/*
* This file is part of lanterna (http://code.google.com/p/lanterna/).
*
* lanterna is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright (C) 2010-2017 Martin Berglund
*/
package com.googlecode.lanterna.gui2;
import com.googlecode.lanterna.TerminalTextUtils;
import com.googlecode.lanterna.TerminalPosition;
import com.googlecode.lanterna.TerminalSize;
import com.googlecode.lanterna.graphics.ThemeDefinition;
import com.googlecode.lanterna.input.KeyStroke;
import com.googlecode.lanterna.input.KeyType;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
/**
* The checkbox component looks like a regular checkbox that you can find in modern graphics user interfaces, a label
* and a space that the user can toggle on and off by using enter or space keys.
*
* @author Martin
*/
public class CheckBox extends AbstractInteractableComponent<CheckBox> {
/**
* Listener interface that can be used to catch user events on the check box
*/
public interface Listener {
/**
* This is fired when the user has altered the checked state of this {@code CheckBox}
* @param checked If the {@code CheckBox} is now toggled on, this is set to {@code true}, otherwise
* {@code false}
*/
void onStatusChanged(boolean checked);
}
private final List<Listener> listeners;
private String label;
private boolean checked;
/**
* Creates a new checkbox with no label, initially set to un-checked
*/
public CheckBox() {
this("");
}
/**
* Creates a new checkbox with a specific label, initially set to un-checked
* @param label Label to assign to the check box
*/
public CheckBox(String label) {
if(label == null) {
throw new IllegalArgumentException("Cannot create a CheckBox with null label");
}
else if(label.contains("\n") || label.contains("\r")) {
throw new IllegalArgumentException("Multiline checkbox labels are not supported");
}
this.listeners = new CopyOnWriteArrayList<Listener>();
this.label = label;
this.checked = false;
}
/**
* Programmatically updated the check box to a particular checked state
* @param checked If {@code true}, the check box will be set to toggled on, otherwise {@code false}
* @return Itself
*/
public synchronized CheckBox setChecked(final boolean checked) {
this.checked = checked;
runOnGUIThreadIfExistsOtherwiseRunDirect(new Runnable() {
@Override
public void run() {
for(Listener listener : listeners) {
listener.onStatusChanged(checked);
}
}
});
invalidate();
return this;
}
/**
* Returns the checked state of this check box
* @return {@code true} if the check box is toggled on, otherwise {@code false}
*/
public boolean isChecked() {
return checked;
}
@Override
public Result handleKeyStroke(KeyStroke keyStroke) {
if((keyStroke.getKeyType() == KeyType.Character && keyStroke.getCharacter() == ' ') ||
keyStroke.getKeyType() == KeyType.Enter) {
setChecked(!isChecked());
return Result.HANDLED;
}
return super.handleKeyStroke(keyStroke);
}
/**
* Updates the label of the checkbox
* @param label New label to assign to the check box
* @return Itself
*/
public synchronized CheckBox setLabel(String label) {
if(label == null) {
throw new IllegalArgumentException("Cannot set CheckBox label to null");
}
this.label = label;
invalidate();
return this;
}
/**
* Returns the label of check box
* @return Label currently assigned to the check box
*/
public String getLabel() {
return label;
}
/**
* Adds a listener to this check box so that it will be notificed on certain user actions
* @param listener Listener to fire events on
* @return Itself
*/
public CheckBox addListener(Listener listener) {
if(listener != null && !listeners.contains(listener)) {
listeners.add(listener);
}
return this;
}
/**
* Removes a listener from this check box so that, if it was previously added, it will no long receive any events
* @param listener Listener to remove from the check box
* @return Itself
*/
public CheckBox removeListener(Listener listener) {
listeners.remove(listener);
return this;
}
@Override
protected CheckBoxRenderer createDefaultRenderer() {
return new DefaultCheckBoxRenderer();
}
/**
* Helper interface that doesn't add any new methods but makes coding new check box renderers a little bit more clear
*/
public static abstract class CheckBoxRenderer implements InteractableRenderer<CheckBox> {
}
/**
* The default renderer that is used unless overridden. This renderer will draw the checkbox label on the right side
* of a "[ ]" block which will contain a "X" inside it if the check box has toggle status on
*/
public static class DefaultCheckBoxRenderer extends CheckBoxRenderer {
private static final TerminalPosition CURSOR_LOCATION = new TerminalPosition(1, 0);
@Override
public TerminalPosition getCursorLocation(CheckBox component) {
if(component.getThemeDefinition().isCursorVisible()) {
return CURSOR_LOCATION;
}
else {
return null;
}
}
@Override
public TerminalSize getPreferredSize(CheckBox component) {
int width = 3;
if(!component.label.isEmpty()) {
width += 1 + TerminalTextUtils.getColumnWidth(component.label);
}
return new TerminalSize(width, 1);
}
@Override
public void drawComponent(TextGUIGraphics graphics, CheckBox component) {
ThemeDefinition themeDefinition = component.getThemeDefinition();
if(component.isFocused()) {
graphics.applyThemeStyle(themeDefinition.getActive());
}
else {
graphics.applyThemeStyle(themeDefinition.getNormal());
}
graphics.fill(' ');
graphics.putString(4, 0, component.label);
if(component.isFocused()) {
graphics.applyThemeStyle(themeDefinition.getPreLight());
}
else {
graphics.applyThemeStyle(themeDefinition.getInsensitive());
}
graphics.setCharacter(0, 0, themeDefinition.getCharacter("LEFT_BRACKET", '['));
graphics.setCharacter(2, 0, themeDefinition.getCharacter("RIGHT_BRACKET", ']'));
graphics.setCharacter(3, 0, ' ');
if(component.isFocused()) {
graphics.applyThemeStyle(themeDefinition.getSelected());
}
else {
graphics.applyThemeStyle(themeDefinition.getNormal());
}
graphics.setCharacter(1, 0, (component.isChecked() ? themeDefinition.getCharacter("MARKER", 'x') : ' '));
}
}
}