot that emit clickedNextSignal signal , that is hooked up to Dialog openBox().

    Hope it helps.

    M 1 Reply Last reply
    0
    • M Offline
      M Offline
      marlenet15
      wrote on last edited by
      #3
      This post is deleted!
      mrjjM 1 Reply Last reply
      0
      • M marlenet15

        This post is deleted!

        mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by
        #4

        @marlenet15
        Ok, as far as I know you cannot connect signal to signal but you can
        connect multiple signals to one slot.

        Did you place break point to see if the DoNext is called and
        also check in application output that none of the connets return fail.
        maybe even
        qDebug() << " result:" << connect(ui->nextButtonSignin, SIGNAL(clicked()),this,SLOT(DoNext())); for both connect to see
        if they are successful.

        JKSHJ 1 Reply Last reply
        0
        • mrjjM mrjj

          Hi
          One thing I saw
          connect(ui->nextButtonSignin, SIGNAL(clicked()),this,SIGNAL(clickedNextSignal()));
          should have been SLOT in last.

          If possible, use the new syntax as it has more type checking

          connect( ui->nextButtonSignin, &QPushButton::clicked, this, &Dialog::clickedNextSignal);
          (If nextButtonSignin is QPushbutton)

          Hmm, there is something odd going on:
          signin has signal clickedNextSignal but you never call
          emit clickedNextSignal()
          so in Dialog::Dialog
          when you say
          connect(_signin , SIGNAL(clickedNextSignal()),this,SLOT(openBox()));
          Its correct but since signin do not emit (send) signal then nothing will happen.

          So if you add a slot to sign in, lets cal lit DoNext (bad name:)
          and hook it up to the button
          connect(ui->nextButtonSignin, SIGNAL(clicked()),this,SLOT(DoNext()));
          and in
          void DoNext() {
          emit clickedNextSignal();
          }
          Then the connect in Dialog should be more fun,
          So in short.
          NextButton clicked goes to signin slot that emit clickedNextSignal signal , that is hooked up to Dialog openBox().

          Hope it helps.

          M Offline
          M Offline
          marlenet15
          wrote on last edited by
          #5

          @mrjj I read from somewhere that you can have connect with two signals. I did try your recommendation but nothing happens.

          1 Reply Last reply
          0
          • mrjjM Offline
            mrjjM Offline
            mrjj
            Lifetime Qt Champion
            wrote on last edited by mrjj
            #6

            also how does you main.cpp look like ?

            You show the Dialog instead of mainwindow?

            M 1 Reply Last reply
            0
            • mrjjM mrjj

              also how does you main.cpp look like ?

              You show the Dialog instead of mainwindow?

              M Offline
              M Offline
              marlenet15
              wrote on last edited by
              #7

              @mrjj

              #include "dialog.h"
              #include <QApplication>
              
              int main(int argc, char *argv[])
              {
                  QApplication a(argc, argv);
                  Dialog *w = new Dialog();
                  w->showNormal();
              
                  return a.exec();
              }``` 
              
              and yes I used Dialog instead of mainwindow
              mrjjM 1 Reply Last reply
              0
              • M marlenet15

                @mrjj

                #include "dialog.h"
                #include <QApplication>
                
                int main(int argc, char *argv[])
                {
                    QApplication a(argc, argv);
                    Dialog *w = new Dialog();
                    w->showNormal();
                
                    return a.exec();
                }``` 
                
                and yes I used Dialog instead of mainwindow
                mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by
                #8

                @marlenet15 said:
                Hi I think the dialog in dialog mess up something.
                Didnt work for me if I new the sign dialog in Start dialog constructor.
                But it does work if I hooked it up outside.
                Have a look at this example
                https://www.dropbox.com/s/bvpps7qd8oovtjf/gonext.zip?dl=0
                Its the same idea but created slightly different.

                M 1 Reply Last reply
                0
                • mrjjM mrjj

                  @marlenet15 said:
                  Hi I think the dialog in dialog mess up something.
                  Didnt work for me if I new the sign dialog in Start dialog constructor.
                  But it does work if I hooked it up outside.
                  Have a look at this example
                  https://www.dropbox.com/s/bvpps7qd8oovtjf/gonext.zip?dl=0
                  Its the same idea but created slightly different.

                  M Offline
                  M Offline
                  marlenet15
                  wrote on last edited by
                  #9

                  @mrjj I followed your example but it is still not working.

                  mrjjM 1 Reply Last reply
                  0
                  • M marlenet15

                    @mrjj I followed your example but it is still not working.

                    mrjjM Offline
                    mrjjM Offline
                    mrjj
                    Lifetime Qt Champion
                    wrote on last edited by
                    #10

                    @marlenet15
                    ??
                    so the getnext example which runs here do no work when you compile it?

                    M 1 Reply Last reply
                    0
                    • mrjjM mrjj

                      @marlenet15
                      ??
                      so the getnext example which runs here do no work when you compile it?

                      M Offline
                      M Offline
                      marlenet15
                      wrote on last edited by
                      #11

                      @mrjj ok it works. I redid my code using only QWidgets and it works. I think I know the problem and I forgot to mention it. I made QDialog a stacked widget and promoted the file signin.

                      1 Reply Last reply
                      0
                      • mrjjM mrjj

                        @marlenet15
                        Ok, as far as I know you cannot connect signal to signal but you can
                        connect multiple signals to one slot.

                        Did you place break point to see if the DoNext is called and
                        also check in application output that none of the connets return fail.
                        maybe even
                        qDebug() << " result:" << connect(ui->nextButtonSignin, SIGNAL(clicked()),this,SLOT(DoNext())); for both connect to see
                        if they are successful.

                        JKSHJ Offline
                        JKSHJ Offline
                        JKSH
                        Moderators
                        wrote on last edited by JKSH
                        #12

                        @mrjj said:

                        Ok, as far as I know you cannot connect signal to signal

                        You can. See the documentation:

                        You can connect as many signals as you want to a single slot, and a signal can be connected to as many slots as you need. It is even possible to connect a signal directly to another signal. (This will emit the second signal immediately whenever the first is emitted.)

                        Qt Doc Search for browsers: forum.qt.io/topic/35616/web-browser-extension-for-improved-doc-searches

                        mrjjM 1 Reply Last reply
                        1
                        • JKSHJ JKSH

                          @mrjj said:

                          Ok, as far as I know you cannot connect signal to signal

                          You can. See the documentation:

                          You can connect as many signals as you want to a single slot, and a signal can be connected to as many slots as you need. It is even possible to connect a signal directly to another signal. (This will emit the second signal immediately whenever the first is emitted.)

                          mrjjM Offline
                          mrjjM Offline
                          mrjj
                          Lifetime Qt Champion
                          wrote on last edited by
                          #13

                          @JKSH
                          Aha, that is news for me. so that is like a chain signal or almost like an alias.

                          @marlenet15
                          Super. not sure what the real reason was but as long as it works :)

                          M 1 Reply Last reply
                          0
                          • mrjjM mrjj

                            @JKSH
                            Aha, that is news for me. so that is like a chain signal or almost like an alias.

                            @marlenet15
                            Super. not sure what the real reason was but as long as it works :)

                            M Offline
                            M Offline
                            marlenet15
                            wrote on last edited by
                            #14

                            @mrjj Before creating the stackedwidget it worked. After adding it, it doesn't work anymore.

                            mrjjM 1 Reply Last reply
                            0
                            • M marlenet15

                              @mrjj Before creating the stackedwidget it worked. After adding it, it doesn't work anymore.

                              mrjjM Offline
                              mrjjM Offline
                              mrjj
                              Lifetime Qt Champion
                              wrote on last edited by
                              #15

                              @marlenet15
                              Ok. do you promote a qDialog to a stackwidget ?
                              Not sure I fully understand.
                              At least I have never tried that.

                              M 1 Reply Last reply
                              0
                              • mrjjM mrjj

                                @marlenet15
                                Ok. do you promote a qDialog to a stackwidget ?
                                Not sure I fully understand.
                                At least I have never tried that.

                                M Offline
                                M Offline
                                marlenet15
                                wrote on last edited by
                                #16

                                @mrjj on the .ui file of the class dialog, I created a stackedwidget and promoted the file signin.h

                                mrjjM 1 Reply Last reply
                                0
                                • M marlenet15

                                  @mrjj on the .ui file of the class dialog, I created a stackedwidget and promoted the file signin.h

                                  mrjjM Offline
                                  mrjjM Offline
                                  mrjj
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #17

                                  @marlenet15
                                  so the signin dialog was sort of inline to Dialog ?

                                  M 1 Reply Last reply
                                  0
                                  • mrjjM mrjj

                                    @marlenet15
                                    so the signin dialog was sort of inline to Dialog ?

                                    M Offline
                                    M Offline
                                    marlenet15
                                    wrote on last edited by
                                    #18

                                    @mrjj can you exaplain what you mean by that? Sorry

                                    mrjjM 1 Reply Last reply
                                    0
                                    • M marlenet15

                                      @mrjj can you exaplain what you mean by that? Sorry

                                      mrjjM Offline
                                      mrjjM Offline
                                      mrjj
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #19

                                      @marlenet15
                                      Hi np.
                                      Im not 100% sure what you did.
                                      If you promote a widget to a dialog.
                                      the dialog will be sort of inside the parent/widget that contains the
                                      promoted widget.
                                      So I wondered if you promoted a stacked widget to the signin dialog ?

                                      M 1 Reply Last reply
                                      0
                                      • mrjjM mrjj

                                        @marlenet15
                                        Hi np.
                                        Im not 100% sure what you did.
                                        If you promote a widget to a dialog.
                                        the dialog will be sort of inside the parent/widget that contains the
                                        promoted widget.
                                        So I wondered if you promoted a stacked widget to the signin dialog ?

                                        M Offline
                                        M Offline
                                        marlenet15
                                        wrote on last edited by
                                        #20

                                        @mrjj I created a stackedwidget in dialog.ui, in there I promoted signin.h into the stackedwidget.

                                        JKSHJ 1 Reply Last reply
                                        0
                                        • mrjjM Offline
                                          mrjjM Offline
                                          mrjj
                                          Lifetime Qt Champion
                                          wrote on last edited by mrjj
                                          #21

                                          ahh that way. Hmm should be the same as using a plain qwidget but seems it was not.

                                          Can I ask what kind of design u are after ?
                                          like sort of custom wizard style thing ?

                                          M 1 Reply Last reply
                                          0

                                          • Login

                                          • Login or register to search.
                                          • First post
                                            Last post
                                          0
                                          • Categories
                                          • Recent
                                          • Tags
                                          • Popular
                                          • Users
                                          • Groups
                                          • Search
                                          • Get Qt Extensions
                                          • Unsolved