calendarcanvas.java

J2ME MIDP 2.0 无线设备编程的一些源码

//CalendarCanvas.java 实现日历画布 CalendarCanvas 类
package calendar;
import java.util.*;
import javax.microedition.lcdui.*;

public class CalendarCanvas extends Canvas implements CommandListener 
{
    //菜单命令，分别对应 下月，上月，下年，上年，选择当前日期
    public static Command nextMonthCmd =new Command("NextMonth",Command.SCREEN,1);
    public static Command prevMonthCmd =new Command("PrevMonth",Command.SCREEN,1);
    public static Command nextYearCmd =new Command("NextYear",Command.SCREEN,1);
    public static Command prevYearCmd =new Command("PrevYear",Command.SCREEN,1);
    public static Command selectCmd =new Command("Select",Command.EXIT,2);
    //周日到周六的文字
    private static String weekDays= new String("SunMonTueWedThuFriSat");
    //字体，用于显示正常的日期，假日，重要日期，含有重要事件的假日，可以根据需要修改
    //考虑到性能的问题可以把字体对象的数量减少
    private static Font[ ] fontShow={Font.getFont(Font.FACE_SYSTEM,Font.STYLE_PLAIN,Font.SIZE_SMALL),
                        Font.getFont(Font.FACE_SYSTEM,Font.STYLE_PLAIN,Font.SIZE_SMALL),
                        Font.getFont(Font.FACE_SYSTEM,Font.STYLE_UNDERLINED,Font.SIZE_SMALL),
                        Font.getFont(Font.FACE_SYSTEM,Font.STYLE_UNDERLINED|Font.STYLE_BOLD,Font.SIZE_SMALL)};
    //颜色，用于显示不同类型日期的背景和字体颜色，可以根据需要修改
    private static int[ ] clrBk=  {0x00ffffff,0x00999999,0x00ffffff,0x00999999};
    private static int[ ] clrFont={0x00000000,0x00000000,0x00000000,0x00000000};
    //被选中的日期所使用的字体和颜色，可以根据需要修改
    private static Font fontSelected=Font.getFont(Font.FACE_SYSTEM,Font.STYLE_BOLD,Font.SIZE_SMALL);
    private static int clrSelectedBk=0x00cccccc, clrSelectedFont = 0x00000000;
    //记录每月天数
    private static int[ ] daysOfMonth={31,28,31,30,31,30,31,31,30,31,30,31};
    //日期选择事件处理对象
    protected DateSelectListener dateListener =null;
    //重要日期判断对象
    protected ImportDateFilter dateFilter = null;
    //月份变动事件处理对象
    protected MonthChangeListener monthListener =null;
    private int width, height;//保存屏幕大小
    private int startX;//保存绘图开始的X坐标位置，便于日历居中显示
    private int iCellWidth,iCellHeight;//日历显示参数，每个日期所占空间
    private Calendar calTemp;//日期对象
    //当前焦点所在的日期
    private int curYear, curMonth, curDay;
    //构造器
    public CalendarCanvas(Date date)
    {
        super();
        //增加菜单
        addCommand(selectCmd);
        addCommand(nextMonthCmd);
        addCommand(prevMonthCmd);
        addCommand(nextYearCmd);
        addCommand(prevYearCmd);
        setCommandListener(this);
        //设置当天的日期作为选中的日期
        calTemp = Calendar.getInstance();
        if(date != null)
            calTemp.setTime(date);
        curYear = calTemp.get(Calendar.YEAR);
        curMonth = calTemp.get(Calendar.MONTH);
        curDay = calTemp.get(Calendar.DAY_OF_MONTH);
        //根据字体计算显示每个日期所需要高度和宽度
        iCellWidth = fontSelected.substringWidth(weekDays, 0, 3)+2;
        iCellHeight = fontSelected.getHeight()+2;
    }
    //设置重要日期判断对象
    public void setImportDateFilter(ImportDateFilter filter)
    {
        dateFilter = filter;
    }
    //设置日期选择监听对象
    public void setDateSelectListener(DateSelectListener listener)
    {
        dateListener = listener;
    }
    //设置月份变动监听对象
    public void setMonthChangeListener(MonthChangeListener listener)
    {
        monthListener = listener;
    }
    //得到当前焦点所在的日期
    public Calendar getFocusDate()
    {
        calTemp.set(Calendar.YEAR, curYear);
        calTemp.set(Calendar.MONTH, curMonth);
        calTemp.set(Calendar.DAY_OF_MONTH,1);
        return calTemp;
    }
    //在画布显示前保存屏幕尺寸
    protected void showNotify()
    {
        height = getHeight();
        width = getWidth();
        startX = (width- 7*iCellWidth)/2;
    }
    //绘制日历
    protected void paint(Graphics g)
    {
        //填充屏幕
        g.setColor(0x00ffffff);
        g.fillRect(0,0,width,height);
        //显示当前月的日历
        paintMonth(g);
    }
    //处理按键事件
    protected void keyPressed(int keyCode)
    {
        int newDay =curDay;
        switch(getGameAction(keyCode))
        {
            case UP: //转到上一周
                if(curDay>7)
                    newDay -=7;
            break;
            case DOWN: //转到下一周
                if(curDay<=getDaysOfMonth(curYear, curMonth)-7)
                    newDay +=7;
            break;
            case LEFT: //转到上一天
                if(curDay>1)
                    newDay --;
            break;
            case RIGHT: //转到下一天
                if(curDay<getDaysOfMonth(curYear, curMonth) )
                    newDay ++;
            break;
            case FIRE: //确定选择某个日期
                selectDate();
            break;
        }//当日期超出时没有切换到上个月或下个月
        if(newDay != curDay)
        {//日期改变后重绘界面
            curDay = newDay;
            repaint();
        }
    }
    //处理指针事件
    protected void pointerPressed(int x,int y)
    {//判断指针所点击的位置所属于的日期
        //第一步：判断是否在日期绘制的范围内
        if(x<startX || x>=startX + iCellWidth*7)
            return ;//不在绘制日期的范围内
        if(y< iCellHeight*2)
            return ;//不在绘制日期的范围内
        //第二步：计算点击的日期是当月的第几天
        calTemp.set(Calendar.YEAR, curYear);
        calTemp.set(Calendar.MONTH, curMonth);
        calTemp.set(Calendar.DAY_OF_MONTH,1);
        int index =1;
        index += ((y-iCellHeight*2)/iCellHeight) *7;
        index += (x - startX)/iCellWidth;
        index -= (calTemp.get(Calendar.DAY_OF_WEEK)-1);
        //第三步：判断是否在当月日期范围内
        int daysNum = getDaysOfMonth(curYear,curMonth);  //得到当月的天数
        if(index>0 && daysNum>= index)
        {
            curDay = index;
            repaint();
        }
    }
    //处理菜单命令事件
    public void commandAction(Command c, Displayable d)
    {
        if(c == nextYearCmd)//切换到下一年
        {
            curYear ++; 
            curMonth=0;
            notifyMonthChange();
        }
        else if(c == prevYearCmd)//切换到上一年
        {
            curYear --;
            curMonth=11;
            notifyMonthChange();
        }
        else if(c == nextMonthCmd)//切换到下一个月
            nextMonth();
        else if(c == prevMonthCmd)//切换到上一个月
            prevMonth();
        else if(c == selectCmd)
        {//确定选择某个日期
            selectDate();
        }
        repaint();
    }
    //绘制当前月的日历
    protected void paintMonth(Graphics g)
    {//绘制日历
        //第一布，显示当前年月
        int offsetY=0; //保存绘图的Y轴坐标
        g.setColor(clrSelectedFont);
        g.setFont(fontSelected);
        g.drawString(curYear+" / "+(curMonth+1),startX+iCellWidth*7/2,offsetY+2,Graphics.HCENTER | Graphics.TOP);
        //第二步，显示一周中每天的名称
        g.setColor(clrSelectedFont);
        g.setFont(fontSelected);
        offsetY+=iCellHeight;
        for(int i=0;i<7;i++)
            g.drawSubstring(weekDays,i*3,3,startX+i*iCellWidth+1,offsetY,Graphics.LEFT|Graphics.TOP);
        //第三步，显示当月所有日期
        calTemp.set(Calendar.YEAR, curYear);
        calTemp.set(Calendar.MONTH, curMonth);
        int dayOW=0; //保存星期
        int clr1,clr2; //保存颜色值
        Font ft; //保存字体
        int type =ImportDateFilter.NORMALDAY; //日期的类型
        int daysNum = getDaysOfMonth(curYear,curMonth);  //得到当月的天数
        offsetY+=iCellHeight;
        for(int i=1;i<=daysNum;i++)
        {//分别对每天进行绘制
            calTemp.set(Calendar.DAY_OF_MONTH,i);
            dayOW = calTemp.get(Calendar.DAY_OF_WEEK); //得到当天是星期几
            if(i==curDay)
            {//当天是被选中的日期，用固定的字体和颜色进行显示
                ft = fontSelected;
                clr1 = clrSelectedBk;
                clr2 = clrSelectedFont;
            }
            else
            {//对于未选中的日期通过日期类型决定显示方式
                if(dateFilter !=null)
                {//判断当天是否重要日期
                    type =dateFilter.isImportantDate(calTemp);
                }
                //type = i %4;
                ft = fontShow[type];
                clr1 = clrBk[type];
                clr2 = clrFont[type];
            }
            g.setFont(ft);
            g.setColor(clr1);
            g.fillRect(startX+(dayOW-1)*iCellWidth,offsetY,iCellWidth-1,iCellHeight-1);
            g.setColor(clr2);
            g.drawString(String.valueOf(i), startX+(dayOW-1)*iCellWidth+iCellWidth/2, offsetY+1, Graphics.HCENTER | Graphics.TOP);
            if(dayOW ==Calendar.SATURDAY)
                offsetY +=iCellHeight; // 转入下一周前增加Y轴坐标
        }
    }
    //将月份改为下一个月
    protected void nextMonth()
    {
        if(curMonth<11)
            curMonth ++;
        else
        {
            curMonth =0;
            curYear ++;
        }
        curDay = 1;
        notifyMonthChange();
    }
    //将月份改为上一个月
    protected void prevMonth()
    {
        if(curMonth>0)
            curMonth --;
        else
        {
            curMonth =11;
            curYear --;
        }
        curDay = 1;
        notifyMonthChange();
    }
    //月份变化通知
    protected void notifyMonthChange()
    {
        if(monthListener != null)
        {
            calTemp.set(Calendar.YEAR, curYear);
            calTemp.set(Calendar.MONTH, curMonth);
            calTemp.set(Calendar.DAY_OF_MONTH, curDay);
            monthListener.monthChanged(this,calTemp);
        }
    }
    //确定选择某个日期并引发事件
    protected void selectDate()
    {
        if(dateListener != null)
        {//引发事件
            calTemp.set(Calendar.YEAR, curYear);
            calTemp.set(Calendar.MONTH, curMonth);
            calTemp.set(Calendar.DAY_OF_MONTH, curDay);
            dateListener.dateSelected(this,calTemp);
        }
    }
    //得到某年某个月的天数
    protected int getDaysOfMonth(int year,int month)
    {
        if(month !=1)//如果不是2月，直接返回保存的当月天数
            return daysOfMonth[month];
        if(year%400==0 ||(year%100!=0 && year%4==0) )
            return 29;
        return daysOfMonth[month];
    }
}