如何在日历中显示下周的日期

Question

下面是显示当前日期的代码，现在我在代码中添加了两个新按钮 btnpreviousweek，btnnextweek我想在按钮上点击下周和上周的日期，我该怎么办？我如何更改日期以显示下周的日期或前一周的日期？此代码还显示从星期日到星期六的日期我只想显示星期一到星期五这是我的屏幕截图

public class MyCalendarActivity extends Activity implements OnClickListener {
    private static final String tag = "MyCalendarActivity";

    private TextView currentMonth;
    private ImageView prevMonth;
    private ImageView nextMonth;
    Button btnpreviousweek,btnnextweek;

    private GridView calendarView;
    private GridCellAdapter adapter;
    private Calendar _calendar;
    @SuppressLint("NewApi")
    private int month, year;
    private int actualYear, actualMonth, actualDay;
    @SuppressWarnings("unused")
    @SuppressLint({ "NewApi", "NewApi", "NewApi", "NewApi" })
    private final DateFormat dateFormatter = new DateFormat();
    private static final String dateTemplate = "MMMM yyyy";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.my_calendar_view);

        _calendar = Calendar.getInstance(Locale.getDefault());
        month = _calendar.get(Calendar.MONTH) + 1;
        year = _calendar.get(Calendar.YEAR);
        actualYear = year;
        actualMonth = month;
        actualDay = _calendar.get(Calendar.DAY_OF_MONTH);

        Log.d(tag, "Calendar Instance:= " + "Month: " + month + " " + "Year: "
                + year);

        btnpreviousweek = (Button) this.findViewById(R.id.btnpreviousweek);
        btnnextweek = (Button) this.findViewById(R.id.btnnextweek);

        btnpreviousweek.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
            //////////////////////////        what i write here         /////////////////////////
            }
        });

        btnnextweek.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                //////////////////////////        what i write here         /////////////////////////
            }
        });

        prevMonth = (ImageView) this.findViewById(R.id.prevMonth);
        prevMonth.setOnClickListener(this);

        currentMonth = (TextView) this.findViewById(R.id.currentMonth);
        currentMonth.setText(DateFormat.format(dateTemplate,
                _calendar.getTime()));

        nextMonth = (ImageView) this.findViewById(R.id.nextMonth);
        nextMonth.setOnClickListener(this);
        calendarView = (GridView) this.findViewById(R.id.calendar);

        adapter = new GridCellAdapter(getApplicationContext(),
                R.id.calendar_day_gridcell, month, year);
        adapter.notifyDataSetChanged();
        calendarView.setAdapter(adapter);
    }

    /**
     * 
     * @param month
     * @param year
     */
    private void setGridCellAdapterToDate(int month, int year) {
        adapter = new GridCellAdapter(getApplicationContext(),
                R.id.calendar_day_gridcell, month, year);
        _calendar.set(year, month - 1, _calendar.get(Calendar.DAY_OF_WEEK));
        currentMonth.setText(DateFormat.format(dateTemplate,
                _calendar.getTime()));
        adapter.notifyDataSetChanged();
        calendarView.setAdapter(adapter);
    }

    @Override
    public void onClick(View v) {
        if (v == prevMonth) {
            if (month <= 1) {
                month = 12;
                year--;
            } else {
                month--;
            }
            Log.d(tag, "Setting Prev Month in GridCellAdapter: " + "Month: "
                    + month + " Year: " + year);
            setGridCellAdapterToDate(month, year);
        }
        if (v == nextMonth) {
            if (month > 11) {
                month = 1;
                year++;
            } else {
                month++;
            }
            Log.d(tag, "Setting Next Month in GridCellAdapter: " + "Month: "
                    + month + " Year: " + year);
            setGridCellAdapterToDate(month, year);
        }

    }

    @Override
    public void onDestroy() {
        Log.d(tag, "Destroying View ...");
        super.onDestroy();
    }

    // Inner Class
    public class GridCellAdapter extends BaseAdapter implements OnClickListener {
        private static final String tag = "GridCellAdapter";
        private final Context _context;

        private final List<String> list;
        private static final int DAY_OFFSET = 1;
        private final String[] weekdays = new String[] { "Sun", "Mon", "Tue",
                "Wed", "Thu", "Fri", "Sat" };
        private final String[] months = { "January", "February", "March",
                "April", "May", "June", "July", "August", "September",
                "October", "November", "December" };
        private final int[] daysOfMonth = { 31, 28, 31, 30, 31, 30, 31, 31, 30,
                31, 30, 31 };
        private int daysInMonth;
        private int currentDayOfMonth;
        private int currentWeekDay;
        private Button gridcell;
        private TextView num_events_per_day;
        private final HashMap<String, Integer> eventsPerMonthMap;
        private final SimpleDateFormat dateFormatter = new SimpleDateFormat(
                "dd-MMM-yyyy");

        // Days in Current Month
        public GridCellAdapter(Context context, int textViewResourceId,
                int month, int year) {
            super();
            this._context = context;
            this.list = new ArrayList<String>();
            Log.d(tag, "==> Passed in Date FOR Month: " + month + " "
                    + "Year: " + year);
            Calendar calendar = Calendar.getInstance();
            setCurrentDayOfMonth(calendar.get(Calendar.DAY_OF_MONTH));

            setCurrentWeekDay(calendar.get(Calendar.DAY_OF_WEEK));

            Log.d(tag, "New Calendar:= " + calendar.getTime().toString());
            Log.d(tag, "CurrentDayOfWeek :" + getCurrentWeekDay());
            Log.d(tag, "CurrentDayOfMonth :" + getCurrentDayOfMonth());

            // Print Month
            printMonth(month, year);

            // Find Number of Events
            eventsPerMonthMap = findNumberOfEventsPerMonth(year, month);
        }

        private String getMonthAsString(int i) {
            return months[i];
        }

        private String getWeekDayAsString(int i) {
            return weekdays[i];
        }

        private int getNumberOfDaysOfMonth(int i) {
            return daysOfMonth[i];
        }

        public String getItem(int position) {
            return list.get(position);
        }

        @Override
        public int getCount() {
            return list.size();
        }

        /**
         * Prints Month
         * 
         * @param mm
         * @param yy
         */
        private void printMonth(int mm, int yy) {
            Log.d(tag, "==> printMonth: mm: " + mm + " " + "yy: " + yy);
            int trailingSpaces = 0;
            int daysInPrevMonth = 0;

            int currentMonth = mm - 1;
            String currentMonthName = getMonthAsString(currentMonth);
            daysInMonth = getNumberOfDaysOfMonth(currentMonth);

            Log.d(tag, "Current Month: " + " " + currentMonthName + " having " +  
                daysInMonth + " days.");

            GregorianCalendar cal = new GregorianCalendar(yy, currentMonth, 
                    getCurrentDayOfMonth());
            Log.d(tag, "Gregorian Calendar:= " + cal.getTime().toString());

            int currentWeekDay = cal.get(Calendar.DAY_OF_WEEK) - 1;
            trailingSpaces = currentWeekDay;

            Log.d(tag, "Week Day:" + currentWeekDay + " is " + 
                    getWeekDayAsString(currentWeekDay));
            Log.d(tag, "No. Trailing space to Add: " + trailingSpaces);
            Log.d(tag, "No. of Days in Previous Month: " + daysInPrevMonth);

            if (cal.isLeapYear(cal.get(Calendar.YEAR)))
                if (mm == 2) ++daysInMonth;
                else if (mm == 3)
                    ++daysInPrevMonth;

            // move at the begging of the week
            int i = getCurrentDayOfMonth();
            int j = currentWeekDay;
            while (i > 1 && j > 0) {
                i--;
                j--;
            }
            // print the week, starting at Sunday
            for (j = 0; i <= daysInMonth && j < 7; i++, j++) {
                Log.d(currentMonthName, String.valueOf(i) + " " + 
                        getMonthAsString(currentMonth) + " " + yy);
                // If it is the current date, printing in BLUE (Orange)
                if (i == actualDay && mm == actualMonth && yy == actualYear) {
                    list.add(String.valueOf(i) + "-BLUE" + "-" + 
                            getMonthAsString(currentMonth) + "-" + yy);
                } else {
                    list.add(String.valueOf(i) + "-WHITE" + "-" + 
                            getMonthAsString(currentMonth) + "-" + yy);
                }
            }
        }

        /**
         * NOTE: YOU NEED TO IMPLEMENT THIS PART Given the YEAR, MONTH, retrieve
         * ALL entries from a SQLite database for that month. Iterate over the
         * List of All entries, and get the dateCreated, which is converted into
         * day.
         * 
         * @param year
         * @param month
         * @return
         */
        private HashMap<String, Integer> findNumberOfEventsPerMonth(int year,
                int month) {
            HashMap<String, Integer> map = new HashMap<String, Integer>();

            return map;
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View row = convertView;
            if (row == null) {
                LayoutInflater inflater = (LayoutInflater) _context
                        .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                row = inflater.inflate(R.layout.screen_gridcell, parent, 
                        false);
            }

            // Get a reference to the Day gridcell
            gridcell = (Button) row.findViewById(R.id.calendar_day_gridcell);
            gridcell.setOnClickListener(this);

            // ACCOUNT FOR SPACING

            Log.d(tag, "Current Day: " + getCurrentDayOfMonth());
            String[] day_color = list.get(position).split("-");
            String theday = day_color[0];
            String themonth = day_color[2];
            String theyear = day_color[3];
            if ((!eventsPerMonthMap.isEmpty()) && (eventsPerMonthMap != null))  {
                if (eventsPerMonthMap.containsKey(theday)) {
                    num_events_per_day = (TextView) row
                            .findViewById(R.id.num_events_per_day);
                    Integer numEvents = (Integer) eventsPerMonthMap.get(theday);
                    num_events_per_day.setText(numEvents.toString());
                }
            }

            // Set the Day GridCell
            gridcell.setText(theday);
            gridcell.setTag(theday + "-" + themonth + "-" + theyear);
            Log.d(tag, "Setting GridCell " + theday + "-" + themonth + "-"
                    + theyear);

            if (day_color[1].equals("GREY")) {
                gridcell.setTextColor(getResources()
                        .getColor(R.color.lightgray));
            }
            if (day_color[1].equals("WHITE")) {
                gridcell.setTextColor(getResources().getColor(
                        R.color.lightgray02));
            }
            if (day_color[1].equals("BLUE")) {
                gridcell.setText("(" + theday + ")");

                gridcell.setTextColor(getResources().getColor(R.color.orrange));
            }
            return row;
        }

        @Override
        public void onClick(View view) {
            String date_month_year = (String) view.getTag();
            //    selectedDayMonthYearButton.setText("Selected: " + date_month_year);
            Log.e("Selected date", date_month_year);
            try {
                Date parsedDate = dateFormatter.parse(date_month_year);
                Log.d(tag, "Parsed Date: " + parsedDate.toString());

            } catch (ParseException e) {
                e.printStackTrace();
            }
        }

        public int getCurrentDayOfMonth() {
            return currentDayOfMonth;
        }

        private void setCurrentDayOfMonth(int currentDayOfMonth) {
            this.currentDayOfMonth = currentDayOfMonth;
        }

        public void setCurrentWeekDay(int currentWeekDay) {
            this.currentWeekDay = currentWeekDay;
        }

        public int getCurrentWeekDay() {
            return currentWeekDay;
        }
    }
}

Answer 1

此代码可能对您有所帮助，

 Calendar cal = GregorianCalendar.getInstance();
    cal.setTime(new Date());
    cal.add(Calendar.DAY_OF_YEAR, -k);
    Date daysBeforeDate = cal.getTime();
    String start_dt1 = "" + daysBeforeDate;

你可以用数字7替换k，这样就可以得到七天之前的日期，就像你可以在k天之后使用k而不是-k作为日期。