3.10 实例：在指定文件系统中寻找一个文件.txt

qt的源代码

#ifndefWINDOW_H
#defineWINDOW_H
#include<QDialog>
class QComboBox;
class QDir;
class QLabel;
class QPushButton;
class QTableWidget;
class Window:public QDialog
{
Q_OBJECT
public:
Window(QWidget *parent=0);
private slots:
    void browse();
    void find();
private:
    QStringList findFiles(const QDir &directory， const QStringList &files，
                          const QString &text);
    void showFiles(const QDir &directory， const QStringList &files);
    QPushButton *createButton(const QString &text， const char *member);
    QComboBox *createComboBox(const QString &text = QString());
    void createFilesTable();
    QComboBox *fileComboBox;
    QComboBox *textComboBox;
    QComboBox *directoryComboBox;
    QLabel *fileLabel;
    QLabel *textLabel;
    QLabel *directoryLabel;
    QLabel *filesFoundLabel;
    QPushButton *browseButton;
    QPushButton *findButton;
    QTableWidget *filesTable;
};
#endif
#include <QtGui>
#include "window.h"
Window::Window(QWidget *parent)
    : QDialog(parent)
{
    browseButton = createButton(tr("&Browse...")， SLOT(browse()));
    findButton = createButton(tr("&Find")， SLOT(find()));
    fileComboBox = createComboBox(tr("*"));
    textComboBox = createComboBox();
    directoryComboBox = createComboBox(QDir::currentPath());
    fileLabel = new QLabel(tr("Named:"));
    textLabel = new QLabel(tr("Containing text:"));
    directoryLabel = new QLabel(tr("In directory:"));
    filesFoundLabel = new QLabel;
    createFilesTable();
QHBoxLayout *buttonsLayout = new QHBoxLayout;
    buttonsLayout->addStretch();
    buttonsLayout->addWidget(findButton);
    QGridLayout *mainLayout = new QGridLayout;
    mainLayout->addWidget(fileLabel， 0， 0);
    mainLayout->addWidget(fileComboBox， 0， 1， 1， 2);
    mainLayout->addWidget(textLabel， 1， 0);
    mainLayout->addWidget(textComboBox， 1， 1， 1， 2);
    mainLayout->addWidget(directoryLabel， 2， 0);
    mainLayout->addWidget(directoryComboBox， 2， 1);
    mainLayout->addWidget(browseButton， 2， 2);
    mainLayout->addWidget(filesTable， 3， 0， 1， 3);
    mainLayout->addWidget(filesFoundLabel， 4， 0);
    mainLayout->addLayout(buttonsLayout， 5， 0， 1， 3);
    setLayout(mainLayout);
    setWindowTitle(tr("Find Files"));
    resize(700， 300);
}
void Window::browse()
{
    QString directory = QFileDialog::getExistingDirectory(this，
                               tr("Find Files")， QDir::currentPath());
    if (!directory.isEmpty()) {
        directoryComboBox->addItem(directory);
        directoryComboBox->setCurrentIndex(directoryComboBox->currentIndex() + 1);
    }
}
void Window::find()
{
files Table->setRowCount(0);
QString fileName = fileComboBox->currentText();
    QString text = textComboBox->currentText();
    QString path = directoryComboBox->currentText();
QDir directory = QDir(path);
 QStringList files;
    if (fileName.isEmpty())
        fileName = "*";
    files = directory.entryList(QStringList(fileName)，
                                QDir::Files | QDir::NoSymLinks);
    if (!text.isEmpty())
        files = findFiles(directory， files， text);
    showFiles(directory， files);
}
QStringList Window::findFiles(const QDir &directory， const QStringList &files，
                              const QString &text)
{
    QProgressDialog progressDialog(this);
    progressDialog.setCancelButtonText(tr("&Cancel"));
    progressDialog.setRange(0， files.size());
    progressDialog.setWindowTitle(tr("Find Files"));
QStringList foundFiles;
    for (int i = 0; i < files.size(); ++i) {
        progressDialog.setValue(i);
        progressDialog.setLabelText(tr("Searching file number %1 of %2...")
                                    .arg(i).arg(files.size()));
        qApp->processEvents();
        if (progressDialog.wasCanceled())
            break;
QFile file(directory.absoluteFilePath(files[i]));
        if (file.open(QIODevice::ReadOnly)) {
            QString line;
            QTextStream in(&file);
            while (!in.atEnd()) {
                if (progressDialog.wasCanceled())
                    break;
                line = in.readLine();
if (line.contains(text)) {
                    foundFiles << files[i];
                    break;
                }
            }
        }
    }
    return foundFiles;
}
void Window::showFiles(const QDir &directory， const QStringList &files)
{
    for (int i = 0; i < files.size(); ++i) {
        QFile file(directory.absoluteFilePath(files[i]));
        qint64 size = QFileInfo(file).size();
        QTableWidgetItem *fileNameItem = new QTableWidgetItem(files[i]);
        fileNameItem->setFlags(Qt::ItemIsEnabled);
        QTableWidgetItem *sizeItem = new QTableWidgetItem(tr("%1 KB")
                                             .arg(int((size + 1023) / 1024)));
        sizeItem->setTextAlignment(Qt::AlignRight | Qt::AlignVCenter);
        sizeItem->setFlags(Qt::ItemIsEnabled);
        int row = filesTable->rowCount();
        filesTable->insertRow(row);
        filesTable->setItem(row， 0， fileNameItem);
        filesTable->setItem(row， 1， sizeItem);
    }
    filesFoundLabel->setText(tr("%1 file(s) found").arg(files.size()));
}
QPushButton *Window::createButton(const QString &text， const char *member)
{
    QPushButton *button = new QPushButton(text);
    connect(button， SIGNAL(clicked())， this， member);
    return button;
}
QComboBox *Window::createComboBox(const QString &text)
{
    QComboBox *comboBox = new QComboBox;
    comboBox->setEditable(true);
    comboBox->addItem(text);
    comboBox->setSizePolicy(QSizePolicy::Expanding， QSizePolicy::Preferred);
    return comboBox;
}
void Window::createFilesTable()
{
    filesTable = new QTableWidget(0， 2);
    QStringList labels;
    labels << tr("File Name") << tr("Size");
    filesTable->setHorizontalHeaderLabels(labels);
    filesTable->horizontalHeader()->setResizeMode(0， QHeaderView::Stretch);
    filesTable->verticalHeader()->hide();
    filesTable->setShowGrid(false);
}
#include <QApplication>
#include "window.h"
int main(int argc， char *argv[])
{
    QApplication app(argc， argv);
    Window window;
    window.show();
    return app.exec();
}