qt5base-lts/examples/uitools/textfinder/textfinder.cpp

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#include <QtUiTools>
#include <QtGui>
#include "textfinder.h"

//! [0]
TextFinder::TextFinder(QWidget *parent)
    : QWidget(parent)
{
    QWidget *formWidget = loadUiFile();

//! [1]
    ui_findButton = findChild<QPushButton*>("findButton");
    ui_textEdit = findChild<QTextEdit*>("textEdit");
    ui_lineEdit = findChild<QLineEdit*>("lineEdit");
//! [0] //! [1]

//! [2]
    QMetaObject::connectSlotsByName(this);
//! [2]

//! [3a]
    loadTextFile();
//! [3a]

//! [3b]
    QVBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(formWidget);
    setLayout(layout);
//! [3b]

//! [3c]
    setWindowTitle(tr("Text Finder"));
    isFirstTime = true;
}
//! [3c]

//! [4]
QWidget* TextFinder::loadUiFile()
{
    QUiLoader loader;

    QFile file(":/forms/textfinder.ui");
    file.open(QFile::ReadOnly);

    QWidget *formWidget = loader.load(&file, this);
    file.close();

    return formWidget;
}
//! [4]

//! [5]
void TextFinder::loadTextFile()
{
    QFile inputFile(":/forms/input.txt");
    inputFile.open(QIODevice::ReadOnly);
    QTextStream in(&inputFile);
    QString line = in.readAll();
    inputFile.close();

    ui_textEdit->append(line);
    ui_textEdit->setUndoRedoEnabled(false);
    ui_textEdit->setUndoRedoEnabled(true);
}
//! [5]

//! [6] //! [7]
void TextFinder::on_findButton_clicked()
{
    QString searchString = ui_lineEdit->text();
    QTextDocument *document = ui_textEdit->document();

    bool found = false;

    if (isFirstTime == false)
        document->undo();

    if (searchString.isEmpty()) {
        QMessageBox::information(this, tr("Empty Search Field"),
                "The search field is empty. Please enter a word and click Find.");
    } else {

        QTextCursor highlightCursor(document);  
        QTextCursor cursor(document);
        
        cursor.beginEditBlock();
//! [6]

        QTextCharFormat plainFormat(highlightCursor.charFormat());
        QTextCharFormat colorFormat = plainFormat;
        colorFormat.setForeground(Qt::red);

        while (!highlightCursor.isNull() && !highlightCursor.atEnd()) {
            highlightCursor = document->find(searchString, highlightCursor, QTextDocument::FindWholeWords);

            if (!highlightCursor.isNull()) {
                found = true;
                highlightCursor.movePosition(QTextCursor::WordRight,
                                       QTextCursor::KeepAnchor);
                highlightCursor.mergeCharFormat(colorFormat);
            }
        }

//! [8]
        cursor.endEditBlock();
//! [7] //! [9]
        isFirstTime = false;

        if (found == false) {
            QMessageBox::information(this, tr("Word Not Found"),
                "Sorry, the word cannot be found.");
        }    
    }
}
//! [8] //! [9]