Widgets II
In this chapter, we will continue introducing various other widgets.
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.
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;
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.Printf(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.Printf(listbox->GetString(sel)); renamed = wxGetTextFromUser(wxT("Rename item"), wxT("Rename dialog"), text); } if (!renamed.IsEmpty()) { listbox->Delete(sel); listbox->Insert(renamed, sel); } }
main.h#include <wx/wx.h> class MyApp : public wxApp { public: virtual bool OnInit(); };
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; }
listbox = new wxListBox(panel, ID_LISTBOX,
wxPoint(-1, -1), wxSize(-1, -1));
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.
wxString str = wxGetTextFromUser(wxT("Add new item"));
if (str.Len() > 0)
m_lb->Append(str);
To add a new string to the listbox, we display a wxGetTextFromUser dialog. We call the Append() method to append string to the listbox.
m_lb->Clear();
To clear all items is the easiest action to do. We just call the Clear() method.
int sel = m_lb->GetSelection();
if (sel != -1) {
m_lb->Delete(sel);
}
To delete an item, we figure out the selected item. Then we call the Delete() method.
Renaming an item requires several steps.
wxString text; wxString renamed;
We define two local variables.
int sel = m_lb->GetSelection();
if (sel != -1) {
text.Printf(m_lb->GetString(sel));
renamed = wxGetTextFromUser(wxT("Rename item"),
wxT("Rename dialog"), text);
}
We get the selected string and save it to the renamed variable.
if (!renamed.IsEmpty()) {
m_lb->Delete(sel);
m_lb->Insert(renamed, sel);
}
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.
wxNotebook
wxNotebook widget joins multiple windows with corresponding tabs. You can position the Notebook widget using the following style flags:
- wxNB_LEFT
- wxNB_RIGHT
- wxNB_TOP
- wxNB_BOTTOM
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); };
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_CLOSE, 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); } }
main.h#include <wx/wx.h> class MyApp : public wxApp { public: virtual bool OnInit(); };
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; }
In this example, we have created a notebook widget with three grids. The notebook widget is positioned at the bottom.
wxNotebook *nb = new wxNotebook(this, -1, wxPoint(-1, -1),
wxSize(-1, -1), wxNB_BOTTOM);
Here we create the notebook widget.
nb->AddPage(grid1, wxT("Sheet1"));
nb->AddPage(grid2, wxT("Sheet2"));
nb->AddPage(grid3, wxT("Sheet3"));
We add three grid objects into the 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.
scrolledwindow.h#include <wx/wx.h> class ScrWindow : public wxFrame { public: ScrWindow(const wxString& title); };
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(); }
main.h#include <wx/wx.h> class MyApp : public wxApp { public: virtual bool OnInit(); };
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; }
In our example, we display a picture of a Spis castle.
wxImage::AddHandler(new wxJPEGHandler);
To handle jpg images, we must initiate the wxJPEGHandler.
wxScrolledWindow *sw = new wxScrolledWindow(this);
wxBitmap bmp(wxT("castle.jpg"), wxBITMAP_TYPE_JPEG);
wxStaticBitmap *sb = new wxStaticBitmap(sw, -1, bmp);
We create a scroll window and put a static bitmap into it.
sw->SetScrollbars(10, 10, width/10, height/10);
We set the scrollbars.
sw->Scroll(50,10);
We scroll the window a bit.
