j2me 实现翻页功能的一个小例子

最新推荐文章于 2021-03-10 22:43:10 发布

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本文介绍了一个简单的Java ME应用示例，展示了如何使用自定义Canvas来显示分页的表格数据，并实现了基本的翻页功能。

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/*
create time: 2008-8-30 Administrator
*/
import javax.microedition.lcdui.*;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

public class PageMessage extends MIDlet {

public cCanvas canvas;

public PageMessage() {
canvas = new cCanvas();
}

protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
// TODO Auto-generated method stub

}

protected void pauseApp() {
// TODO Auto-generated method stub

}

protected void startApp() throws MIDletStateChangeException {
// TODO Auto-generated method stub
Display.getDisplay(this).setCurrent(canvas);
}

}

class cCanvas extends Canvas {
public String message[][] = { { "订单号", "股票名称", "价格", "数量" },
   { "bbb", "bbb", "bbb", "bbb" }, { "ccc", "bbb", "bbb", "bbb" },
   { "ddd", "bbb", "bbb", "bbb" }, { "eee", "bbb", "bbb", "bbb" },
   { "fff", "bbb", "bbb", "bbb" }, { "ggg", "bbb", "bbb", "bbb" } };

private static int startindex, currentindex, LINENUM = 3, COLNUM = 4;

public cCanvas() {

}

protected void paint(Graphics g) {
g.setColor(255, 255, 255); //刷屏
g.fillRect(0, 0, getWidth(), getHeight());

g.setColor(0); //设置显示字体颜色

drawPageStudentMessage(g);

drawSoftKey(g); //画左右键
}

public void drawSoftKey(Graphics g) {
  g.setColor(0); //设置显示字体颜色
  g.drawString("返回", 2, getHeight() - 2, Graphics.LEFT | Graphics.BOTTOM);
  g.drawString("下页", getWidth() - 2, getHeight() - 2, Graphics.RIGHT
    | Graphics.BOTTOM);
}

//数据内容，实现翻页功能
public void drawPageStudentMessage(Graphics g) {
  for (int currentindex = startindex; (currentindex < startindex
    + LINENUM)
    && currentindex < message.length; currentindex++) {
   for (int col = 0; col < COLNUM; col++) {
    g.drawString(message[currentindex][col], 60 * col,
      20 * (currentindex % LINENUM), Graphics.LEFT
        | Graphics.TOP);
   }
  }
}

public static int page;

protected void keyPressed(int keyCode) {
  if (keyCode == -7) //点击右键翻页
  {
   if (page < message.length / LINENUM)
    page++;

   startindex = (page * LINENUM);
  }
  if (keyCode == -6) //点击左键翻页
  {
   if (page > 0)
    page--;

   startindex = (page * LINENUM);
  }
  repaint();
}
}