Thread Search in text file large

[marcos.miranda]

Hi,

Frist problem

When I press the Open File button and select the text file into a string search the system freezes. The code executed is the following:

QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"), "",
                       tr("Text Files (*.txt);;MSWord Files (*.doc)"));
     if (fileName != "") {
         QFile file(fileName);
         if (!file.open(QIODevice::ReadOnly | QIODevice::Text) ) {
             QMessageBox::critical(this, tr("Error"), tr("Could not open file"));
             return;
         }
 
         QTextStream in(&file);
         ui->txtEdit->setPlainText(in.readAll());
         file.close();

QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"), "",
                       tr("Text Files (*.txt);;MSWord Files (*.doc)"));
     if (fileName != "") {
         QFile file(fileName);
         if (!file.open(QIODevice::ReadOnly | QIODevice::Text) ) {
             QMessageBox::critical(this, tr("Error"), tr("Could not open file"));
             return;
         }

         QTextStream in(&file);
         ui->txtEdit->setPlainText(in.readAll());
         file.close();

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How can this not happen?


Second problem

When I start a search for a particular string in the text file back to the system freeze to end the search. The code executed is the following:

int vnumLinhaInit,vnumLinhasTotal;
 
    vnumLinhaInit=0;
    vnumLinhasTotal = ui->txtEdit->document()->lineCount();
    ui->txtEdit->moveCursor(QTextCursor::Start);
 
    while (ui->txtEdit->find(ui->lineEdit->text()))
    {
          ui->txtEdit->setTextBackgroundColor("yellow");
          ui->lblContador->setText(QString::number( vnumLinhaInit ));
          vnumLinhaInit += 1;
    }
 
    QMessageBox msgBox;
     msgBox.setText("A Busca Terminou !!!");
     msgBox.exec();

int vnumLinhaInit,vnumLinhasTotal;

    vnumLinhaInit=0;
    vnumLinhasTotal = ui->txtEdit->document()->lineCount();
    ui->txtEdit->moveCursor(QTextCursor::Start);

    while (ui->txtEdit->find(ui->lineEdit->text()))
    {
          ui->txtEdit->setTextBackgroundColor("yellow");
          ui->lblContador->setText(QString::number( vnumLinhaInit ));
          vnumLinhaInit += 1;
    }

    QMessageBox msgBox;
     msgBox.setText("A Busca Terminou !!!");
     msgBox.exec();

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How can this not happen?


As I understand my problem all forms are running in the same thread and have a heavy processing in both the opening of the text file as the moment of the search string in this large file system freezes. following drawing:

Thread Search 01.jpg


It could be done the following?

Run the search forms on different threads as in the main drawing below, so that the search processing can be without interfering with each other

Thread Search 02.jpg

How do? I do not have no idea!
If you or anyone has a solution to this freezing does not happen please post the code.

Thank you for your attention.

[wysota]

When I press the Open File button and select the text file into a string search the system freezes.

The system or your program?

When I start a search for a particular string in the text file back to the system freeze to end the search.

If by "the system" you mean your application, then it's quite normal since it takes some time for the while loop to execute.

How do? I do not have no idea!

You can do the search in an external thread (but not on the QTextEdit object!!!) or you can let the application process events (using QCoreApplication::processEvents()) from time to time while searching. Note that probably there are faster algorithms than using QTextEdit::find().

[marcos.miranda]

Hi, wysota

QCoreApplication :: processEvents (), I used inside the while loop has mitigated the problem, because i managed to open another form of search and start a new search simultaneously, was when I realized that this new form stopped interfering in the search form above to search old already open.

Is it possible when I call a new form of search it opens in a separate process of the program? How?



Thanks....

[wysota]

I don't really understand what you mean. The term "process" has a concrete meaning when it comes to computers, I don't think you really meant that.

[marcos.miranda]

Hi, wysota

Is it possible when I call a new form of search it opens in a separate Thread ?
How?



Thanks....

[wysota]

No, forms don't open "in threads". You can do the search in a separate thread and display the results in a window.

[marcos.miranda]

Hi everyone.

The QFile can open a file type. "Rtf and. Doc"?
How would the code if you can?


Thanks..

[wysota]

A file is a file. QFile doesn't care about content of the file you use. If you want to ask whether you can import an rtf or doc document to QTextEdit, then no, you'd have to have a dedicated import component.