How to Output Strings in MainWindow which are generated in external .cpp file

[Lumbricus]

Hi Friends,

I have a function that does some calculations(find_other_comets.cpp) and want to update a QTextBrowser widget (in mainwindow.cpp) with text generated in that function. I press a button and my calculation is called, at some times i want to output the progress/data to the Textbrowser. If i understand right i cannot acces the main window from the outside ( find_other_comets.cpp)?! I tried using this in the external cpp:

ui->textBrowser->setText(str);

ui->textBrowser->setText(str);

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My question is what is the right approch to pass Strings to the TextBrowser in mainwindow? if additional code or information is needed im happy to supply it!

[anda_skoa]

There are a couple of options, like having access to the textBrowser for the code in that other file.

But probably the easiest way is to make the other code emit a signal with the text and the connect that signal to the setText() slot.

Cheers,
_

[Lumbricus]

thx for taking your time!

I have tried using signals and slots but got confused while trying. How exactly does one emit a signal when i haven't created an object in the external cpp file? I understand that i have to create a slot in mainwindow and a function that will be run when the slot catches a signal.

header mainwindow.h

namespace Ui {
class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private slots:
    void on_pushButton_clicked();
 
    void on_lineEdit_metakernel_editingFinished();
 
    void on_pushButton_4_clicked();
 
    void on_lineEdit_editingFinished();
 
    void print_to_browser(QString str);
 
private:
     Ui::MainWindow *ui;
};

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

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

private slots:
    void on_pushButton_clicked();

    void on_lineEdit_metakernel_editingFinished();

    void on_pushButton_4_clicked();

    void on_lineEdit_editingFinished();

    void print_to_browser(QString str);

private:
     Ui::MainWindow *ui;
};

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Function in mainwindow.ccp

void MainWindow::print_to_browser(QString str)
{
     ui->textBrowser->setText(str);
}

void MainWindow::print_to_browser(QString str)
{
     ui->textBrowser->setText(str);
}

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But i'm kinda lost on how to emit the signal or even define it if didnt creat an objectin in find_other_comets.ccp. And following that the connect statement is not clear also. Can any one give me a example?

[anda_skoa]

Well, emitting a signal does indeed require an object.
Since you gave no indication what your find_other_comets.cpp looks like I assume that you had some object in there.

If it contains just a function, then pass the pointer of the text browser to the function and call it directly.

Cheers,
_

[Lumbricus]

Thx, passing the QTextBrowser pointer to the function directly let me modify it in the function.