Qt创建文件

一、Qt创建文件夹

1、按照指定目录创建文件夹

QString dir_path = "./temp";
if(!QDir(dir_path).exists()){
    QDir().mkdir(dir_path);
}

2、在应用程序工作目录创建文件夹

QString app_path = QCoreApplication::applicationDirPath();
QString new_dir_path = app_path.append("/temp");
if(!QDir(new_dir_path).exists()){
    QDir().mkdir(dir_path);
}

3、在用户目录下创建文件夹

QString user_path = QStandardPaths::writableLocation(QStandardPaths::HomeLocation);
QString new_dir_path = user_path.append("/temp");
if(!QDir(new_dir_path).exists()){
    QDir().mkdir(dir_path);
}

二、Qt创建文件到选择的目录

1、使用QFileDialog选择目录并创建文件

QStringList fileNames = QFileDialog::getOpenFileNames(this, tr("Open file"), "/", "Text files (*.txt)");
foreach(QString file, fileNames)
{
    QFile myFile(file);
    if(!myFile.open(QIODevice::ReadWrite | QIODevice::Text))
        continue;
    QTextStream out(&myFile);
    out << "This is a test file." << endl;
    myFile.close();
}

2、使用QLineEdit指定目录并创建文件

QString filePath = ui->lineEdit->text();
QFile file(filePath);
if(file.open(QIODevice::WriteOnly)){
    QTextStream stream(&file);
    stream << "Qt create file success!" << endl;
    file.close();
}
else{
    qDebug() << "Qt create file error.";
}

3、使用QFileDevice指定目录并创建文件

QString filePath = "./temp/test.txt";
QFileDevice::Permissions permission = QFileDevice::WriteUser | QFileDevice::ReadUser | QFileDevice::WriteGroup | QFileDevice::ReadGroup | QFileDevice::WriteOther | QFileDevice::ReadOther;
QFile file(filePath);
if (file.open(QIODevice::WriteOnly | QIODevice::Append))
{
    QTextStream stream(&file);
    stream << "Qt create file success!" << endl;
    file.close();
}
else
{
    qDebug() << "Qt create file error.";
}
file.setPermissions(permission);

三、Qt创建文件txt

1、使用QFile创建txt文件

QString filePath = "./temp/test.txt";
QFile file(filePath);
if(file.open(QIODevice::WriteOnly)){
    QTextStream stream(&file);
    stream << "Qt create file success!" << endl;
    file.close();
}
else{
    qDebug() << "Qt create file error.";
}

2、使用QTextDocument创建txt文件

QString filePath = "./temp/test.txt";
QFile file(filePath);
if(file.open(QIODevice::WriteOnly)){
    QTextDocument doc;
    doc.setPlainText("Qt create file success!");
    QTextStream stream(&file);
    stream << doc.toPlainText();
    file.close();
}
else{
    qDebug() << "Qt create file error.";
}

3、使用QIODevice创建txt文件

QString filePath = "./temp/test.txt";
QFileDevice::Permissions permission = QFileDevice::WriteUser | QFileDevice::ReadUser | QFileDevice::WriteGroup | QFileDevice::ReadGroup | QFileDevice::WriteOther | QFileDevice::ReadOther;
QFile file(filePath);
if (file.open(QIODevice::WriteOnly | QIODevice::Append))
{
    QTextStream stream(&file);
    stream << "Qt create file success!" << endl;
    file.close();
}
else
{
    qDebug() << "Qt create file error.";
}
file.setPermissions(permission);

四、Qt保存文件对话框

使用QFileDialog打开保存文件对话框并保存文件

QString saveFilePath = QFileDialog::getSaveFileName(this, tr("Save file"), "./temp/test.txt");
if(saveFilePath.isEmpty()){
    qDebug() << "Save file path is empty.";
}
else{
    QFile file(saveFilePath);
    if(!file.open(QIODevice::ReadWrite | QIODevice::Text)){
        qDebug() << "Open save file failed.";
    }
    else{
        QTextStream out(&file);
        out << "Qt save file success." << endl;
        file.close();
    }
}

五、Qt创建文件夹失败

判断文件夹是否存在，不存在则创建

QString dir_path = "./temp";
if(!QDir(dir_path).exists()){
    if(QDir().mkdir(dir_path)){
        qDebug() << "Create directory success.";
    }
    else{
        qDebug() << "Create directory failed.";
    }
}

六、Qt创建一个文件.jpg

使用QFile创建jpg文件，然后写入数据

QString filePath = "./temp/test.jpg";
QFile file(filePath);
if(file.open(QIODevice::WriteOnly)){
    QDataStream out(&file);
    QImage image("./1.png");
    QByteArray bts;
    QBuffer buf(&bts);
    image.save(&buf, "PNG");
    out.writeRawData(bts.data(), bts.size());
    file.close();
}
else{
    qDebug() << "Qt create file error.";
}

七、Qt创建文件夹函数

以下是一个通用的创建文件夹的函数

void createDir(QString dirPath)
{
    QDir dir(dirPath);
    if (!dir.exists())
    {
        bool ok = dir.mkpath(dirPath);
        if (!ok)
        {
            qDebug()<< QString("Creat folder Failed: %1").arg(dirPath);
            return;
        }
        qDebug()<< "Creat folder Success:" << dirPath;
    }
}

八、Qt创建文件对话框

使用QFileDialog打开文件创建对话框

QString filePath = QFileDialog::getSaveFileName(this, tr("Save File"), "./temp/test.txt");
if(filePath.isEmpty()){
    qDebug() << "Save file path is empty.";
}
else{
    QFile file(filePath);
    if(!file.open(QIODevice::ReadWrite | QIODevice::Text)){
        qDebug() << "Open save file failed.";
    }
    else{
        QTextStream out(&file);
        out << "Qt create file success." << endl;
        file.close();
    }
}

九、Qt创建文件并写入

创建文件并写入内容

QString filePath = "./temp/test.txt";
QFile file(filePath);
if(file.open(QIODevice::WriteOnly)){
    QTextStream stream(&file);
    stream << "Qt create file success!" << endl;
    file.close();
}
else{
    qDebug() << "Qt create file error.";
}

十、Qt创建文件夹程序

包含GUI的Qt程序可以使用如下代码创建文件夹

void MainWindow::on_pushButton_clicked()
{
    QString newDirPath = ui->lineEdit->text();
    if(!QDir(newDirPath).exists()){
        QDir().mkdir(newDirPath);
        QMessageBox::information(this, tr("Information"), tr("Create Directory Success!"));
    }
    else{
        QMessageBox::information(this, tr("Information"), tr("Directory already exists!"));
    }
}