The wxWidgets programming tutorial (7. Wigets part 1)

The wxWidgets programming tutorial (7. Wigets part 1)

Widgets

In this chapter, we will show small examples of several widgets, available in wxWidgets. Widgets are builing blocks of our applications. wxWidgets consists of a large amout of useful widgets. Widget is a basic GUI object by definition. A widget gave wxWidgets toolkit a name. This term is used on UNIX systems. On windows, a widget is usually called a control.

wxCheckBox

wxCheckBox is a widget that has two states. On and Off. It is a box with a label. The label can be set to the right or to the left of the box. If the checkbox is checked, it is represented by a tick in a box. A checkbox can be used to show/hide splashscreen at startup, toggle visibility of a toolbar etc.

In our example, we display one checkbox on the window. We toggle the titlel of the window by clicking on the checkbox.

m_cb = new wxCheckBox(panel, ID_CHECKBOX, wxT("Show title"),

wxPoint(20, 20));

m_cb->SetValue(true);

We create a checkbox. By default, the title is visible. So we check the checkbox by calling the method SetValue().

Connect(ID_CHECKBOX, wxEVT_COMMAND_CHECKBOX_CLICKED,

wxCommandEventHandler(CheckBox::OnToggle));

If we click on the checkbox, a wxEVT_COMMAND_CHECKBOX_CLICKED event is generated. We connect this event to the user defined OnToggle() method.

if (m_cb->GetValue()) {

this->SetTitle(wxT("CheckBox"));

} else {

this->SetTitle(wxT(" "));

}

Inside the OnToggle() method, we check the state of the checkbox. If it is checked, we display "CheckBox" string in the titlebar, otherwise we clear the title.

wxBitmapButton

A bitmap button is a button, that displays a bitmap. A bitmap button can have three other states. Selected, focused and displayed. We can set a specific bitmap for those states.

In our example, we have a slider and a bitmap button. We simulate a volume control. By dragging the handle of a slider, we change a bitmap on the button.

wxImage::AddHandler( new wxPNGHandler );

We will use PNG images, so we must initialize a PNG image handler.