如何獲得一個類的變量成員的值到另一個類

Question

一個類有一個組合框，用戶必須從中選擇一個數字。然後該值被分配給一個變量，並且由於組合框項目是文本，所以用戶選擇的變量保存數字（換句話說，文本）使用'toInt（）'轉換爲整數值，並分配給同班。現在，不同的類必須能夠訪問另一個類的整數變量（即用戶選擇的數字），以便根據它的值向用戶顯示相同數量的小部件。當我從組合框中選擇數字並按下按鈕時，沒有任何顯示。我希望從組合框中選擇相同的數字以作爲行編輯進行dsiplay。

該代碼;

combobox.h

#ifndef COMBOBOX_H 
#define COMBOBOX_H 

#include <QDialog> 
#include <QComboBox> 
#include <QPushButton> 
#include <QStringList> 
#include <QVBoxLayout> 

class ComboBox : public QDialog { 
public: 
    ComboBox(); 
    ~ComboBox(); 

private slots: 
    void on_go_button_clicked(); 

private: 
    QComboBox *comboBox; 

public: 
    QPushButton *go; 
    int textToInt; 
}; 

#endif // COMBOBOX_H 

lineeditwidgets.h

#ifndef LINEEDITWIDGETS_H 
#define LINEEDITWIDGETS_H 

#include <QDialog> 
#include <QLineEdit> 
#include <QVBoxLayout> 
#include "combobox.h" 

class LineEditWidgets : public QDialog { 
public: 
    LineEditWidgets(); 
    LineEditWidgets(ComboBox*);  //edited 
    ~LineEditWidgets(); 

private: 
    QLineEdit *lineEdit; 

    //object created so member of class 'ComboBox' can be accessed 
    ComboBox *take; 
}; 

#endif // LINEEDITWIDGETS_H 

mainwindow.h

#ifndef MAINWINDOW_H 
#define MAINWINDOW_H 

#include <QMainWindow> 
#include <QStackedWidget> 

#include "lineeditwidgets.h" 
#include "combobox.h" 

class MainWindow : public QMainWindow { 
    Q_OBJECT 

public: 
    explicit MainWindow(QWidget *parent = 0); 
    ~MainWindow(); 

private slots: 
    void go_button_clicked(); 

private: 
    QStackedWidget *pages; 

    ComboBox *comboBoxWindow; 
    LineEditWidgets *lineEditWindow; 

}; 

#endif // MAINWINDOW_H 

combobox.cpp

#include <QtGui> 
#include "combobox.h" 

ComboBox::ComboBox() { 
    comboBox = new QComboBox; 
    QStringList items; 
    items << "1" << "2" << "3" << "4" << "5"; 
    comboBox->addItems(items); 

    go = new QPushButton("Go"); 

    QVBoxLayout *layout = new QVBoxLayout; 
    layout->addWidget(comboBox); 
    layout->addWidget(go); 

    setLayout(layout); 

    /*i get 'No such slot QDialog::on_go_button_clicked()' even though this 
     function was declared as a slot in the header file*/ 
    connect(go, SIGNAL(clicked()), this, SLOT(on_go_button_clicked())); 
} 

/*the number selected from combobox is converted to integer here. I can't 
    seem to understand how 'toInt()' works, i thought it was like 
    'stringstream()' */ 
void ComboBox::on_go_button_clicked() { 
    QString text; 
    comboBox->currentTextChanged(text); 
    QString getCurrentText = comboBox->currentText(); 
    textToInt = getCurrentText.toInt(); 
} 

ComboBox::~ComboBox() { 

} 

lineeditwidgets.cpp

#include <QtGui> 
#include "lineeditwidgets.h" 

LineEditWidgets::LineEditWidgets(ComboBox* comboBoxWin) { //edited 
    /*member of 'ComboBox' class is accessed here and assigned to int 
     variable. I thought it's supposed to be holding the number the user 
     selected by now*/   
    /*take = new ComboBox;*/   //edited 
     take = comboBoxWin;    //edited 

    int numb = take->textToInt; 

    QVBoxLayout *layout = new QVBoxLayout; 

    for (int i = 0; i < numb; i++) { 
     lineEdit = new QLineEdit; 
     layout->addWidget(lineEdit); 
    } 

    setLayout(layout); 
} 

LineEditWidgets::~LineEditWidgets(){ 

} 

mainwindow.cpp

#include "mainwindow.h" 
#include <ui_mainwindow.h> 

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent){ 
    comboBoxWindow = new ComboBox; 
    /*lineEditWindow = new LineEditWidgets;*/  //edited 
    lineEditWindow = new LineEditWidgets(comboBoxWindow); //edited 

    pages = new QStackedWidget; 
    pages->insertWidget(1, comboBoxWindow); 
    pages->insertWidget(2, lineEditWindow); 
    pages->setCurrentWidget(comboBoxWindow); 

    setCentralWidget(pages); 

    connect(comboBoxWindow->go, SIGNAL(clicked()), this, 
    SLOT(go_button_clicked())); 
} 

void MainWindow::go_button_clicked() { 
    pages->setCurrentWidget(lineEditWindow); 
} 

MainWindow::~MainWindow() { 

} 

的main.cpp

#include "mainwindow.h" 
#include <QApplication> 

int main(int argc, char *argv[]) { 
    QApplication a(argc, argv); 

    MainWindow w; 
    w.show(); 

    return a.exec(); 
} 

Answer 1

我認爲這個問題是存在的ComboBox兩個單獨的實例。一個是在主窗口中創建 - comboBoxWindow = new ComboBox;並創建另一個在LineEditWidgets - take = new ComboBox;

你應該考慮通過ComboBox實例 - comboBoxWindow到LineEditWidgets實例lineEditWindow在MainWindow構造和lineEditWindow必須的ComboBox傳遞的實例保存到ComboBox指針 - take。