QFileDialog dialog class

The QFileDialog dialog class is a subclass of the QDialog class, through which the file or directory to be opened/saved can be selected. Regarding this class, we only need to master the use of some static methods.

/*
通用参数:
  - parent: 当前对话框窗口的父对象也就是父窗口
  - caption: 当前对话框窗口的标题
  - dir: 当前对话框窗口打开的默认目录
  - options: 当前对话框窗口的一些可选项,枚举类型, 一般不需要进行设置, 使用默认值即可
  - filter: 过滤器, 在对话框中只显示满足条件的文件, 可以指定多个过滤器, 使用 ;; 分隔
    - 样式举例: 
	- Images (*.png *.jpg)
	- Images (*.png *.jpg);;Text files (*.txt)
  - selectedFilter: 如果指定了多个过滤器, 通过该参数指定默认使用哪一个, 不指定默认使用第一个过滤器
*/
// 打开一个目录, 得到这个目录的绝对路径
[static] QString QFileDialog::getExistingDirectory(
                  QWidget *parent = nullptr, 
                  const QString &caption = QString(), 
                  const QString &dir = QString(), 
                  QFileDialog::Options options = ShowDirsOnly);

// 打开一个文件, 得到这个文件的绝对路径
[static] QString QFileDialog::getOpenFileName(
    	          QWidget *parent = nullptr, 
    		  const QString &caption = QString(), 
                  const QString &dir = QString(), 
                  const QString &filter = QString(), 
                  QString *selectedFilter = nullptr, 
                  QFileDialog::Options options = Options());

// 打开多个文件, 得到这多个文件的绝对路径
[static] QStringList QFileDialog::getOpenFileNames(
    	          QWidget *parent = nullptr, 
                  const QString &caption = QString(), 
                  const QString &dir = QString(), 
                  const QString &filter = QString(), 
                  QString *selectedFilter = nullptr, 
                  QFileDialog::Options options = Options());

// 打开一个目录, 使用这个目录来保存指定的文件
[static] QString QFileDialog::getSaveFileName(
    		  QWidget *parent = nullptr, 
                  const QString &caption = QString(), 
                  const QString &dir = QString(), 
                  const QString &filter = QString(), 
                  QString *selectedFilter = nullptr, 
                  QFileDialog::Options options = Options());

example:

1. open local directory

void MainWindow::on_filedlg_clicked()
{
    
    
    QString dirName = QFileDialog::getExistingDirectory(
                      this,
                      "打开文件",
                      "E://BaiduNetdiskDownload");
    QMessageBox::information(this, "打开目录", "您选择的目录是: " + dirName);
}

running result:

2. open a local file

selectedFilter: If multiple filters are specified, specify which one to use by default through this parameter, and use the first filter by default if not specified

void MainWindow::on_filedlg_2_clicked()
{
    
    
    QString arg("Text files (*.txt)");
    QString fileName = QFileDialog::getOpenFileName(
              this, "Open File", "E://BaiduNetdiskDownload",
              "Images (*.png *.jpg);;Text files (*.txt)");
    QMessageBox::information(this, "打开文件", "您选择的文件是: " + fileName);
}

void MainWindow::on_filedlg_2_clicked()
{
    
    
    QString arg("Text files (*.txt)");
    QString fileName = QFileDialog::getOpenFileName(
              this, "Open File", "E://BaiduNetdiskDownload",
              "Images (*.png *.jpg);;Text files (*.txt)", &arg);
    QMessageBox::information(this, "打开文件", "您选择的文件是: " + fileName);
}

void MainWindow::on_filedlg_2_clicked()
{
    
    
    QString arg("Text files (*.txt *.doc)");
    QString fileName = QFileDialog::getOpenFileName(
              this, "Open File", "E://BaiduNetdiskDownload",
              "Images (*.png *.jpg);;Text files (*.txt *.doc)", &arg);
    QMessageBox::information(this, "打开文件", "您选择的文件是: " + fileName);
}

which ends up opening as:

3. open multiple local files

Just use string concatenation

void MainWindow::on_filedlg_3_clicked()
{
    
    
    QStringList fileNames = QFileDialog::getOpenFileNames(
              this, "Open File", "e:\\temp",
              "Images (*.png *.jpg);;Text files (*.txt)");
    QString names;
    for(int i=0; i<fileNames.size(); ++i)
    {
    
    
        names += fileNames.at(i) + " ";
    }
    QMessageBox::information(this, "打开文件(s)", "您选择的文件是: " + names);
}

4. Open the save file dialog

void MainWindow::on_filedlg_4_clicked()
{
    
    
    QString fileName = QFileDialog::getSaveFileName(this, "保存文件", "E://BaiduNetdiskDownload");
    QMessageBox::information(this, "保存文件", "您指定的保存数据的文件是: " + fileName);

}