Language Java Nosugar UI Code Layoutdemo.java

// 
//	LayoutDemo class
//	part of the set of documents known as Java no sugar.
//	Copyright (c) 1996 Sunil Gupta, sunil@magnetic.demon.co.uk
//	placed into the public domain by the author
//
import java.awt.*;
import java.applet.*;

public class LayoutDemo extends Applet
{
	//*******************************************************************
	// globals
	//*******************************************************************
	static final String GRID = "GRID";
	static final String GRIDBAG = "GRIDBAG";
	static final String BORDER = "BORDER";
	static final String FLOW = "FLOW";
	static final String CARD = "CARD";
	
	//*******************************************************************
	// instance variables
	//*******************************************************************
	Button grid_button, gridbag_button, border_button, flow_button;
	Panel cards;
	
	//*******************************************************************
	// applet methods
	//*******************************************************************
		public boolean action(Event event, Object arg)
		{
			CardLayout layout;
			
			if (event.target == grid_button)
			{
			layout = (CardLayout) cards.getLayout();
			layout.show(cards, GRID);
			return true;
			}
			else if (event.target == gridbag_button)
			{
			layout = (CardLayout) cards.getLayout();
			layout.show(cards, GRIDBAG);
			return true;
			}
			else if (event.target == border_button)
			{
			layout = (CardLayout) cards.getLayout();
			layout.show(cards, BORDER);
			return true;
			}
			else if (event.target == flow_button)
			{
			layout = (CardLayout) cards.getLayout();
			layout.show(cards, FLOW);
			return true;
			}
			return(false);
			
			
		}	
	
	public void init()
	{
		String style;
		
		style = getParameter("STYLE");
		
		if (style == null)				System.exit(1);
		else if (style.equals(GRID)	)	init_grid(this);
		else if (style.equals(GRIDBAG))	init_gridbag(this);
		else if (style.equals(BORDER))	init_border(this);
		else if (style.equals(FLOW)	)	init_flow(this);
		else if (style.equals(CARD)	)	init_card(this);
	}

	//*******************************************************************
	// private methods
	//*******************************************************************
	private void init_grid( Container container )
	{
		GridLayout layout;
		
		// ------------------create layout manager ----------------------
		layout = new GridLayout(3,3);
		container.setLayout(layout);

		// ------------------add some buttons ----------------------
		container.add ( new Button("components") );
		container.add ( new Button("are") );
		container.add ( new Button("laid") );
		container.add ( new Button("out") );
		container.add ( new Button("left to right") );
		container.add ( new Button("top to bottom"));
		container.add ( new Button("and") );
		container.add ( new Button("each have"));
		container.add ( new Button("the"));
		container.add ( new Button("same size"));
	}

	private void init_gridbag( Container container)
	{
		GridBagLayout layout;
		GridBagConstraints	c;
		Button	thing;
		
		
		// ------------------create layout manager ----------------------
		layout = new GridBagLayout();
		container.setLayout(layout);

		// ------------------add some buttons ----------------------
		c = new GridBagConstraints();
		thing = new Button ("GridBagLayout");
		c.gridx = 0; c.gridy = 0; c.gridwidth=2; c.gridheight=1;
		c.fill = GridBagConstraints.HORIZONTAL;
		layout.setConstraints(thing,c);
		container.add(thing);

		c = new GridBagConstraints();
		thing = new Button ("gives");
		c.gridx = 3; c.gridy = 0; c.gridwidth=1; c.gridheight=1;
		c.fill = GridBagConstraints.NONE;
		layout.setConstraints(thing,c);
		container.add(thing);

		c = new GridBagConstraints();
		thing = new Button ("better");
		c.gridx = 0; c.gridy = 2; c.gridwidth=1; c.gridheight=5;
		c.fill = GridBagConstraints.VERTICAL;
		layout.setConstraints(thing,c);
		container.add(thing);

		c = new GridBagConstraints();
		thing = new Button ("control");
		c.gridx = 1; c.gridy = 2; c.gridwidth=1; c.gridheight=1;
		c.fill = GridBagConstraints.NONE;
		layout.setConstraints(thing,c);
		container.add(thing);

		c = new GridBagConstraints();
		thing = new Button ("over");
		c.gridx = 1; c.gridy = 3; c.gridwidth=1; c.gridheight=1;
		c.fill = GridBagConstraints.NONE;
		layout.setConstraints(thing,c);
		container.add(thing);

		c = new GridBagConstraints();
		thing = new Button ("Positioning");
		c.gridx = 1; c.gridy = 4; c.gridwidth=2; c.gridheight=1;
		c.fill = GridBagConstraints.BOTH;
		layout.setConstraints(thing,c);
		container.add(thing);

		c = new GridBagConstraints();
		thing = new Button ("and");
		c.gridx = 2; c.gridy = 5; c.gridwidth=1; c.gridheight=1;
		c.fill = GridBagConstraints.BOTH;
		layout.setConstraints(thing,c);
		container.add(thing);
		
		c = new GridBagConstraints();
		thing = new Button ("size");
		c.gridx = 2; c.gridy = 6; c.gridwidth=2; c.gridheight=1;
		c.fill = GridBagConstraints.BOTH;
		layout.setConstraints(thing,c);
		container.add(thing);
	}

	private void init_border(Container container)
	{
		BorderLayout layout;
		TextArea textarea;
		
		// ------------------create layout manager ----------------------
		layout = new BorderLayout();
		container.setLayout(layout);

		// ------------------add some buttons ----------------------
		container.add ( "North",	new Button("North"));
		container.add ( "East",		new Button("East"));
		container.add ( "South",	new Button("South"));
		container.add ( "West",	new Button("West"));
		
		textarea = new TextArea();
		textarea.setEditable(false);
		textarea.appendText("Center\n-----\n\n");
		textarea.appendText("BorderLayout can contain\n");
		textarea.appendText("a maximum of 5 components.\n");
		textarea.appendText("The usefulness of these is limited.\n");
		textarea.appendText("In fact I cant think of even one\n");
		textarea.appendText("example where BorderLayout\n");
		textarea.appendText("would be better than GridBagLayout\n");
		container.add ( "Center",	textarea);
	}

	private void init_flow(Container container)
	{
		FlowLayout layout;
		
		// ------------------create layout manager ----------------------
		layout = new FlowLayout();
		container.setLayout(layout);

		// ------------------add some buttons ----------------------
		container.add ( new Button("components") );
		container.add ( new Button("are") );
		container.add ( new Button("laid") );
		container.add ( new Button("out") );
		container.add ( new Button("left to right") );
		container.add ( new Button("top to bottom") );
		container.add ( new Button("unlike GridLayout") );
		container.add ( new Button("components"));
		container.add ( new Button("don't") );
		container.add ( new Button("resize") );
	}

	private void init_card(Container container)
	{
		Panel controller_panel, card;
		
		// --------------- create a panel with the controlling buttons----
		controller_panel = new Panel();
		controller_panel.setLayout( new FlowLayout());
		grid_button = new Button(GRID);
		gridbag_button = new Button(GRIDBAG);
		flow_button = new Button(FLOW);
		border_button = new Button(BORDER);
		controller_panel.add( grid_button);
		controller_panel.add( gridbag_button);
		controller_panel.add( flow_button);
		controller_panel.add( border_button);
		
		// --------------- panel below has the card layout ----------------
		cards = new Panel();
		cards.setLayout ( new CardLayout() );
		
		card = new Panel();
		init_flow(card);
		cards.add(FLOW, card);
		
		card = new Panel();
		init_grid(card);
		cards.add(GRID, card);
		
		card = new Panel();
		init_gridbag(card);
		cards.add(GRIDBAG, card);

		card = new Panel();
		init_border(card);
		cards.add(BORDER, card);
		
		// ------------------create layout manager ----------------------
		this.setLayout(new GridLayout(2,1));
		this.add(controller_panel);
		this.add(cards);
	}
}

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