QT写入txt文件

QString filename = QFileDialog::getSaveFileName(this, tr("保存路径节点"), "", tr("Text files(*.txt)"));
if(filename.isEmpty())
return;
else
{
QFile file(filename);
if(! file.open(QIODevice::WriteOnly | QIODevice::Text))
{
QMessageBox::warning(this, tr("读取文件"), tr("无法打开文件：\n%1").arg(filename));
return;
}
else
{
QString content;
QString str1, str2, str3, str4, str5;
//录入内容
for(int i = 0; i < all_path_node.length(); i++)
{
str1.setNum(all_path_node[i].no);
str2.setNum(all_path_node[i].xpos, 'g', 4);
str3.setNum(all_path_node[i].ypos, 'g', 4);
str4.setNum(all_path_node[i].property);
str5.setNum(all_path_node[i].floor);
content += str1 + ", " + str2 + ", " + str3 + ", " + str4 + ", " + str5 + "\n";
}

//输出到文件
QTextStream in(&file);
in << content;
file.close();
}
}