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using UI with signals and elements



  • hi I've been studying qt recently and i know how to use signals in fact the problem I am facing right now I've already wrote it in cpp,

    #include <QApplication>
    #include <QLineEdit>
    #include <QWidget>
    #include <QLabel>
    #include <QVBoxLayout>
    
    int main(int argc, char *argv[])
    {
      QApplication a(argc, argv);
    
      QWidget widget;
      QLineEdit *lineEdit = new QLineEdit;
      QLabel *label = new QLabel;
    
      QVBoxLayout *layout = new QVBoxLayout;
      layout->addWidget(lineEdit);
      layout->addWidget(label);
      widget.setLayout(layout);
    
      QObject::connect(
            lineEdit, SIGNAL(textChanged(const QString&)),
            label, SLOT(setText(const QString&)) );
    
      widget.show();
    
      return a.exec();
    }
    
    

    so I'm trying to write the same program using ui so I create the same ui and right click on line edit go to slots and choose ontextchanged and it gives me this:

    #include "mainwindow.hpp"
    #include "ui_mainwindow.h"
    
    MainWindow::MainWindow(QWidget *parent)
      : QMainWindow(parent)
      , ui(new Ui::MainWindow)
    {
      ui->setupUi(this);
    }
    
    MainWindow::~MainWindow()
    {
      delete ui;
    }
    
    
    void MainWindow::on_lineEdit_textChanged(const QString &arg1)
    {
    
    }
    
    

    i don't know what to do next. how do i connect a ui element 's signal to another slot? what should i write in this case inside the

    void MainWindow::on_lineEdit_textChanged(const QString &arg1)
    {
    
    }
    

    method?


  • Lifetime Qt Champion

    @nullbuil7 said in using UI with signals and elements:

    what should i write in this case inside the

    ui->label->setText(arg1);
    

    I guess? Or what is the question?



  • I found the answer here:
    https://doc.qt.io/archives/qt-4.8/designer-connection-mode.html
    It's from Qt 4.8 but still unchanged.


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