passing varying qstring value to QDialog from MAINWINDOW

Hi, m new to QT, i got a TEXTBROWSER in my MAINWINDOW which contains data that keeps on changing ...now i need to pass this changing data to my another TEXTBROWSER in QDIALOG....

Below is my code, using which i m only able to pass the first value of data, it's not updating itself.....HELP!

MainWindow.h

Code:

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Private:
QString txtoutput;     //this holds the data that keeps on updating
private slots:
    void cmdOutputDialog();

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MainWindow.cpp

Code:

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connect(ui->buttonclicked, SIGNAL(clicked()), this, SLOT(cmdOutputDialog()));
 
void MainWindow::cmdOutputDialog()
{
CmdOutputDialog *dlg=new CmdOutputDialog(this);
    dlg->display(txtoutput);
    dlg->exec();
}

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MyDialog.h

Code:

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public slots:
       void display(QString &text);
private:
QString m_disp;

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MyDialog.cpp

Code:

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void MyDialog::display(QString &text)
{
    m_disp=text;
    ui->textbrowser->setText(m_disp);
}

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Code:

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QString txtoutput;     //this holds the data that keeps on updating

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maybe post the update code too

Quote:

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Re: passing varying qstring value to QDialog from MAINWINDOW
Qt Code:

Code:

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QString txtoutput;     //this holds the data that keeps on updating

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To copy to clipboard, switch view to plain text mode
maybe post the update code too

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Actually I take the ffmpeg command line contents into that qstring

My code is below:

Code:

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//mainwindow.h
private:
    QProcess commandProcess ;
 
//mainwindow.cpp
 
   QByteArray cmdoutput = commandProcess.readAllStandardOutput();      
   txtoutput.append(cmdoutput);

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I assume that you call this once to show window:

Code:

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void MainWindow::cmdOutputDialog()
{
CmdOutputDialog *dlg=new CmdOutputDialog(this);
    dlg->display(txtoutput);
    dlg->exec();
}

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and you want the text to be constantly updated. To achieve this, you need to perform explicit update of the displayed text, the fact that you do:

Code:

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txtoutput.append(cmdoutput);

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not implies that string in 'dlg' will be updated, as this:

Code:

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dlg->display(txtoutput);

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assigns a copy of the original 'txtoutput' for display.
You need to update 'dlg' each time you receive new content:

Code:

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QByteArray cmdoutput = commandProcess.readAllStandardOutput();      
   txtoutput.append(cmdoutput);
   dlg->display(txtoutput);

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So, make CmdOutputDialog object a member of your MainWindow class, or define a signal in MainWindow and connect it to 'dlg' when you create it:

Code:

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CmdOutputDialog *dlg=new CmdOutputDialog(this);
    connect( this, SIGNAL(textUpdate(const QString&)), dlg, SLOT(display(const QString&)) );
    dlg->display(txtoutput);
    dlg->exec();
 
//... and then when text changes:
 
   txtoutput.append(cmdoutput);
   emit textUpdate(txtoutput);

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hey stampede very thanks for your reply.....

can you tell me when we emit the signal from mainwindow as

Code:

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emit textUpdate(txtoutput);

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then how do you receive that signal in CmdOutputDialog or how do you connect it......again thnx in advance...

Quote:

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how do you receive that signal in CmdOutputDialog or how do you connect it

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Check the last code snippet from my last post, there is a connection between signal from MainWindow and CmdOutputDialog. 'display' method is declared as a slot already, so you can have signals connected to it, only thing left to do is declare the signal in MainWindow and call 'emit'.
Read Signals And Slots documentation to know more about this mechanism.

Hey stampede thank u very much.....its working fine now....I was stuck with this problem since many days but now it is solved all due to you........you rock......:)