[[:oktatas:programozás:wxwidgets:wxWidgets kézikönyv|< wxWidgets kézikönyv]]

====== Widgets II ======

Ebben a részben folytatjuk a különböző widgetek bemutatását.

===== wxListBox =====


A wxListBox widget is used for displaying and working with a list of items. As it's name indicates, it is a rectangle that has a list of strings inside. We could use it for displaying a list of mp3 files, book names, module names of a larger project or names of our friends. A wxListBox can be created in two different states. In a single selection state or a multiple selection state. The single selection state is the default state. There are two significant events in wxListBox. The first one is the wxEVT_COMMAND_LISTBOX_SELECTED event. This event is generated when we select a string in a wxListBox. The second one is the wxEVT_COMMAND_LISTBOX_DOUBLE_CLICKED event. It is generated when we double click an item in a wxListBox. The number of elements inside a wxListBox is limited on GTK platform. According to the documentation, it is currently around 2000 elements. The elements are numbered from zero. Scrollbars are displayed automatically if needed. 


<code cpp Listbox.h>
#include <wx/wx.h>
#include <wx/listbox.h>

class MyPanel : public wxPanel
{
public:
      MyPanel(wxPanel *parent);

      void OnNew(wxCommandEvent& event);
      void OnRename(wxCommandEvent& event);
      void OnClear(wxCommandEvent& event);
      void OnDelete(wxCommandEvent& event);

      wxListBox *m_lb;

      wxButton *m_newb;
      wxButton *m_renameb;
      wxButton *m_clearb;
      wxButton *m_deleteb;

};

class Listbox : public wxFrame
{
public:
      Listbox(const wxString& title);

      void OnDblClick(wxCommandEvent& event);

      wxListBox *listbox;
      MyPanel *btnPanel;

};
  
const int ID_RENAME = 1;
const int ID_LISTBOX = 5;
</code>


<code cpp Listbox.cpp>
#include "listbox.h"
#include <wx/textdlg.h>

Listbox::Listbox(const wxString& title)
       : wxFrame(NULL, wxID_ANY, title, wxDefaultPosition, wxSize(270, 200))
{

    wxPanel * panel = new wxPanel(this, -1);

    wxBoxSizer *hbox = new wxBoxSizer(wxHORIZONTAL);

    listbox = new wxListBox(panel, ID_LISTBOX, 
        wxPoint(-1, -1), wxSize(-1, -1)); 

    hbox->Add(listbox, 3, wxEXPAND | wxALL, 20);

    btnPanel = new MyPanel(panel);
    hbox->Add(btnPanel, 2, wxEXPAND | wxRIGHT, 10);

    Connect(wxEVT_COMMAND_LISTBOX_DOUBLECLICKED, 
        wxCommandEventHandler(Listbox::OnDblClick));

    panel->SetSizer(hbox);
    Center();

}


MyPanel::MyPanel(wxPanel * parent)
         : wxPanel(parent, wxID_ANY)
{
    wxBoxSizer *vbox = new wxBoxSizer(wxVERTICAL);

    Listbox *lb = (Listbox *) parent->GetParent();
    m_lb = lb->listbox;

    m_newb = new wxButton(this, wxID_NEW, wxT("New"));
    m_renameb = new wxButton(this, ID_RENAME, wxT("Rename"));
    m_deleteb = new wxButton(this, wxID_DELETE, wxT("Delete"));
    m_clearb = new wxButton(this, wxID_CLEAR, wxT("Clear"));

    Connect(wxID_NEW, wxEVT_COMMAND_BUTTON_CLICKED, 
        wxCommandEventHandler(MyPanel::OnNew) );
    Connect(ID_RENAME, wxEVT_COMMAND_BUTTON_CLICKED, 
        wxCommandEventHandler(MyPanel::OnRename) );
    Connect(wxID_CLEAR, wxEVT_COMMAND_BUTTON_CLICKED, 
        wxCommandEventHandler(MyPanel::OnClear) );
    Connect(wxID_DELETE, wxEVT_COMMAND_BUTTON_CLICKED, 
        wxCommandEventHandler(MyPanel::OnDelete) );

    vbox->Add(-1, 20);
    vbox->Add(m_newb);
    vbox->Add(m_renameb, 0, wxTOP, 5);
    vbox->Add(m_deleteb, 0, wxTOP, 5);
    vbox->Add(m_clearb, 0, wxTOP, 5);

    SetSizer(vbox);

}


void MyPanel::OnNew(wxCommandEvent& event) 
{
    wxString str = wxGetTextFromUser(wxT("Add new item"));
    if (str.Len() > 0)
        m_lb->Append(str); 
}

void MyPanel::OnClear(wxCommandEvent& event) 
{
    m_lb->Clear();
}

void MyPanel::OnRename(wxCommandEvent& event) 
{
    wxString text;
    wxString renamed;

    int sel = m_lb->GetSelection();
    if (sel != -1) {
        text = m_lb->GetString(sel);
        renamed = wxGetTextFromUser(wxT("Rename item"), 
                    wxT("Rename dialog"), text);
    }

    if (!renamed.IsEmpty()) {
        m_lb->Delete(sel);
        m_lb->Insert(renamed, sel);
    }
}


void MyPanel::OnDelete(wxCommandEvent& event) 
{
    int sel = m_lb->GetSelection();
    if (sel != -1) {
        m_lb->Delete(sel);
    }
}


void Listbox::OnDblClick(wxCommandEvent& event) 
{
    wxString text;
    wxString renamed;

    int sel = listbox->GetSelection();
    if (sel != -1) {
        text = listbox->GetString(sel);
        renamed = wxGetTextFromUser(wxT("Rename item"), 
                    wxT("Rename dialog"), text);
    } 

    if (!renamed.IsEmpty()) {
        listbox->Delete(sel);
        listbox->Insert(renamed, sel);
    }
}
</code>


<code cpp main.h>
#include <wx/wx.h>

class MyApp : public wxApp
{
    public:
      virtual bool OnInit();
};
</code>

<code cpp main.cpp>
#include "main.h"
#include "Listbox.h"

IMPLEMENT_APP(MyApp)

bool MyApp::OnInit()
{  
      Listbox *listbox = new Listbox(wxT("Listbox"));
      listbox->Show(true);

      return true;
}
</code>

<code cpp>
listbox = new wxListBox(panel, ID_LISTBOX, 
     wxPoint(-1, -1), wxSize(-1, -1));
</code>


This is the constructor of the listbox widget. 
In our example, we have a list box and four buttons. The buttons are used to add, rename, delete and clear all items in the listbox. 

<code cpp>
wxString str = wxGetTextFromUser(wxT("Add new item"));
if (str.Len() > 0)
    m_lb->Append(str); 
</code>

To add a new string to the listbox, we display a wxGetTextFromUser dialog. We call the Append() method to append string to the listbox. 

<code cpp>
m_lb->Clear();
</code>


To clear all items is the easiest action to do. We just call the Clear() method. 
<code cpp>
int sel = m_lb->GetSelection();
if (sel != -1) 
{
      m_lb->Delete(sel);
}
</code>

To delete an item, we figure out the selected item. Then we call the Delete() method. 
Renaming an item requires several steps. 
<code cpp>
wxString text;
wxString renamed;
</code>

We define two local variables. 
<code cpp>
int sel = listbox->GetSelection();
if (sel != -1) 
{
     text = listbox->GetString(sel);
     renamed = wxGetTextFromUser(wxT("Rename item"), 
                 wxT("Rename dialog"), text);
} 
</code>

We get the selected string and save it to the renamed variable. 
<code cpp>
if (!renamed.IsEmpty()) 
{
      m_lb->Delete(sel);
      m_lb->Insert(renamed, sel);
}
</code>

We check whether the renamed variable is empty. This is to avoid inserting empty strings. Then we delete the old item and insert a new one. 

Listbox 

Figure: Listbox 


===== wxNotebook =====



wxNotebook widget joins multiple windows with corresponding tabs. You can position the Notebook widget using the following style flags: 
<code cpp>
  wxNB_LEFT
  wxNB_RIGHT
  wxNB_TOP
  wxNB_BOTTOM
</code>

The default position is wxNB_TOP.  


<code cpp Notebook.h>
#include <wx/wx.h>
#include <wx/notebook.h>
#include <wx/grid.h>

class Notebook : public wxFrame
{
public:
    Notebook(const wxString& title);

    void OnQuit(wxCommandEvent& event);

};


class MyGrid : public wxGrid
{
public:
    MyGrid(wxNotebook *parent);

};
</code>


<code cpp Notebook.cpp>
#include "Notebook.h"

Notebook::Notebook(const wxString& title)
       : wxFrame(NULL, wxID_ANY, title, wxDefaultPosition, wxSize(400, 350))
{

  wxNotebook *nb = new wxNotebook(this, -1, wxPoint(-1, -1), 
      wxSize(-1, -1), wxNB_BOTTOM);

  wxMenuBar *menubar = new wxMenuBar;
  wxMenu *file = new wxMenu;
  file->Append(wxID_EXIT, wxT("Quit"), wxT(""));
  menubar->Append(file, wxT("&File"));
  SetMenuBar(menubar);

  Connect(wxEVT_COMMAND_MENU_SELECTED, 
      wxCommandEventHandler(Notebook::OnQuit)); 

  MyGrid *grid1 = new MyGrid(nb);
  MyGrid *grid2 = new MyGrid(nb);
  MyGrid *grid3 = new MyGrid(nb);

  nb->AddPage(grid1, wxT("Sheet1"));
  nb->AddPage(grid2, wxT("Sheet2"));
  nb->AddPage(grid3, wxT("Sheet3"));

  CreateStatusBar();
  Center();
}


void Notebook::OnQuit(wxCommandEvent& event) 
{
  Close(true);
}

MyGrid::MyGrid(wxNotebook * parent)
       : wxGrid(parent, wxID_ANY)
{
  CreateGrid(30, 30);
  SetRowLabelSize(50);
  SetColLabelSize(25);
  SetRowLabelAlignment(wxALIGN_RIGHT, wxALIGN_CENTRE);
  SetLabelFont(wxFont(9, wxFONTFAMILY_DEFAULT, 
      wxFONTSTYLE_NORMAL, wxFONTWEIGHT_BOLD));

  for (int i = 0; i < 30 ; i++) {
      this->SetRowSize(i, 25);
  }

}
</code>


<code cpp main.h>
#include <wx/wx.h>

class MyApp : public wxApp
{
  public:
    virtual bool OnInit();
};
</code>

<code cpp main.cpp>
#include "main.h"
#include "Notebook.h"

IMPLEMENT_APP(MyApp)

bool MyApp::OnInit()
{

    Notebook *notebook = new Notebook(wxT("Notebook"));
    notebook->Show(true);

    return true;
}
</code>

 
In this example, we have created a notebook widget with three grids. The notebook widget is positioned at the bottom. 
<code cpp>
wxNotebook *nb = new wxNotebook(this, -1, wxPoint(-1, -1), 
     wxSize(-1, -1), wxNB_BOTTOM);
</code>

Here we create the notebook widget. 
<code cpp>
  nb->AddPage(grid1, wxT("Sheet1"));
  nb->AddPage(grid2, wxT("Sheet2"));
  nb->AddPage(grid3, wxT("Sheet3"));
</code>

We add three grid objects into the notebook widget. 

 Notebook 

Figure: Notebook widget 

===== wxScrolledWindow =====


This is one of the container widgets. It can be useful, when we have a larger area than a window can display. In our example, we demonstrate such a case. We place a large image into our window. When the window is smaller than our image, Scrollbars are displayed automatically. 


<code cpp scrolledwindow.h>
#include <wx/wx.h>
  
class ScrWindow : public wxFrame
{
  public:
    ScrWindow(const wxString& title);
  
};
</code>



<code cpp scrolledwindow.cpp>
#include "scrolledwindow.h"
  
ScrWindow::ScrWindow(const wxString& title)
       : wxFrame(NULL, wxID_ANY, title, wxDefaultPosition, wxSize(300, 200))
{
    wxImage::AddHandler(new wxJPEGHandler);
    wxScrolledWindow *sw = new wxScrolledWindow(this);
    
    wxBitmap bmp(wxT("castle.jpg"), wxBITMAP_TYPE_JPEG);
    wxStaticBitmap *sb = new wxStaticBitmap(sw, -1, bmp);
  
    int width = bmp.GetWidth();
    int height = bmp.GetHeight();
  
    sw->SetScrollbars(10, 10, width/10, height/10);
    sw->Scroll(50,10);
  
    Center();
}
</code>


<code cpp main.h>
#include <wx/wx.h>
  
class MyApp : public wxApp
{
    public:
      virtual bool OnInit();
};
</code>

<code cpp main.cpp>
#include "main.h"
#include "scrolledwindow.h"
  
IMPLEMENT_APP(MyApp)
  
bool MyApp::OnInit()
{
  
      ScrWindow *sw = new ScrWindow(wxT("ScrolledWindow"));
      sw->Show(true);
  
      return true;
}
</code>

 
In our example, we display a picture of a Spis castle. 
<code cpp>
wxImage::AddHandler(new wxJPEGHandler);
</code>

To handle jpg images, we must initiate the wxJPEGHandler. 

<code cpp>
wxScrolledWindow *sw = new wxScrolledWindow(this);
</code>

<code cpp>
wxBitmap bmp(wxT("castle.jpg"), wxBITMAP_TYPE_JPEG);
wxStaticBitmap *sb = new wxStaticBitmap(sw, -1, bmp);
</code>

We create a scroll window and put a static bitmap into it. 
<code cpp>
sw->SetScrollbars(10, 10, width/10, height/10);
</code>

We set the scrollbars. 
<code cpp>
sw->Scroll(50,10);
</code>

We scroll the window a bit. 

 Scrolled Window 

Figure: Scrolled Window