How to call a function from one class into another(main) class in Qt Creator?

SHUBHAM SINGH RAO

Present State: I have designed a keypad GUI in qt creator by making a separate class and i have displayed the entered text locally in that GUI. But I need to merge this keypad with my main GUI.

I have implemented'friend function concept' to achieve the task. But I m facing some errors in this

I m attaching the code along with the question:

keypad class file :

kp16.h

namespace Ui {
class kp16;
}

class MainWindow;

class kp16 :
public QWidget
{
Q_OBJECT

public:
explicit kp16(QWidget *parent = 0);

~kp16();
QString dat;
void handles();

private:
Ui::kp16 *ui;

friend class Mainwindow ; / /Now mainwindow class can access private members of kp16
friend int MainWindow::inputdata( ); ERROR COMING / / Inputdata() function of mainwindow can access internal members of kp16

};
#endif //KP16_H

mainwindow.h

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
int inputdata( kp16 val ); ERROR COMING //declare inputdata function in mainwindow
int i=0;

~MainWindow();
public slots:

kp16.cpp

kp16::kp16(QWidget *parent) :
QWidget(parent),
ui(new Ui::kp16)
{
ui->setupUi(this);
connect(ui->k_pushButton_2,SIGNAL(clicked()),this,SLOT(handles()));
}

kp16::~kp16()
{
delete ui;
}

void kp16::handles()
{
QPushButton* button = (QPushButton*)(sender());
QString fd=button->text();
dat.append(fd);
ui->label->setText(dat);
}

mainwindow.cpp

kp16 *kp; //creating instance of kp16

int inputdata( kp16 val) // friend function definition
{
QString movedata=0;
movedata=val.dat;
return movedata.toInt();
}

void MainWindow::on_lineEdit_textEdited(const QString &arg1)
{
QString displayKeypad;
displayKeypad= inputdata(*kp);

ui->lineEdit->setText(displayKeypad);
}

ERRORS:

1. error: prototype for 'friend int MainWindow::inputdata()'
does not match any in class 'MainWindow'
[in kp16.h]
2.error: candidate is: int MainWindow::inputdata(kp16) [In mainwindow.h]

mrjj

Hi
Why do you need a friend function ?
To get data from kp16 you can just let it emit a signal and connect that to s slot in
mainwindow to get what ever its sending.

ethanscott

Exactly. There is no use of the friend function over here