zsdmenucanvas.java

基于j2me的高等代数计算工具

package edu.neu.aatk.canvas;

import javax.microedition.lcdui.Font;
import javax.microedition.lcdui.Graphics;
import javax.microedition.midlet.MIDletStateChangeException;

import edu.neu.aatk.AATK;


public class ZsdMenuCanvas extends AATKCanvas {

	public int selected = 0;
	public boolean selectKeyPressed = false;
	public static final int count = 10;
	private static final String[] LABELS = {
		"第一章 多项式",
		"第二章 行列式",
		"第三章 线形方程组",
		"第四章 矩阵",
		"第五章 二次型",
		"第六章 线形空间",
		"第七章 线形变换",
		"第八章 λ-矩阵",
		"第九章 欧几里得空间",
		"第十章 双线形函数与辛空间"};
	
	public ZsdMenuCanvas(String title, AATK aatk) {
		super(title, aatk);
	}
	
	private void paintMenu(Graphics g) {
		Font font = Font.getFont(Font.FACE_PROPORTIONAL, Font.STYLE_PLAIN, 
				Font.SIZE_MEDIUM);
		g.setFont(font); //设置字体
		g.setColor(128, 128, 128);
		
		for(int i = 0; i < LABELS.length; i++) {
			g.drawString(LABELS[i], 120, 60 + font.getHeight() * i + 5 * i, Graphics.BASELINE | Graphics.HCENTER);
		}

		g.setColor(0, 0, 0);

		g.drawString(LABELS[selected], 120, 60 + font.getHeight() * selected + 5 * selected, Graphics.BASELINE | Graphics.HCENTER);
		g.drawRoundRect(120 - font.stringWidth(LABELS[selected]) / 2 - 6,
		60 + font.getHeight() * selected + 5 * selected - font.getHeight(), 
		font.stringWidth(LABELS[selected]) + 12, 
		font.getHeight() + 6,
		5, 5);
		
		if(selectKeyPressed) {
			g.setColor(0, 0, 0);
			g.fillRoundRect(120 - font.stringWidth(LABELS[selected]) / 2 - 6,
					60 + font.getHeight() * selected + 5 * selected - font.getHeight(), 
					font.stringWidth(LABELS[selected]) + 12, 
					font.getHeight() + 6,
					5, 5);	
			g.setColor(255, 255, 255);
			g.drawString(LABELS[selected], 120, 60 + font.getHeight() * selected + 5 * selected, Graphics.BASELINE | Graphics.HCENTER);
		}
	
	}
	
	protected void paint(Graphics g) {
		super.paint(g);
		paintLeftCommand(g, "返回");
		paintMenu(g);
	}

}