Difference between revisions of "Tab Order"

Revision as of 01:34, 15 July 2006

Introduction

This code provides Tab and Shift+Tab navigation through a list of widgets.

Create an instance of TabNavigation for each group of tab order, such as one per dialog. Specify the parent via a call to setParent(). This will help catch Tab and Shift+Tab keys, which will then properly cycle through the widgets specified via addWidget(). Note that addWidget() accepts window names as well as the handle of TabControl; this will automatically add the TabButton of that TabControl.

Files

TabNavigation.h

#ifndef _TabNavigation_h_
#define _TabNavigation_h_

#include <vector>
#include "CEGUI.h"

class TabNavigation
{
public:
	/* Specifies the parent or container.
		Used to trap Tab and Shift+Tab keys and relay them to the list of tab navigation. */
	void setParent(const CEGUI::String& window);

	/* Adds a TabControl widget.
		Its tab buttons will be added to the list of tab navigation. */
	void addWidget(const CEGUI::TabControl* tabControl);

	/* Adds a widget to the list of tab navigation.
		The order in which they are added corresponds to the tab order. */
	void addWidget(const CEGUI::String& window);

private:
	/* Ensures that the last known focused widget regains input. */
	bool _onParentActivated(const CEGUI::EventArgs& e);

	/* Handles non-tab key activation.
		This will ensure that the next tab key navigation will start from
		the relevant widget. */
	bool _onActivated(const CEGUI::EventArgs& e);

	/* Traps the Tab and Shift+Tab key and activates the next or previous 
		widget accordingly. */
	bool _onCharacterKey(const CEGUI::EventArgs& e);

	/* Maintains the list of widgets that participate in the tab order */
	std::vector<CEGUI::String> _tabNavigation;

	/* Maintains the last known widget to have the focus. */
	std::vector<CEGUI::String>::iterator _lastKnownFocus;
};

#endif // _TabNavigation_h_

TabNavigation.cpp

#include "c:/Ogre/ClansOfDestiny/src/src/GUI/TabNavigation.h"


/* These provide a visual focus cue when the scheme does not provide one
 *	 for every widget, such as TaharezLook's PushButton */
#define HACKED_FOCUS_GAIN(window) CEGUI::WindowManager::getSingleton().getWindow(window)->setAlpha(1.0f)
#define HACKED_FOCUS_LOSS(window) CEGUI::WindowManager::getSingleton().getWindow(window)->setAlpha(0.8f)

/* You can deactivate these hacked focus functions by defining the macro as a comment:
#define HACKED_FOCUS_GAIN(window) //
#define HACKED_FOCUS_LOSS(window) //
 */


void TabNavigation::setParent(const CEGUI::String& window)
{
	// Parent will feed the tab and shift+tab navigation to the list of monitored widgets
	CEGUI::WindowManager& wmgr = CEGUI::WindowManager::getSingleton();
	wmgr.getWindow(window)->subscribeEvent(CEGUI::Window::EventCharacterKey,	CEGUI::Event::Subscriber(&TabNavigation::_onCharacterKey,		this));
	wmgr.getWindow(window)->subscribeEvent(CEGUI::Window::EventActivated,		CEGUI::Event::Subscriber(&TabNavigation::_onParentActivated,	this));
}

void TabNavigation::addWidget(const CEGUI::String& window)
{
	// Add a widget to the list of widget navigation
	CEGUI::WindowManager& wmgr = CEGUI::WindowManager::getSingleton();

	wmgr.getWindow(window)->subscribeEvent(CEGUI::Window::EventCharacterKey,	CEGUI::Event::Subscriber(&TabNavigation::_onCharacterKey, this));
	wmgr.getWindow(window)->subscribeEvent(CEGUI::Window::EventActivated,		CEGUI::Event::Subscriber(&TabNavigation::_onActivated,	this));
	HACKED_FOCUS_LOSS(window);
	if(!_tabNavigation.size())
	{
		wmgr.getWindow(window)->activate(); // Activate the first widget by default
		HACKED_FOCUS_GAIN(window);
	}
	_tabNavigation.push_back(window);
	_lastKnownFocus = _tabNavigation.begin(); // Reset the iterator after each modification to the vector
}

void TabNavigation::addWidget(const CEGUI::TabControl* tabControl)
{
	// Add every tab buttons of a tab control
	CEGUI::WindowManager& wmgr = CEGUI::WindowManager::getSingleton();
	CEGUI::Window* tabPaneButtons = wmgr.getWindow(tabControl->getName() + "__auto_TabPane__Buttons");
	for(size_t idx = 0; idx < tabPaneButtons->getChildCount(); idx++)
	{
		addWidget(tabPaneButtons->getChildAtIdx(idx)->getName());
	}
}

bool TabNavigation::_onParentActivated(const CEGUI::EventArgs& e)
{
	// Parent is being activated, activate the widget with the last known focus
	if(_tabNavigation.size() && _lastKnownFocus != _tabNavigation.end())
	{
		CEGUI::WindowManager& wmgr = CEGUI::WindowManager::getSingleton();
		CEGUI::Window* window = wmgr.getWindow(*_lastKnownFocus);
		if(window)
			window->activate();
	}
	return true;
}

bool TabNavigation::_onActivated(const CEGUI::EventArgs& e)
{
	// A focus widget has been activated without tabbing (could be a mouse click)
	CEGUI::String currentlyFocused = static_cast<const CEGUI::WindowEventArgs&>(e).window->getName();
	if(_tabNavigation.size() 
		&& (_lastKnownFocus == _tabNavigation.end()
		|| (*_lastKnownFocus).compare(currentlyFocused))	)
	{
		if(_lastKnownFocus != _tabNavigation.end())
		{
			// These curly braces are IMPORTANT!!!
			HACKED_FOCUS_LOSS(*_lastKnownFocus);
		}
		for(_lastKnownFocus = _tabNavigation.begin(); _lastKnownFocus != _tabNavigation.end(); _lastKnownFocus++)
		{
			if(!(*_lastKnownFocus).compare(currentlyFocused))
			{
				HACKED_FOCUS_GAIN(currentlyFocused);
				return true;
			}
		}
		// Can't figure out who has the focus
		_lastKnownFocus = _tabNavigation.begin();
		HACKED_FOCUS_GAIN(*_lastKnownFocus);
	}
	return true;
}

bool TabNavigation::_onCharacterKey(const CEGUI::EventArgs& e)
{
	// Handle Tab (next) and Shift+Tab (previous) widget navigation
	assert(_tabNavigation.size() && "Don't simply call setParent(), also call addWidget()");
	if(static_cast<const CEGUI::KeyEventArgs&>(e).codepoint == 9) // Tab or Shift+Tab
	{
		// Identify who currently has the focus
		CEGUI::WindowManager& wmgr = CEGUI::WindowManager::getSingleton();
		std::vector<CEGUI::String>::iterator itFocus, itCurrent;
		if(_lastKnownFocus != _tabNavigation.end() && wmgr.getWindow(*_lastKnownFocus)->isActive())
		{
			// The last known focus is still in focus
			itCurrent = _lastKnownFocus;
		}
		else
		{
			// Figure out who (if anyone) has the focus
			for(itCurrent = _tabNavigation.begin(); itCurrent != _tabNavigation.end(); itCurrent++)
			{
				if(wmgr.getWindow(*itCurrent)->isActive())
				{
					// Found who has the focus
					break;
				}
			}
			if(itCurrent == _tabNavigation.end())
			{
				// We did not find who had the focus
				// Someone not in our list of monitored widgets has STOLEN the focus!
				// Use the last known focus or, if that's invalid, the first widget
				itCurrent = _lastKnownFocus != _tabNavigation.end() ? _lastKnownFocus : _tabNavigation.begin();
			}
		}

		// Change the focus
		itFocus = itCurrent; // The search starts from the currently focused
		CEGUI::Window* newWidget = 0;
		do
		{
			if(static_cast<const CEGUI::KeyEventArgs&>(e).sysKeys & CEGUI::Shift)
			{
				// Search previous
				if(itFocus == _tabNavigation.begin())
					itFocus = --_tabNavigation.end();
				else
					itFocus--;
			}
			else
			{
				// Search next
				itFocus++;
				if(itFocus == _tabNavigation.end())
					itFocus = _tabNavigation.begin();
			}
			newWidget = wmgr.getWindow(*itFocus);
			if(newWidget->isVisible() && !newWidget->isDisabled())
			{
				// We have found a valid focus target
				_lastKnownFocus = itFocus;
				break;
			}
			newWidget = 0;
		} while(itFocus != itCurrent); // Iterate while we're on a different widget

		if(newWidget)
		{
			// Remove the focus from this widget
			HACKED_FOCUS_LOSS(*itCurrent);

			// Give the focus to this widget
			newWidget->activate();
			HACKED_FOCUS_GAIN(newWidget->getName());
			return true;
		}
	}
	return false;
}

Demo

I did not provide a complete demo file. Instead here are the steps to create one. Add the following to WidgetGalore#WidgetGalore.h, within the initialiseSample() function, after the TabControl code and before the catch(Exception &e):

winWidgetsTabNavigation.setParent("winWidgets");
winWidgetsTabNavigation.addWidget("VerticalScrollbar");
winWidgetsTabNavigation.addWidget("Slider");
winWidgetsTabNavigation.addWidget("Combobox");
winWidgetsTabNavigation.addWidget("Editbox");
winWidgetsTabNavigation.addWidget("HorizontalScrollbar");
winWidgetsTabNavigation.addWidget("RadioButton_A");
winWidgetsTabNavigation.addWidget("RadioButton_B");
winWidgetsTabNavigation.addWidget("RadioButton_C");
winWidgetsTabNavigation.addWidget("RadioButton_1");
winWidgetsTabNavigation.addWidget("RadioButton_2");
winWidgetsTabNavigation.addWidget("RadioButton_3");
winWidgetsTabNavigation.addWidget("MultiColumnList");
winWidgetsTabNavigation.addWidget("Checkbox");
winWidgetsTabNavigation.addWidget("Spinner");
winWidgetsTabNavigation.addWidget("ScrollablePane");
winWidgetsTabNavigation.addWidget("Listbox");
winWidgetsTabNavigation.addWidget("MultiLineEditbox");
winWidgetsTabNavigation.addWidget("btnClose");

tabWindowTabNavigation.setParent("winTabControl");
tabWindowTabNavigation.addWidget(winTabControl); // Automatically add the tab buttons
tabWindowTabNavigation.addWidget("EditBoxPage1");
tabWindowTabNavigation.addWidget("EditBoxPage2");
tabWindowTabNavigation.addWidget("btnOk");
tabWindowTabNavigation.addWidget("btnCancel");
tabWindowTabNavigation.addWidget("btnApply");

Add these within the private section:

TabNavigation winWidgetsTabNavigation;
TabNavigation tabWindowTabNavigation;

Also use both WidgetGalore#main.cpp and WidgetGalore#WidgetGalore.layout.