其实只要把 Calandar这个类熟悉了之后，都好写了。在学校的时候老师教过一次的是从1900年开始算的那种，当时还花费好多时间在这个上面，花了很多时间之后，才发现自己是如此愚蠢
先说下我的思路
1.确定要的行数
我见过有些的是5行，有些是6行。当然列数肯定都是7列（毕竟是一周7天嘛），这样返回的数据大小为row*7
2.计算当前显示月的上一月份日期
把日期设置为当月的第一天calendar.set(Calendar.DAY_OF_MONTH, 1);
获取本月第一天的星期数int firstDayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
将日期设置为上个月要开始的时间（后面我会说为什么要这样减）calendar.setTimeInMillis(calendar.getTimeInMillis()-firstDayOfWeek * oneDayTime);
从本月第一天的星期数开始循环递减，直到firstDayOfWeek不大于一为止，这里的数据就是上月份的
3.计算当前月份的日期
把日期设置为当月的第一天calendar.set(Calendar.DAY_OF_MONTH, 1);
获取本月最大的日期int maxDateOfMonth = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
从一开始循环到最大日期数就是本月的日期数据了
4.计算下个月份的日期
将日期设置为本月最大的那一天calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
循环获取下月的日期数据，row*7 - 上月+本月的数据.size()就是本次递加要获取的数据
关于上月份为什么要那样减请看下图
日历.jpg
以下是所有代码,欢迎指出问题，欢迎技术交流讨论
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;
/**
* Created by cynthia on 2018/4/15.
*/
public class CalendarUtils<T> {
private SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd", Locale.CHINESE);
private long oneDayTime = 24 * 60 * 60 * 1000;//一天的时间戳
/**
* @param date 生成月份 （yyyy-MM-dd）
* @param row 日期总共几行，有些日历是只有5行，window7的日历是6行,列数应当永远为7
* @return list
*/
public List<CalendarEntity<T>> genDate(String date, int row) {
List<CalendarEntity<T>> dateList = new ArrayList<>();
int dateListSize = row * 7;
Date paramDate;
try {
paramDate = dateFormat.parse(date);
Calendar calendar = Calendar.getInstance();
calendar.clear();
calendar.setTime(paramDate);
calendar.set(Calendar.DAY_OF_MONTH, 1);//设置日期从传入月第一天开始
int firstDayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);//本月第一天是周几
calendar.setTimeInMillis(calendar.getTimeInMillis()-firstDayOfWeek * oneDayTime);
//将上个月的日期计算出来
for (int i = firstDayOfWeek; i > 1; i--) {
long timeLong = calendar.getTimeInMillis();
calendar.clear();
calendar.setTimeInMillis(timeLong + oneDayTime);
dateList.add(new CalendarEntity<T>(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH) + 1,
calendar.get(Calendar.DAY_OF_WEEK), calendar.get(Calendar.DAY_OF_MONTH), dateFormat.format(calendar.getTime()),
calendar.getTimeInMillis(), CalendarEntity.lastMonth));
}
//将传入的月份数据计算出来
calendar.clear();
calendar.setTime(paramDate);
calendar.set(Calendar.DAY_OF_MONTH, 1);//设置日期从传入月第一天开始
//获得本月最大的日期
int maxDateOfMonth = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
dateList.add(new CalendarEntity<T>(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH) + 1,
calendar.get(Calendar.DAY_OF_WEEK), calendar.get(Calendar.DAY_OF_MONTH), dateFormat.format(calendar.getTime()),
calendar.getTimeInMillis(), CalendarEntity.nowMonth));
for (int i = 1; i < maxDateOfMonth; i++) {
long timeLong = calendar.getTimeInMillis();
calendar.clear();
calendar.setTimeInMillis(timeLong + oneDayTime);
dateList.add(new CalendarEntity<T>(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH) + 1,
calendar.get(Calendar.DAY_OF_WEEK), calendar.get(Calendar.DAY_OF_MONTH), dateFormat.format(calendar.getTime()),
calendar.getTimeInMillis(), CalendarEntity.nowMonth));
}
calendar.clear();
calendar.setTime(paramDate);
calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));//设置日期从传入月最后一天开始
//获取下月的日期数据
for (int i = dateList.size(); i < dateListSize; i++) {
long timeLong = calendar.getTimeInMillis();
calendar.clear();
calendar.setTimeInMillis(timeLong + oneDayTime);
dateList.add(new CalendarEntity<T>(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH) + 1,
calendar.get(Calendar.DAY_OF_WEEK), calendar.get(Calendar.DAY_OF_MONTH), dateFormat.format(calendar.getTime()),
calendar.getTimeInMillis(), CalendarEntity.nextMonth));
}
} catch (ParseException e) {
e.printStackTrace();
}
return dateList;
}
}
CalendarEntity.java
import java.io.Serializable;
/**
* Created by cynthia on 2018/4/15.
*/
public class CalendarEntity<T> implements Serializable {
public static final int nowMonth = 1;//本月
public static final int lastMonth = 2;//上个月
public static final int nextMonth = 3;//下个月
private int year;
private int month;
private int week;
private int day;
private String dateStr;//yyyy-MM-dd
private T data; //外部数据类型
private long time;//时间戳
private int dateType;//日期类型
public int getDay() {
return day;
}
public int getMonth() {
return month;
}
public int getWeek() {
return week;
}
public int getDateType() {
return dateType;
}
public void setDateType(int dateType) {
this.dateType = dateType;
}
public int getYear() {
return year;
}
public long getTime() {
return time;
}
public String getDateStr() {
return dateStr;
}
public void setDateStr(String dateStr) {
this.dateStr = dateStr;
}
public void setDay(int day) {
this.day = day;
}
public void setMonth(int month) {
this.month = month;
}
public void setTime(long time) {
this.time = time;
}
public void setWeek(int week) {
this.week = week;
}
public void setYear(int year) {
this.year = year;
}
public CalendarEntity() {
}
public CalendarEntity(int year, int month, int week, int day, String dateStr, long time, int dateType) {
this.year = year;
this.month = month;
this.week = week;
this.day = day;
this.dateStr = dateStr;
this.time = time;
this.dateType = dateType;
}
public T getData() {
return data;
}
public void setData(T data) {
this.data = data;
}
}
数据源有了，什么样的ui都好调了，之前在网上看的demo 都是画布画的ui 感觉特别麻烦，我还是默默的选择了xml布局
