Creating New Documents

To implemant the new file feature, first declare a protected slot in the header:

protected slots:
    void createNewDocument();

In the implementation file, instantiate the action and establish the connection:

newFileAct = new QAction(QIcon("new.png"), tr("New"), this);
newFileAct->setShortcut(QKeySequence::New);
newFileAct->setStatusTip(tr("Create new document"));
connect(newFileAct, &QAction::triggered, this, &EditorWindow::createNewDocument);

The slot implementation instantiates a fresh editor window:

void EditorWindow::createNewDocument()
{
    EditorWindow *nextWindow = new EditorWindow;
    nextWindow->show();
}

Opening Exsiting Files

The open file mechanism uses QFileDialog to select documents. The logic checks whether the current editor contains content—if empty, it loads into the current window; otherwise, it spawns a new instance.

Header declaration:

void openExistingFile();

Action configuration and signal connection:

openFileAct = new QAction(QIcon("open.png"), tr("Open"), this);
openFileAct->setShortcut(QKeySequence::Open);
connect(openFileAct, &QAction::triggered, this, &EditorWindow::openExistingFile);

The file opaning handler manages window state and document loading:

void EditorWindow::openExistingFile()
{
    QString path = QFileDialog::getOpenFileName(this, tr("Open Document"));
    
    if (path.isEmpty())
        return;
        
    QTextDocument *currentDoc = workspace->editor->document();
    
    if (currentDoc->isEmpty()) {
        populateEditor(path);
    } else {
        EditorWindow *alternate = new EditorWindow;
        alternate->show();
        alternate->populateEditor(path);
    }
}

The document population routine handles file I/O and text streaming:

void EditorWindow::populateEditor(const QString &path)
{
    QFile source(path);
    
    if (!source.open(QIODevice::ReadOnly | QIODevice::Text))
        return;
        
    QTextStream reader(&source);
    reader.setCodec("UTF-8");
    
    while (!reader.atEnd()) {
        workspace->editor->append(reader.readLine());
    }
}

Technical Considerations

The QTextEdit::document() method returns a QTextDocument pointer representing the underlying document structure. This object tracks content modifications, undo history, and formatting attributes. Checking isEmpty() determines whether the current editor instance contains unsaved or existing content.

QFileDialog::getOpenFileName accepts multiple parameters for customization:

• Parent widget reference for dialog positioning
• Window caption text
• Initial directory path
• File type filters (multiple patterns separated by double semicolons)
• Pointer to store the selected filter

Alternative file reading approaches include loading the entire contents into memory:

QFile source(filename);
if (source.open(QIODevice::ReadOnly)) {
    QByteArray rawData = source.readAll();
    QString content = QString::fromUtf8(rawData);
    editor->setPlainText(content);
}

This approach eliminates line-by-line processing but increases memory usage for large documents.