7.9作业

 结果

void MainWindow::on_saveBtn_clicked()
{
    QFile filename=QFileDialog::getSaveFileName(this,
                                 "Save",
                                 "./",
                                 "所有文件(*.*);;头文件(*.h);;图片(*.png *.jpg);;文本(*.txt)"
                                 );

    if(!filename.exists())
    {
         if (filename.open(QIODevice::WriteOnly | QIODevice::Text | QIODevice::Truncate)) {

             QTextStream out(&filename);
             out << ui->textEdit->toPlainText();  // 将文本编辑器中的内容写入文件
             filename.close();
         } else {
             QMessageBox::critical(this, tr("Error"), tr("Could not save file"));
         }
    }

}