简单的滚动条算法 (j2me描述)

void scrollBar(Graphics g,int total,int index,int each)

{

int startX =220;

int StartY = 20;

int EndX =220;

int EndY= 300;

int height = each*(EndY-StartY)/total;

int inc=(EndY-StartY-height)/(total-1);

EndY = inc*total+height+StartY;

g.setColor(0);

g.drawLine(startX, StartY, EndX, EndY);

g.setColor(0xff0000);

g.drawLine(startX, StartY+index*inc, startX, StartY+index*inc+height);

}

注： total 条目总数

index 当前选中条目

each 每屏显示的条目数

startX StartY EndX EndY 滚动条开始结束坐标

height 滚动条的高度

inc 滚动增量

EndY = inc*total+height+StartY; 消除误差(除不尽)