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/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.util;
import java.util.Calendar;
/**
* Helps answer common questions that come up when displaying a month in a
* 6 row calendar grid format.
*
* Not thread safe.
*/
public class MonthDisplayHelper {
// display pref
private final int mWeekStartDay;
// holds current month, year, helps compute display
private Calendar mCalendar;
// cached computed stuff that helps with display
private int mNumDaysInMonth;
private int mNumDaysInPrevMonth;
private int mOffset;
/**
* @param year The year.
* @param month The month.
* @param weekStartDay What day of the week the week should start.
*/
public MonthDisplayHelper(int year, int month, int weekStartDay) {
if (weekStartDay < Calendar.SUNDAY || weekStartDay > Calendar.SATURDAY) {
throw new IllegalArgumentException();
}
mWeekStartDay = weekStartDay;
mCalendar = Calendar.getInstance();
mCalendar.set(Calendar.YEAR, year);
mCalendar.set(Calendar.MONTH, month);
mCalendar.set(Calendar.DAY_OF_MONTH, 1);
mCalendar.set(Calendar.HOUR_OF_DAY, 0);
mCalendar.set(Calendar.MINUTE, 0);
mCalendar.set(Calendar.SECOND, 0);
mCalendar.getTimeInMillis();
recalculate();
}
public MonthDisplayHelper(int year, int month) {
this(year, month, Calendar.SUNDAY);
}
public int getYear() {
return mCalendar.get(Calendar.YEAR);
}
public int getMonth() {
return mCalendar.get(Calendar.MONTH);
}
public int getWeekStartDay() {
return mWeekStartDay;
}
/**
* @return The first day of the month using a constants such as
* {@link java.util.Calendar#SUNDAY}.
*/
public int getFirstDayOfMonth() {
return mCalendar.get(Calendar.DAY_OF_WEEK);
}
/**
* @return The number of days in the month.
*/
public int getNumberOfDaysInMonth() {
return mNumDaysInMonth;
}
/**
* @return The offset from displaying everything starting on the very first
* box. For example, if the calendar is set to display the first day of
* the week as Sunday, and the month starts on a Wednesday, the offset is 3.
*/
public int getOffset() {
return mOffset;
}
/**
* @param row Which row (0-5).
* @return the digits of the month to display in one
* of the 6 rows of a calendar month display.
*/
public int[] getDigitsForRow(int row) {
if (row < 0 || row > 5) {
throw new IllegalArgumentException("row " + row
+ " out of range (0-5)");
}
int [] result = new int[7];
for (int column = 0; column < 7; column++) {
result[column] = getDayAt(row, column);
}
return result;
}
/**
* @param row The row, 0-5, starting from the top.
* @param column The column, 0-6, starting from the left.
* @return The day at a particular row, column
*/
public int getDayAt(int row, int column) {
if (row == 0 && column < mOffset) {
return mNumDaysInPrevMonth + column - mOffset + 1;
}
int day = 7 * row + column - mOffset + 1;
return (day > mNumDaysInMonth) ?
day - mNumDaysInMonth : day;
}
/**
* @return Which row day is in.
*/
public int getRowOf(int day) {
return (day + mOffset - 1) / 7;
}
/**
* @return Which column day is in.
*/
public int getColumnOf(int day) {
return (day + mOffset - 1) % 7;
}
/**
* Decrement the month.
*/
public void previousMonth() {
mCalendar.add(Calendar.MONTH, -1);
recalculate();
}
/**
* Increment the month.
*/
public void nextMonth() {
mCalendar.add(Calendar.MONTH, 1);
recalculate();
}
/**
* @return Whether the row and column fall within the month.
*/
public boolean isWithinCurrentMonth(int row, int column) {
if (row < 0 || column < 0 || row > 5 || column > 6) {
return false;
}
if (row == 0 && column < mOffset) {
return false;
}
int day = 7 * row + column - mOffset + 1;
if (day > mNumDaysInMonth) {
return false;
}
return true;
}
// helper method that recalculates cached values based on current month / year
private void recalculate() {
mNumDaysInMonth = mCalendar.getActualMaximum(Calendar.DAY_OF_MONTH);
mCalendar.add(Calendar.MONTH, -1);
mNumDaysInPrevMonth = mCalendar.getActualMaximum(Calendar.DAY_OF_MONTH);
mCalendar.add(Calendar.MONTH, 1);
int firstDayOfMonth = getFirstDayOfMonth();
int offset = firstDayOfMonth - mWeekStartDay;
if (offset < 0) {
offset += 7;
}
mOffset = offset;
}
}
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