1.打开单个文件

QString filename = QFileDialog::getOpenFileName(
   this,
   "Open Document",
   QDir::currentPath(),
   "Document files (*.doc *.rtf);;All files(*.*)");
if (!filename.isNull()) { //用户选择了文件
   // 处理文件
   QMessageBox::information(this, "Document", "Has document", QMessageBox::Ok | QMessageBox::Cancel);
} else // 用户取消选择
   QMessageBox::information(this, "Document", "No document", QMessageBox::Ok | QMessageBox::Cancel);

2. 可以选定多个文件的文件打开对话框

    QFileDialog::Options options;
    if (!native->isChecked())
        options |= QFileDialog::DontUseNativeDialog;
    QString selectedFilter;
    QStringList files = QFileDialog::getOpenFileNames(
                                this, tr("QFileDialog::getOpenFileNames()"),
                                openFilesPath,
                                tr("All Files (*);;Text Files (*.txt)"),
                                &selectedFilter,
                                options);
    if (files.count()) {
        openFilesPath = files[0];
        openFileNamesLabel->setText(QString("[%1]").arg(files.join(", ")));
    }