Qt - 選擇資料夾或特定的檔案

目前打算做一個小程式，可以讓使用選擇特定的檔案或資料夾

main.cpp

#include <QApplication>
#include "MyWidget.h"

int main (
  int argc,
  char *argv[]
  )
{
  QApplication app (argc, argv);

  MyWidget myWidget;

  myWidget.show ();

  return app.exec ();
}

MyWidget.h

#ifndef _MY_WIDGET_H_
#define _MY_WIDGET_H_

#include <QWidget>

class QLabel;
class QPushButton;
class QLineEdit;

class MyWidget : public QWidget {
  Q_OBJECT

  public:
    MyWidget (QWidget *parent = 0);

  private slots:
    void browse ();

  private:
    QLabel *myLabel;
    QPushButton *myPushButton;
    QLineEdit   *myLineEdit;
};

#endif //#ifndef _MY_WIDGET_H_

MyWidget.cpp

#include <QLabel>
#include <QPushButton>
#include <QLineEdit>
#include <QVBoxLayout>
#include <QFileDialog>

#include "MyWidget.h"

MyWidget::MyWidget (QWidget *parent) : QWidget (parent) {
  // do nothing
  myLabel = NULL;
  myLineEdit = NULL;
  myPushButton = NULL;

  myLabel = new QLabel (tr ("Target Name"), this);

  myLineEdit = new QLineEdit (this);

  myPushButton = new QPushButton (tr ("&Browse..."), this);

  connect (myPushButton, SIGNAL (clicked ()), SLOT (browse ()));

  QHBoxLayout *layout = new QHBoxLayout (this);
  layout->addWidget (myLabel);
  layout->addWidget (myLineEdit);
  layout->addWidget (myPushButton);

  this->setLayout (layout);
}

void MyWidget::browse () {
//  QString directory = QFileDialog::getExistingDirectory (this, tr ("Find Files"), QDir::currentPath ());

  QFileDialog myFileDialog (this);
  QString itemPath = myFileDialog.getOpenFileName (this, tr ("Open File"), QDir::currentPath (), tr ("All C++ files (*.cpp *.h)"));
  if (itemPath.isEmpty ()) {
    myLineEdit->setText (myFileDialog.directory ().absolutePath ());
  } else {
    myLineEdit->setText (itemPath);
  }
}

結果如下圖所示


本來打算只利用QFileDialog::getOpenFileName ()就可以選擇檔案和資料夾~
就是當使用者沒有選擇檔案的時候，同時按下「開啟」，這樣就會選擇目前視窗的路徑~
但是，沒有選擇檔案的時候，按開啟並不會回傳值。所以，只好讓使用都可以選擇目前要選擇檔案還是資料夾。
sample code如下：
main.cpp

#include <QApplication>
#include "MyWidget.h"

int main (
  int argc,
  char *argv[]
  )
{
  QApplication app (argc, argv);

  MyWidget myWidget;

  myWidget.show ();

  return app.exec ();
}

MyWidget.h

#ifndef _MY_WIDGET_H_
#define _MY_WIDGET_H_

#include <QWidget>

class QLabel;
class QPushButton;
class QLineEdit;

class MyWidget : public QWidget {
  Q_OBJECT

  public:
    MyWidget (QWidget *parent = 0);

  private slots:
    void browse ();
    void ChangeSelectFile (bool);

  private:
    QLabel *myLabel;
    QPushButton *myPushButton;
    QLineEdit   *myLineEdit;
    bool        SelectFile;
};

#endif //#ifndef _MY_WIDGET_H_

MyWidget.cpp

#include <QLabel>
#include <QPushButton>
#include <QLineEdit>
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QFileDialog>
#include <QGroupBox>
#include <QRadioButton>

#include "MyWidget.h"

MyWidget::MyWidget (QWidget *parent) : QWidget (parent) {

  //
  // init
  //
  myLabel = NULL;
  myLineEdit = NULL;
  myPushButton = NULL;

  //
  // Create Label component
  //
  myLabel = new QLabel (tr ("Target Name"), this);

  //
  // Create LineEdit component
  //
  myLineEdit = new QLineEdit (this);

  //
  // Create GroupBox and RadioButton component
  //
  QGroupBox *box = new QGroupBox (tr ("Select Type"));
  QRadioButton *radio1 = new QRadioButton (tr ("File"));
  QRadioButton *radio2 = new QRadioButton (tr ("Directory"));

  //
  // Set the default checked RadioButton for SelectFile
  //
  radio1->setChecked (true);
  SelectFile = true;

  //
  // Set RadioButton into QHBoxLayout
  // And set RadioButton into same GroupBox
  //
  QVBoxLayout *VLayout = new QVBoxLayout;
  VLayout->addWidget (radio1);
  VLayout->addWidget (radio2);
  box->setLayout (VLayout);

  //
  // Create QPushButton component
  //
  myPushButton = new QPushButton (tr ("&Browse..."), this);

  //
  // Add all the components into QHBoxLayout
  //
  QHBoxLayout *layout = new QHBoxLayout;
  layout->addWidget (myLabel);
  layout->addWidget (myLineEdit);
  layout->addWidget (box);
  layout->addWidget (myPushButton);

  //
  // Set the main Layout for MyWidget
  //
  this->setLayout (layout);

  //
  // Set the SIGNAL and SLOT for this component
  //
  connect (myPushButton, SIGNAL (clicked ()), SLOT (browse ()));
  connect (radio1, SIGNAL (toggled (bool)), this, SLOT (ChangeSelectFile (bool)));
}

void MyWidget::browse () {

  QString TargetItem;

  QFileDialog myFileDialog (this);
  if (SelectFile) {
    TargetItem = myFileDialog.getOpenFileName (this, tr ("Open File"), QDir::currentPath (), tr ("All C++ files (*.cpp *.h)"));
  } else {
    TargetItem = myFileDialog.getExistingDirectory (this, tr ("Select Folder"), QDir::currentPath ());
  }
  if (TargetItem.isEmpty ()) {
//    myLineEdit->setText (myFileDialog.directory ().absolutePath ());
//    myLineEdit->clear ();
  } else {
    myLineEdit->setText (TargetItem);
  }
}

void MyWidget::ChangeSelectFile (bool checked) {
  SelectFile = checked;
}

設定為選擇File：

當按Browse後，會出現以下的視窗，並且選擇一個限定的副檔名的檔案

當按下開啟後，會把選擇的檔案的路徑放在QLineEdit component裡面


另外，若選擇Directory的話，並且選擇Browse，會跳出以下的視窗


當按下確定後，就會把資料夾的路徑放在QLineEdit裡面，如下圖所示


參考資料：
QFileDialog Class Reference
Widgets and Layouts
Qt 第二章 创建对话框--子类化QDialog
QRadioButton Class Reference
QAbstractButton Class Reference
QLineEdit Class Reference