logcanvas.java

example2 众多JAVA实例源码...学习java基础的好帮手

package opusmicro.demos.game;

import java.util.Vector;

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Font;
import javax.microedition.lcdui.Graphics;

public class LogCanvas extends Canvas implements CommandListener{
	private Font font= Font.getDefaultFont(); 
	private int gintBeginIndex = 0;
	private int gintLineHeight = font.getHeight();
	private int w = getWidth();
	private int h = getHeight();
	private int scrollbarwidth = 6;
	private Command back;
	private MoveCanvas mc;
	private MoveMIDlet md;
	private Vector vector = new Vector();
	Vector logs = new Vector();
	private StringBuffer sb  = new StringBuffer();
	
	public static final byte DEBUG = 11;
	public static final byte INFO = 12;
	public static final byte ERROR = 13;
	public static final byte FETAL = 14;
	
	public LogCanvas(MoveCanvas mc, MoveMIDlet md) {
		this.mc = mc;
		this.md = md;
		init();
		
	}

	private void init() {
		back = new Command("Back",Command.BACK,1);
		addCommand(back);
		setCommandListener(this);
		
	}
	
	protected void keyPressed(int keycode) {
		int code = getGameAction(keycode);
		switch ( code) {
			case UP:
				if ( gintBeginIndex > 0) {
					gintBeginIndex--;
				}
				else {
					gintBeginIndex = 0;
					break;
				}
				repaint();
				break;
			case DOWN:
//				System.out.println("size = "+vector.size());
				if ( vector.size() * gintLineHeight <= h
						|| (vector.size() - gintBeginIndex) * gintLineHeight < h) {
					break;
				}
				gintBeginIndex++;
				repaint();
				break;
		}
	}
	
	private String getDebugMsg(){
		sb.delete(0, sb.length());
		for(int i=0;i<logs.size();i++){
			sb.append(logs.elementAt(i));
		}
		return sb.toString();
	}
	
	 public void log(int type, String msg) {
		try {
			String message = null;
			switch(type){
				case DEBUG:
					message = "[DEBUG] "+Utils.getTimeZone()+" "+msg+"\n";
					break;
				case INFO:
					message = "[INFO] "+Utils.getTimeZone()+" "+msg+"\n";
					break;
				case ERROR:
					message = "[ERROR] "+Utils.getTimeZone()+" "+msg+"\n";
					break;
				case FETAL:
					message = "[FETAL] "+Utils.getTimeZone()+" "+msg+"\n";
					break;
			}
			logs.insertElementAt(message, 0);
			if ( logs.size()>20)
				logs.removeElementAt(logs.size()-1);
		}
		catch (Exception e) {
			System.out.println("in debug() error!");
			e.printStackTrace();
		}
	}
	 
	protected void paint(Graphics g) {
//		System.out.println("font height "+font.getHeight());
		g.setColor(-1);
		g.fillRect(0, 0, w, h);
		g.setColor(0);
		vector.removeAllElements();
		vector = Utils.getSubsection(getDebugMsg(), font, w - scrollbarwidth-5, " ,.?!");
		for ( int i = gintBeginIndex ; i < vector.size() ; i++) {
			g.drawString((String) vector.elementAt(i), 1, gintLineHeight * (i - gintBeginIndex), Graphics.LEFT |Graphics.TOP);
			if ( (i - gintBeginIndex + 1) * gintLineHeight > h) {
				break;
			}
		}
		if ( (vector.size()) * gintLineHeight > h) {
			double position = Math.floor(((vector.size() + 1) * gintLineHeight - h+ .5) / gintLineHeight );
			double scrollbarheight = Math.floor((h + .8) / (position +1));
			int scrollbary = (int) Math.floor(scrollbarheight * (gintBeginIndex) + .8);
			g.setColor(0);
			g.fillRect(w - scrollbarwidth+1, scrollbary, scrollbarwidth, (int) scrollbarheight);
		}
	}

	public void commandAction(Command c, Displayable d) {
		if(c==back){
			gintBeginIndex = 0;
			md.display.setCurrent(mc);
		}
	}

}