Log Window Not Showing!

[Aviral 0]

Hi I am trying to create an application which displays recent 10 Logs from a file, and have checkboxes to filter the logs based on types,
here is my code:

logdisplay.cpp

#include "logdisplay.h"
#include <QFile>
#include <QHBoxLayout>
#include <QLabel>
#include <QTextStream>
#include <QTimer>
#include <QVBoxLayout>

LogDisplay::LogDisplay(QWidget *parent)
    : QWidget(parent)
{
    QVBoxLayout *mainLayout = new QVBoxLayout(this);

    QHBoxLayout *checkBoxLayout = new QHBoxLayout;
    infoCheckBox = new QCheckBox("INFO");
    infoCheckBox->setChecked(true);
    checkBoxLayout->addWidget(infoCheckBox);
    warnCheckBox = new QCheckBox("WARN");
    warnCheckBox->setChecked(true);
    checkBoxLayout->addWidget(warnCheckBox);
    debugCheckBox = new QCheckBox("DEBUG");
    debugCheckBox->setChecked(true);
    checkBoxLayout->addWidget(debugCheckBox);
    mainLayout->addLayout(checkBoxLayout);

    readLogs();

    QTimer *timer = new QTimer(this);
    connect(timer, &QTimer::timeout, this, &LogDisplay::refresh);
    timer->start(5000);
}



void LogDisplay::readLogs()
{
    QFile file("home/arpitk/QT Projects/logtail1/sample.log");
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
        return;

    QTextStream in(&file);
    QStringList logLines;
    while (!in.atEnd()) {
        logLines.append(in.readLine());
    }

    int logLinesCount = logLines.count();
    int startIndex = logLinesCount > 10 ? logLinesCount - 10 : 0;

    for (int i = startIndex; i < logLinesCount; i++) {
        QString message = logLines.at(i);
        QString level = message.left(5);
        if ((level == "INFO " && infoCheckBox->isChecked()) ||
            (level == "WARN " && warnCheckBox->isChecked()) ||
            (level == "DEBUG" && debugCheckBox->isChecked())) {
            mainLayout->addWidget(new QLabel(message));
        }
    }

    file.close();
}

    void LogDisplay::refresh()
            {
                QLayoutItem *child;
                while ((child = mainLayout->takeAt(1)) != 0) {
                    delete child->widget();
                    delete child;
                }
                readLogs();
            }
    LogDisplay::~LogDisplay()
    {
    }

main.cpp

#include "logdisplay.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    LogDisplay w;
    w.show();
    return a.exec();
}

The code is executing and checkboxes are displaying but Log Window is not showing?

The log window is not showing, Please help!

[jsulm]

This post is deleted!

[jsulm]

@Aviral-0 Did you do any debugging?
You call readLogs() only once in the constructor.
Does "home/arpitk/QT Projects/logtail1/sample.log" contain anything?
You should really first do at least some debugging...

[JonB]

@Aviral-0
I would start by changing the way you do stuff. All this creating individual QLabels for each message and deleting widgets/layout items is not a good way, for many reasons. For displaying log lines just append to a Q[Plain]TextEdit, or possibly use a QListView or QListWidget. You might also benefit from separating responsibilities, so readLogs() might just read the lines with no UI stuff and something else be responsible for displaying them.

[Aviral 0]

@JonB @jsulm I am new to all this, appreciate your patience!
This is my updated code, I have tried to keep all of your suggestions in mind. and this is I come up with.
The application is building but still no logs are shown :'(
And yes the file contains log information for which I am putting absolute path.

#include "logdisplay.h"
#include <QFileSystemWatcher>
#include <QFile>
#include <QTextStream>
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QCheckBox>
#include <QPlainTextEdit>
#include <QTextCursor>
#include <QToolBar>

LogDisplay::LogDisplay(QWidget *parent)
    : QMainWindow(parent)
{
    // Create the log display widget
    logDisplay = new QPlainTextEdit(this);
    logDisplay->setReadOnly(true);

    // Create the error checkbox
    errorCheckbox = new QCheckBox("Error", this);
    errorCheckbox->setChecked(true);

    // Create the warning checkbox
    warningCheckbox = new QCheckBox("Warning", this);
    warningCheckbox->setChecked(true);

    // Create the info checkbox
    infoCheckbox = new QCheckBox("Info", this);
    infoCheckbox->setChecked(true);

    // Create a horizontal layout for the checkboxes
    QHBoxLayout *checkboxLayout = new QHBoxLayout;
    checkboxLayout->addWidget(errorCheckbox);
    checkboxLayout->addWidget(warningCheckbox);
    checkboxLayout->addWidget(infoCheckbox);

    // Create a vertical layout for the log display and checkboxes
    QVBoxLayout *mainLayout = new QVBoxLayout;
    mainLayout->addWidget(logDisplay);
    mainLayout->addLayout(checkboxLayout);

    // Create a central widget and set its layout
    QWidget *centralWidget = new QWidget(this);
    centralWidget->setLayout(mainLayout);
    setCentralWidget(centralWidget);

    // Create a toolbar for the checkboxes
    QToolBar *filterToolBar = addToolBar("Filter");
    filterToolBar->addWidget(errorCheckbox);
    filterToolBar->addWidget(warningCheckbox);
    filterToolBar->addWidget(infoCheckbox);

    // Connect the checkbox state changed signals to the updateLogDisplay slot
    connect(errorCheckbox, &QCheckBox::stateChanged, this, &LogDisplay::updateLogDisplay);
    connect(warningCheckbox, &QCheckBox::stateChanged, this, &LogDisplay::updateLogDisplay);
    connect(infoCheckbox, &QCheckBox::stateChanged, this, &LogDisplay::updateLogDisplay);

    // Create a QFileSystemWatcher to monitor the log file
    QFileSystemWatcher *watcher = new QFileSystemWatcher(this);
    connect(watcher, &QFileSystemWatcher::fileChanged, this, &LogDisplay::updateLogList);
    watcher->addPath("log.txt");

    // Initialize the log display with the first set of logs
    updateLogList();
}

LogDisplay::~LogDisplay()
{
}

bool LogDisplay::updateLogList()
{
    // Open the log file
    QFile logFile("/home/arpitk/QT Projects/logtail1/sample.log");
    if (!logFile.open(QFile::ReadOnly | QFile::Text))
        return false;

    // Read the logs from the log file into the log line
    logList.clear();
    QTextStream in(&logFile);
    while (!in.atEnd()) {
    logList.prepend(in.readLine());
    }
    // Close the log file
    logFile.close();

    // Update the log display with the new logs
    updateLogDisplay();

    return true;
    }
void LogDisplay::updateLogDisplay()
{
// Clear the current log display
logDisplay->clear();
// Iterate over the logs in the log list
QTextCursor cursor(logDisplay->document());
for (int i = 0; i < logList.size(); ++i) {
    // Check if the log should be displayed based on the filter
    QString log = logList[i];
    if ((log.contains("Error") && errorCheckbox->isChecked()) ||
        (log.contains("Warning") && warningCheckbox->isChecked()) ||
        (log.contains("Info") && infoCheckbox->isChecked())) {
        // Insert the log into the log display
        cursor.insertText(log + "\n");
    }
}
}

[JonB]

@Aviral-0
You must either step through in a debugger or put in qDebug() messages. We (i.e. you!) need to know whether/when lines are being read from the log file and whether/when they are (attempted to be) displayed.

[Aviral 0]

@JonB @jsulm after debugging i got to know that QFile was not reading file, got it solved and not its working perfectly. Thankyou for all you help and kind support.