wie Zeilennummern hinzugefügt werden: QTextEdit?

Question

Ich schreibe ein Visual Basic-IDE, und ich muss Zeilennummern hinzufügen QTextEdit und markieren Sie die aktuelle Zeile. Ich habe diese tutorial gefunden, aber es ist in Java geschrieben und ich schreibe mein Projekt in C++ so wo Tutorial wie das in C++ zu finden, oder wenn es eine gebrauchsfertige Komponente gibt?

danke.

Answer 1

Hier ist das Äquivalent Tutorial in C++:

Qt4: http://doc.qt.io/qt-4.8/qt-widgets-codeeditor-example.html

QT5: http://doc.qt.io/qt-5/qtwidgets-widgets-codeeditor-example.html

Answer 2

Ich weiß, dass Qt Tutorial mit QPlainTextEdit für Texteditor Implementierungen empfiehlt, und dass die Frage (außer wie erwähnt im Titel), ist allgemeiner als der Handel (absolut) mit einem QTextEdit Widget, aber es ist mir gelungen, das Verhalten zu implementieren (Zeilennummern + aktuelle Zeilennummer Highlight), und Ich denke, das könnte für einige Leute (wie mich) hilfreich sein, die wirklich mit dem Rich Text Widget weitermachen wollen und meine Implementierung teilen wollen (die weit davon entfernt ist perfekt zu sein - ziemlich schnell codiert ...).

LineNumberArea.h: (Wie "QPlainTextEdit" Tutorial)

class LineNumberArea : public QWidget 
{ 
    Q_OBJECT 

public: 
    LineNumberArea(QTextEdit *editor); 

    QSize sizeHint() const; 

protected: 
    void paintEvent(QPaintEvent *event); 

private: 
    QTextEdit *codeEditor; 
}; 

LineNumberArea.cpp: (Wie "QPlainTextEdit" Tutorial)

LineNumberArea::LineNumberArea(QTextEdit *editor) : QWidget(editor) { 
    codeEditor = editor; 
} 

QSize LineNumberArea::sizeHint() const { 
    return QSize(((QTextEditHighlighter *)codeEditor)->lineNumberAreaWidth(), 0); 
} 

void LineNumberArea::paintEvent(QPaintEvent *event) { 
    ((QTextEditHighlighter *)codeEditor)->lineNumberAreaPaintEvent(event); 
} 

>> qtextedithighlighter.h:

class QTextEditHighlighter : public QTextEdit 
{ 
    Q_OBJECT 

public: 

    explicit QTextEditHighlighter(QWidget *parent = 0); 

    int getFirstVisibleBlockId(); 
    void lineNumberAreaPaintEvent(QPaintEvent *event); 
    int lineNumberAreaWidth(); 

signals: 


public slots: 

    void resizeEvent(QResizeEvent *e); 

private slots: 

    void updateLineNumberAreaWidth(int newBlockCount); 
    void updateLineNumberArea(QRectF /*rect_f*/); 
    void updateLineNumberArea(int /*slider_pos*/); 
    void updateLineNumberArea(); 

private: 

    QWidget *lineNumberArea; 

}; 

>> qtextedithighlighter.cpp:

#include "qtextedithighlighter.h" 

QTextEditHighlighter::QTextEditHighlighter(QWidget *parent) : 
    QTextEdit(parent) 
{ 
    // Line numbers 
    lineNumberArea = new LineNumberArea(this); 
    /// 
    connect(this->document(), SIGNAL(blockCountChanged(int)), this, SLOT(updateLineNumberAreaWidth(int))); 
    connect(this->verticalScrollBar(), SIGNAL(valueChanged(int)), this, SLOT(updateLineNumberArea/*_2*/(int))); 
    connect(this, SIGNAL(textChanged()), this, SLOT(updateLineNumberArea())); 
    connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(updateLineNumberArea())); 
    /// 
    updateLineNumberAreaWidth(0); 
} 

int QTextEditHighlighter::lineNumberAreaWidth() 
{ 
    int digits = 1; 
    int max = qMax(1, this->document()->blockCount()); 
    while (max >= 10) { 
     max /= 10; 
     ++digits; 
    } 

    int space = 13 + fontMetrics().width(QLatin1Char('9')) * (digits); 

    return space; 
} 

void QTextEditHighlighter::updateLineNumberAreaWidth(int /* newBlockCount */) 
{ 
    setViewportMargins(lineNumberAreaWidth(), 0, 0, 0); 
} 


void QTextEditHighlighter::updateLineNumberArea(QRectF /*rect_f*/) 
{ 
    QTextEditHighlighter::updateLineNumberArea(); 
} 
void QTextEditHighlighter::updateLineNumberArea(int /*slider_pos*/) 
{ 
    QTextEditHighlighter::updateLineNumberArea(); 
} 
void QTextEditHighlighter::updateLineNumberArea() 
{ 
    /* 
    * When the signal is emitted, the sliderPosition has been adjusted according to the action, 
    * but the value has not yet been propagated (meaning the valueChanged() signal was not yet emitted), 
    * and the visual display has not been updated. In slots connected to this signal you can thus safely 
    * adjust any action by calling setSliderPosition() yourself, based on both the action and the 
    * slider's value. 
    */ 
    // Make sure the sliderPosition triggers one last time the valueChanged() signal with the actual value !!!! 
    this->verticalScrollBar()->setSliderPosition(this->verticalScrollBar()->sliderPosition()); 

    // Since "QTextEdit" does not have an "updateRequest(...)" signal, we chose 
    // to grab the imformations from "sliderPosition()" and "contentsRect()". 
    // See the necessary connections used (Class constructor implementation part). 

    QRect rect = this->contentsRect(); 
    lineNumberArea->update(0, rect.y(), lineNumberArea->width(), rect.height()); 
    updateLineNumberAreaWidth(0); 
    //---------- 
    int dy = this->verticalScrollBar()->sliderPosition(); 
    if (dy > -1) { 
     lineNumberArea->scroll(0, dy); 
    } 

    // Addjust slider to alway see the number of the currently being edited line... 
    int first_block_id = getFirstVisibleBlockId(); 
    if (first_block_id == 0 || this->textCursor().block().blockNumber() == first_block_id-1) 
     this->verticalScrollBar()->setSliderPosition(dy-this->document()->documentMargin()); 

// // Snap to first line (TODO...) 
// if (first_block_id > 0) 
// { 
//  int slider_pos = this->verticalScrollBar()->sliderPosition(); 
//  int prev_block_height = (int) this->document()->documentLayout()->blockBoundingRect(this->document()->findBlockByNumber(first_block_id-1)).height(); 
//  if (dy <= this->document()->documentMargin() + prev_block_height) 
//   this->verticalScrollBar()->setSliderPosition(slider_pos - (this->document()->documentMargin() + prev_block_height)); 
// } 

} 


void QTextEditHighlighter::resizeEvent(QResizeEvent *e) 
{ 
    QTextEdit::resizeEvent(e); 

    QRect cr = this->contentsRect(); 
    lineNumberArea->setGeometry(QRect(cr.left(), cr.top(), lineNumberAreaWidth(), cr.height())); 
} 


int QTextEditHighlighter::getFirstVisibleBlockId() 
{ 
    // Detect the first block for which bounding rect - once translated 
    // in absolute coordinated - is contained by the editor's text area 

    // Costly way of doing but since "blockBoundingGeometry(...)" doesn't 
    // exists for "QTextEdit"... 

    QTextCursor curs = QTextCursor(this->document()); 
    curs.movePosition(QTextCursor::Start); 
    for(int i=0; i < this->document()->blockCount(); ++i) 
    { 
     QTextBlock block = curs.block(); 

     QRect r1 = this->viewport()->geometry(); 
     QRect r2 = this->document()->documentLayout()->blockBoundingRect(block).translated(
        this->viewport()->geometry().x(), this->viewport()->geometry().y() - (
         this->verticalScrollBar()->sliderPosition() 
         )).toRect(); 

     if (r1.contains(r2, true)) { return i; } 

     curs.movePosition(QTextCursor::NextBlock); 
    } 

    return 0; 
} 

void QTextEditHighlighter::lineNumberAreaPaintEvent(QPaintEvent *event) 
{ 
    this->verticalScrollBar()->setSliderPosition(this->verticalScrollBar()->sliderPosition()); 

    QPainter painter(lineNumberArea); 
    painter.fillRect(event->rect(), Qt::lightGray); 
    int blockNumber = this->getFirstVisibleBlockId(); 

    QTextBlock block = this->document()->findBlockByNumber(blockNumber); 
    QTextBlock prev_block = (blockNumber > 0) ? this->document()->findBlockByNumber(blockNumber-1) : block; 
    int translate_y = (blockNumber > 0) ? -this->verticalScrollBar()->sliderPosition() : 0; 

    int top = this->viewport()->geometry().top(); 

    // Adjust text position according to the previous "non entirely visible" block 
    // if applicable. Also takes in consideration the document's margin offset. 
    int additional_margin; 
    if (blockNumber == 0) 
     // Simply adjust to document's margin 
     additional_margin = (int) this->document()->documentMargin() -1 - this->verticalScrollBar()->sliderPosition(); 
    else 
     // Getting the height of the visible part of the previous "non entirely visible" block 
     additional_margin = (int) this->document()->documentLayout()->blockBoundingRect(prev_block) 
       .translated(0, translate_y).intersect(this->viewport()->geometry()).height(); 

    // Shift the starting point 
    top += additional_margin; 

    int bottom = top + (int) this->document()->documentLayout()->blockBoundingRect(block).height(); 

    QColor col_1(90, 255, 30);  // Current line (custom green) 
    QColor col_0(120, 120, 120); // Other lines (custom darkgrey) 

    // Draw the numbers (displaying the current line number in green) 
    while (block.isValid() && top <= event->rect().bottom()) { 
     if (block.isVisible() && bottom >= event->rect().top()) { 
      QString number = QString::number(blockNumber + 1); 
      painter.setPen(QColor(120, 120, 120)); 
      painter.setPen((this->textCursor().blockNumber() == blockNumber) ? col_1 : col_0); 
      painter.drawText(-5, top, 
          lineNumberArea->width(), fontMetrics().height(), 
          Qt::AlignRight, number); 
     } 

     block = block.next(); 
     top = bottom; 
     bottom = top + (int) this->document()->documentLayout()->blockBoundingRect(block).height(); 
     ++blockNumber; 
    } 

} 

Hope this helfen ...