android - 如何在日历中显示上个月的日期

Question

这是我下面的 cCalender 代码可以正常工作，但唯一的问题是不显示日期之前的第一天看到这个http://imgur.com/inl1GzE和一个月的最后一天之后完整的源代码在这里 https://www.zeta -uploader.com/1699876023

              i want to do something like this

           Sun Mon Tues  Wed  Thur Fri  Sat 
            29  30  31   1      2   3    4


        public class HoyahCalendar extends Activity {
public static int mYear;
public static int currentIndex = -1;
public static int mMonth;
public static int mDay;
public static String[][] a = new String[6][7];


        Calendar mCalendar = Calendar.getInstance();
    mYear = mCalendar.get(Calendar.YEAR);
    mMonth = mCalendar.get(Calendar.MONTH) + 1;
    mDay = mCalendar.get(Calendar.DAY_OF_MONTH);




                  last_week.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            if (mMonth == 1) {
                mYear -= 1;
                mMonth = 12;
                new ShowCalendar(mYear, mMonth, mDay, "last");
                showOnScreen();
            } else {
                // mMonth -= 1;
                new ShowCalendar(mYear, mMonth, mDay, "last");
                showOnScreen();
            }
        }
    });

    next_week.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {

            if (mMonth == 12) {
                mYear += 1;
                mMonth = 1;
                new ShowCalendar(mYear, mMonth, mDay, "next");
                showOnScreen();
            } else {
                if (HoyahCalendar.currentIndex == 4) {
                    HoyahCalendar.currentIndex = 4;
                    // mMonth += 1;
                }

                new ShowCalendar(mYear, mMonth, mDay, "next");
                showOnScreen();
            }

        }
    });

    new ShowCalendar(mYear, mMonth);
    showOnScreen();





                  public class ShowCalendar {
int mYear;
int mMonth;
int mDay;
public ShowCalendar(int mYear, int mMonth){
    this.mYear = mYear;
    this.mMonth = mMonth;
    calculateMonthFirstday();
}
public ShowCalendar(int mYear, int mMonth, int mDay){
    this.mYear = mYear;
    this.mMonth = mMonth;
    HoyahCalendar.currentIndex = 0;

    this.mDay = mDay;
    calculateMonthFirstday();
}


public int getmDay() {
    return mDay;
}





public void setmDay(int mDay) {
    this.mDay = mDay;
}





public ShowCalendar(int mYear, int mMonth, int mDay, String time){
    this.mYear = mYear;
    this.mMonth = mMonth;
    if (time == "next"){
        HoyahCalendar.currentIndex++;
        if (HoyahCalendar.currentIndex == 5){
            HoyahCalendar.currentIndex--;
        }
        this.mDay = mDay + 7;
    } else if (time == "last"){
        HoyahCalendar.currentIndex--;
        if (HoyahCalendar.currentIndex == -1){
            HoyahCalendar.currentIndex++;
        }
        this.mDay = mDay - 7;
    }
    calculateMonthFirstday();
}

public void calculateMonthFirstday(){
    int month, first_day=0;
    if((mYear%4==0 && mYear%100!=0)||(mYear%400==0))
        month=1;
    else
        month=0;

    int y, y12, c, c12, m, d;
    y = mYear%100;
    y12 = (mYear-1)%100; //only for January and February
    c = mYear/100;
    c12 = (mYear-1)/100;
    m = mMonth;
    d = 1;

    switch(mMonth){
    case 1: {first_day = y12 + y12/4 +c12/4 - 2*c12 + 26*(13 + 1)/10 + d - 1;break;}
    case 2: {first_day = y12 + y12/4 +c12/4 - 2*c12 + 26*(14 + 1)/10 + d - 1;break;}
    case 3: {first_day = y + y/4 +c/4 - 2*c + 26*(m + 1)/10 + d - 1;break;}
    case 4: {first_day = y + y/4 +c/4 - 2*c + 26*(m + 1)/10 + d - 1;break;}
    case 5: {first_day = y + y/4 +c/4 - 2*c + 26*(m + 1)/10 + d - 1;break;}
    case 6: {first_day = y + y/4 +c/4 - 2*c + 26*(m + 1)/10 + d - 1;break;}
    case 7: {first_day = y + y/4 +c/4 - 2*c + 26*(m + 1)/10 + d - 1;break;}
    case 8: {first_day = y + y/4 +c/4 - 2*c + 26*(m + 1)/10 + d - 1;break;}
    case 9: {first_day = y + y/4 +c/4 - 2*c + 26*(m + 1)/10 + d - 1;break;}
    case 10: {first_day = y + y/4 +c/4 - 2*c + 26*(m + 1)/10 + d - 1;break;}
    case 11: {first_day = y + y/4 +c/4 - 2*c + 26*(m + 1)/10 + d - 1;break;}
    case 12: {first_day = y + y/4 +c/4 - 2*c + 26*(m + 1)/10 + d - 1;break;}
    }
    if(first_day<0)
        first_day = 7 - (Math.abs(first_day))%7;//first_day每月第一天星期几
    else
        first_day = first_day%7;

    switch(mMonth){
        case 1: {CalculateCalendar(1,first_day,31);break;}
        case 2: {CalculateCalendar(2,first_day,28+month);break;}
        case 3: {CalculateCalendar(3,first_day,31);break;}
        case 4: {CalculateCalendar(4,first_day,30);break;}
        case 5: {CalculateCalendar(5,first_day,31);break;}
        case 6: {CalculateCalendar(6,first_day,30);break;}
        case 7: {CalculateCalendar(7,first_day,31);break;}
        case 8: {CalculateCalendar(8,first_day,31);break;}
        case 9: {CalculateCalendar(9,first_day,30);break;}
        case 10:{CalculateCalendar(10,first_day,31);break;}
        case 11:{CalculateCalendar(11,first_day,30);break;}
        case 12:{CalculateCalendar(12,first_day,31);break;}
    }
}

public void CalculateCalendar(int month_no, int week_no, int month_days){

    int i, s = 0;
    int currentDay;
    if (this.mDay == 0){
        mDay = 1;
        currentDay= HoyahCalendar.mDay;     
    }else {
        currentDay = this.mDay;
    }
    //String[][] a = new String[6][7];
    for (i=0;i<week_no;i++)

        HoyahCalendar.a[i/7][i%7] = "";

    for(i=week_no; i<week_no + month_days; i++){
        s = i - week_no + 1;
        HoyahCalendar.a[i/7][i%7] = String.valueOf(s);
        if (s == currentDay && HoyahCalendar.currentIndex == -1){
            HoyahCalendar.currentIndex = i/7;
        }
    } 
    for (i=0; i<7;i++){
        if (HoyahCalendar.a[HoyahCalendar.currentIndex][i] == null){
            HoyahCalendar.a[0][i] = "";
        }else{
            HoyahCalendar.a[0][i] = 
     HoyahCalendar.a[HoyahCalendar.currentIndex][i];
        }

    }
    for(i=week_no+month_days; i<42; i++)


        HoyahCalendar.a[i/7][i%7] = "";
}
   }

Answer 1

这是您的问题的解决方案。首先，您需要对将月历计算为 6x7 数组的函数进行不同的设计，因此使用这个以年和月为参数的函数，然后它将生成一个准确的月历数组。

/**
 * 
 * @param year the year
 * @param month January=0, Feb = 1, ...., Nov = 10, and Dec = 11, you know what I mean
 * @return
 */
private static int[][] getArrayCalendar(int year,int month)
{
    //VERY IMPORTANT
    //SUN = 1, MON = 2, TU = 3, ..., Fri = 6, Sat = 7 according to USA
    int[][] a = new int[6][7];
    int day = 1; //day must be always one
    Calendar cal = Calendar.getInstance();
    cal.set(Calendar.YEAR, year);
    cal.set(Calendar.MONTH, month);
    cal.set(Calendar.DAY_OF_MONTH, day);

    int dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
    int goBack = 1 - dayOfWeek;
    cal.add(Calendar.DAY_OF_MONTH, goBack);


    System.out.println("SU\tMO\tTU\tWE\tTH\tFR\tSA");

    for(int i=0;i<a.length;i++)
    {
        for(int j=0;j<a[0].length;j++)
        {
            a[i][j] = cal.get(Calendar.DAY_OF_MONTH);
            System.out.print(cal.get(Calendar.DAY_OF_MONTH));
            System.out.print("\t");
            cal.add(Calendar.DAY_OF_MONTH, 1);
        }
        System.out.println();
    }

    return a;
}

示例：getArrayCalendar(2013,4)// May=4 , year= 2013 RESULT AS PRINTED:

SU  MO  TU  WE  TH  FR  SA
28  29  30  1   2   3   4
5   6   7   8   9   10  11  
12  13  14  15  16  17  18  
19  20  21  22  23  24  25  
26  27  28  29  30  31  1   
2   3   4   5   6   7   8

- 现在快速解决这个问题：修改你的 ShowCalendar 类如下：

    package com.example.calender5example;

    import java.util.Calendar;

    public class ShowCalendar
    {

          int mYear;
        int mMonth;
        int mDay;

    public ShowCalendar(int mYear, int mMonth)
    {
        this.mYear = mYear;
        this.mMonth = mMonth;
        calculateMonthFirstday();
    }

    public ShowCalendar(int mYear, int mMonth, int mDay)
    {
        this.mYear = mYear;
        this.mMonth = mMonth;
        HoyahCalendar.currentIndex = 0;

        this.mDay = mDay;
        calculateMonthFirstday();
    }

    public int getmDay()
    {
        return mDay;
    }

    public void setmDay(int mDay)
    {
        this.mDay = mDay;
    }

    public ShowCalendar(int mYear, int mMonth, int mDay, String time)
    {
        this.mYear = mYear;
        this.mMonth = mMonth;
        if (time == "next")
        {
            HoyahCalendar.currentIndex++;
            if (HoyahCalendar.currentIndex == 5)
            {
                HoyahCalendar.currentIndex--;
            }
            this.mDay = mDay + 7;
        }
        else if (time == "last")
        {
            HoyahCalendar.currentIndex--;
            if (HoyahCalendar.currentIndex == -1)
            {
                HoyahCalendar.currentIndex++;
            }
            this.mDay = mDay - 7;
        }
        calculateMonthFirstday();
    }

    public void calculateMonthFirstday()
    {
        int month, first_day = 0;
        if ((mYear % 4 == 0 && mYear % 100 != 0) || (mYear % 400 == 0))
            month = 1;
        else
            month = 0;

        int y, y12, c, c12, m, d;
        y = mYear % 100;
        y12 = (mYear - 1) % 100; // only for January and February
        c = mYear / 100;
        c12 = (mYear - 1) / 100;
        m = mMonth;
        d = 1;

        switch (mMonth)
        {
        case 1:
        {
            first_day = y12 + y12 / 4 + c12 / 4 - 2 * c12 + 26 * (13 + 1) / 10 + d - 1;
            break;
        }
        case 2:
        {
            first_day = y12 + y12 / 4 + c12 / 4 - 2 * c12 + 26 * (14 + 1) / 10 + d - 1;
            break;
        }
        case 3:
        {
            first_day = y + y / 4 + c / 4 - 2 * c + 26 * (m + 1) / 10 + d - 1;
            break;
        }
        case 4:
        {
            first_day = y + y / 4 + c / 4 - 2 * c + 26 * (m + 1) / 10 + d - 1;
            break;
        }
        case 5:
        {
            first_day = y + y / 4 + c / 4 - 2 * c + 26 * (m + 1) / 10 + d - 1;
            break;
        }
        case 6:
        {
            first_day = y + y / 4 + c / 4 - 2 * c + 26 * (m + 1) / 10 + d - 1;
            break;
        }
        case 7:
        {
            first_day = y + y / 4 + c / 4 - 2 * c + 26 * (m + 1) / 10 + d - 1;
            break;
        }
        case 8:
        {
            first_day = y + y / 4 + c / 4 - 2 * c + 26 * (m + 1) / 10 + d - 1;
            break;
        }
        case 9:
        {
            first_day = y + y / 4 + c / 4 - 2 * c + 26 * (m + 1) / 10 + d - 1;
            break;
        }
        case 10:
        {
            first_day = y + y / 4 + c / 4 - 2 * c + 26 * (m + 1) / 10 + d - 1;
            break;
        }
        case 11:
        {
            first_day = y + y / 4 + c / 4 - 2 * c + 26 * (m + 1) / 10 + d - 1;
            break;
        }
        case 12:
        {
            first_day = y + y / 4 + c / 4 - 2 * c + 26 * (m + 1) / 10 + d - 1;
            break;
        }
        }
        if (first_day < 0)
            first_day = 7 - (Math.abs(first_day)) % 7;// first_day每月第一天星期几
        else
            first_day = first_day % 7;

        switch (mMonth)
        {
        case 1:
        {
            CalculateCalendar(1, first_day, 31);
            break;
        }
        case 2:
        {
            CalculateCalendar(2, first_day, 28 + month);
            break;
        }
        case 3:
        {
            CalculateCalendar(3, first_day, 31);
            break;
        }
        case 4:
        {
            CalculateCalendar(4, first_day, 30);
            break;
        }
        case 5:
        {
            CalculateCalendar(5, first_day, 31);
            break;
        }
        case 6:
        {
            CalculateCalendar(6, first_day, 30);
            break;
        }
        case 7:
        {
            CalculateCalendar(7, first_day, 31);
            break;
        }
        case 8:
        {
            CalculateCalendar(8, first_day, 31);
            break;
        }
        case 9:
        {
            CalculateCalendar(9, first_day, 30);
            break;
        }
        case 10:
        {
            CalculateCalendar(10, first_day, 31);
            break;
        }
        case 11:
        {
            CalculateCalendar(11, first_day, 30);
            break;
        }
        case 12:
        {
            CalculateCalendar(12, first_day, 31);
            break;
        }
        }
    }

    public void CalculateCalendar(int month_no, int week_no, int month_days)
    {

        int i, s = 0;
        int currentDay;
        if (this.mDay == 0)
        {
            mDay = 1;
            currentDay = HoyahCalendar.mDay;
        }
        else
        {
            currentDay = this.mDay;
        }
        // String[][] a = new String[6][7];
        for (i = 0; i < week_no; i++)

            HoyahCalendar.a[i / 7][i % 7] = "";

        for (i = week_no; i < week_no + month_days; i++)
        {
            s = i - week_no + 1;
            HoyahCalendar.a[i / 7][i % 7] = String.valueOf(s);
            if (s == currentDay && HoyahCalendar.currentIndex == -1)
            {
                HoyahCalendar.currentIndex = i / 7;
            }
        }
        for (i = 0; i < 7; i++)
        {
            if (HoyahCalendar.a[HoyahCalendar.currentIndex][i] == null)
            {
                HoyahCalendar.a[0][i] = "";
            }
            else
            {
                HoyahCalendar.a[0][i] = HoyahCalendar.a[HoyahCalendar.currentIndex][i];
            }

        }
        for (i = week_no + month_days; i < 42; i++)

            HoyahCalendar.a[i / 7][i % 7] = "";
//my fix starts here, I don't want to miss with your code

        int a[][] = getArrayCalendar(mYear, mMonth);
        HoyahCalendar.a = toStringArray(a);// Here I replaced your array
    }

    private String[][] toStringArray(int[][] a)
    {
        String[][] array = new String[6][7];
        for (int i = 0; i < a.length; i++)
        {
            for (int j = 0; j < a[0].length; j++)
            {
                array[i][j] = Integer.toString(a[i][j]);
            }
            System.out.println();
        }
        return array;
    }

    /**
     * 
     * @param year
     *            the year
     * @param month
     *            January=0, Feb = 1, ...., Nov = 10, and Dec = 11, you know
     *            what I mean
     * @return
     */
    private static int[][] getArrayCalendar(int year, int month)
    {
        // VERY IMPORTANT
        // SUN = 1, MON = 2, TU = 3, ..., Fri = 6, Sat = 7 according to USA
        int[][] a = new int[6][7];
        int day = 1; // day must be always one
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, year);
        cal.set(Calendar.MONTH, month);
        cal.set(Calendar.DAY_OF_MONTH, day);

        int dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
        int goBack = 1 - dayOfWeek;
        cal.add(Calendar.DAY_OF_MONTH, goBack);

        System.out.println("SU\tMO\tTU\tWE\tTH\tFR\tSA");

        for (int i = 0; i < a.length; i++)
        {
            for (int j = 0; j < a[0].length; j++)
            {
                a[i][j] = cal.get(Calendar.DAY_OF_MONTH);
                System.out.print(cal.get(Calendar.DAY_OF_MONTH));
                System.out.print("\t");
                cal.add(Calendar.DAY_OF_MONTH, 1);
            }
            System.out.println();
        }

        return a;
    }
}

现在您可以使用该功能为任何（年、月）生成完整的月历，并使用它来浏览您的 UI。