update text edit at run time.

[mbatra]

@jsulm

If I call
connect(watcher, SIGNAL(fileChanged(QString)), this, SLOT(slotFileChanged(QString)));

Signal doesn't get emitted at all.

[jsulm]

@mbatra There is NO need for emit at all!
I just realised that your code makes no sense:

void MainWindow::onstartButtonClicked()
{
    textEdit->show();
    bool b = watcher->addPath("D:/Putty_Log/Putty.log");
    qDebug()<<"\nAddPath Return Value = "<<b;
    emit slotFileChanged("D:/Putty_Log/Putty.log");
}

You need to call slotFileChanged in the slot connected to the signal from the watcher. Currently you call it in onstartButtonClicked - so why should it be called everytime the file is edited? Think about the logic.

[JonB]

@mbatra said in update text edit at run time.:

connect(watcher, SIGNAL(fileChanged(QString)), this, SLOT(slotFileChanged(QString)));

This ought be all you need. When the watcher sees a file change it emits the fileChanged() signal and your slotFileChanged() slot should be called.

[mbatra]

@JonB

Thanks Jon for your response.

Thank you everyone for the support. Its working fine now.

[JonB]

@mbatra
Now that you have it working, how about changing over to New Signal Slot Syntax:

connect(watcher, &QFileSystemWatcher::fileChanged, this, &MainWindow::slotFileChanged);

Use this instead of SIGNAL/SLOT() syntax going forward for all your connect()s, you will get e.g. compile-time checking that the signal and slot methods and arguments match.

[mbatra]

@JonB

Hi Jon,

Yes, I have used the new connect mechanism.

Thanks.

[mbatra]

@JonB

Hi,

I am facing another issue. File contents are not getting updating dynamically. If I add anything from the keyboard into the txt file slotchanged signal gets emitted. But if I run a batch file and that batch file creates a log file which I am reading into my application, contents are getting updated in the log file but text edit not getting updated at the same time.

Any help would be appreciated.

[jsulm]

@mbatra Do you mean the file does not exist at the beginning, but is created to some later point in time? If that is the case then I suggest to also add the folder where the file is created to QFileSystemWatcher, so that you get a notification when the file is created in that folder.
Because if you read the documentation:

bool QFileSystemWatcher::addPath(const QString &path)

Adds path to the file system watcher if path exists. The path is not added if it does not exist

"if path exists. The path is not added if it does not exist"

[JonB]

@mbatra
Exactly as @jsulm has written. If the file to be monitored does not yet exist you cannot place a QFileSystemWatcher on it. You have to watch the directory first to see file creation via directoryChanged(). Only once it has been created can you then start to monitor the file for fileChanged(), so a two-step process for your case.

[mbatra]

This post is deleted!