c++ - Emit Signal Only When QCheckBox is Checked -

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i creating set of qcheckbox dynamically based on user input so:

qwidget *wid = new qwidget(); qvboxlayout *layout = new qvboxlayout(); for(int i=0; i<numbermodes; i++) {     int k = amplitudes(i,0);     int m = amplitudes(i,1);      qstring ks = qstring::number(k);     qstring ms = qstring::number(m);     qstring position = qstring::number(i);     qstring mode = "a"+ks+ms;      qcheckbox *check = new qcheckbox(mode);     connect(check, signal(toggled(bool)), &mapper, slot(map()));     connect(check, signal(toggled(bool)), &selectmodes, slot(map()));      mapper.setmapping(check,position);     selectmodes.setmapping(check,mode);     layout->addwidget(check);     updategeometry(); }   wid->setlayout(layout); ui->scrollarea->setwidget(wid);

the qsignalmapper connected class performs calculations:

connect(&selectmodes, signal(mapped(qstring)), this, signal(checkboxclicked2(qstring))); connect(this, signal(checkboxclicked2(qstring)), &supress2, slot(listenselectedmodes(qstring))); connect(&mapper, signal(mapped(qstring)), this, signal(checkboxclicked(qstring))); connect(this, signal(checkboxclicked(qstring)), &suppress, slot(listenselectedmodes(qstring)));

what need classes receive signals when qcheckbox checked; meaning if check once, , un-check no signal should emitted, or received. not sure best approach is. ideas?

the suggestions given user2672165 excellent!

if want monitor check event not uncheck event, 1 way subclass qcheckbox widget emits particular signal when checkbox checked (e.g. checkboxchecked)

then connect signal mapper custom signal checkboxchecked, instead of standard toggle(bool) signal.

in way slot associated signal mapper invoked when checkbox checked , not when unchecked.

here simple example

#include <qapplication> #include <qtgui> #include <qvboxlayout> #include <qsignalmapper> #include <qcheckbox> #include <qdebug>  class checkablecheckbox : public qcheckbox {     q_object  public:     checkablecheckbox(const qstring &text, qwidget *parent = 0)         : qcheckbox(text, parent)     {         connect(this, signal(toggled(bool)),             this, slot(verifycheck(bool)));     }  signals:     void checkboxchecked();  public slots:     void verifycheck(bool checked) {         if (checked)             emit checkboxchecked();     } };  class test : public qwidget {     q_object public:     test(qwidget *parent = 0) : qwidget(parent) {         qsignalmapper *mapper = new qsignalmapper();          qvboxlayout *layout = new qvboxlayout();         (int = 0; < 10; i++) {             qstring mode = "a" + qstring::number(i);             checkablecheckbox *check = new checkablecheckbox(mode);             connect(check, signal(checkboxchecked()),                 mapper, slot(map()));              mapper->setmapping(check, qstring::number(i));             layout->addwidget(check);             setlayout(layout);         }         connect(mapper, signal(mapped(qstring)),             this, slot(checkboxclicked(qstring)));     }  public slots:     void checkboxclicked(const qstring &mapping) {         qwarning() << "checkbox:" << mapping << " checked";     } };  int main(int argc, char *argv[]) {     qapplication a(argc, argv);      test *wid = new test();     wid->show();      return a.exec(); }  #include "main.moc"

edit:

if want monitor change in check status , notify other portions of code status of checkbox (which want) can this... don't need qsignalmapper...

i have implemented test method testmonitorcheckstatus show mean. note need typedef qlist<bool> checkboxstatuslist; (at least far know) use qlist argument slots , signals.

edit #2: number of checkboxes set @ object creation

hope helps

#include <qapplication> #include <qtgui> #include <qvboxlayout> #include <qsignalmapper> #include <qcheckbox> #include <qlist> #include <qdebug>  typedef qlist<bool> checkboxstatuslist;  class test : public qwidget {     q_object public:     test(int totalcheckboxes, qwidget *parent = 0) : qwidget(parent)     {         qvboxlayout *layout = new qvboxlayout();         (int = 0; < totalcheckboxes; i++) {             qstring mode = "a" + qstring::number(i);             qcheckbox *checkbox = new qcheckbox(mode);             connect(checkbox, signal(toggled(bool)),                 this, slot(monitorcheckstatus()));             m_checkboxlist.append(checkbox);             layout->addwidget(checkbox);         }         setlayout(layout);          connect(this, signal(checkboxstatuschanged(checkboxstatuslist)),             this, slot(testmonitorcheckstatus(checkboxstatuslist)));     }  public slots:     void monitorcheckstatus() {         checkboxstatuslist checkboxstatus;         (int = 0; < m_checkboxlist.count(); ++i)             checkboxstatus.append(m_checkboxlist.at(i)->ischecked());         emit checkboxstatuschanged(checkboxstatus);     }      void testmonitorcheckstatus(const checkboxstatuslist &checkboxstatus) {         (int = 0; < checkboxstatus.count(); ++i)             qwarning() << "checkbox:" << << " is" << (checkboxstatus.at(i) ? "checked" : "unchecked");         qwarning(" ");     }  signals:     void checkboxstatuschanged(const checkboxstatuslist &checkboxstatus);  private:     qlist<qcheckbox *> m_checkboxlist; };  int main(int argc, char *argv[]) {     qapplication a(argc, argv);      test *wid = new test(10);     wid->show();      return a.exec(); }  #include "main.moc"

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