I am making an event calendar in Java and am having issues with a "Java.lang.ArrayIndexOutOfBoundsException" bug.
It usually pops up whenever I enter a date and press the "n" or "p" command a few times.
Appologies if the code below is messy.
thank you
import java.io.File; import java.io.FileNotFoundException; import java.io.OutputStream; import java.io.PrintStream; import java.util.Calendar; import java.util.Scanner; import java.util.*; import java.io.*;
public class Assignment2 {
// sets the width of each cell in the calendar private static int SIZE = 15; private static char HORIZONTAL = '='; private static char VERTICAL = '|'; private static boolean showLine = true;// to show the string date and month // at end private static String days[] = {"Sun", "Mon", "Tue", "Wed", "Thur", "Fri", "Sat"}; // static value, will be set to find the user specified date.. otherwise will remain -1. private static int dayValue = -1;
private static String[][] eventArray; public static boolean loadEventsFromFile(String filename) {
eventArray = new String[12][]; for(int i = 0; i < 12; i++) eventArray[i] = new String[getMaximumDays(i)];
try { Scanner input = new Scanner(new File(filename)); while(input.hasNext()) { String date = input.next(); String event = input.nextLine().trim(); int day = dayFromDate(date); int month = monthFromDate(date); eventArray[month-1][day-1] = event; } input.close(); return true;
} catch (FileNotFoundException e) { //nothing to do if file does not exist return false; } }
public static void drawMonth(PrintStream out, int month, int daysToSkip, int maxDays) { // calculate the near center where to display month number int center = SIZE * 3; String space = " ";
// display blanks upto center for (int i = 0; i < center; i++) out.print(space); // now display month number out.print(month + " "); // print week days for(int i=0; i will repeat for each // cell int day = start; String space = " "; out.print("|"); for (int cell = 1; cell <= 7; cell++) { str = ""; if (cell > skip && day <= maxDaysInMonth) { if(dayValue == day) { str += "*" + day++ + "*"; } else { str += day++; } } // pad it with extra spaces to match SIZE while (str.length() < SIZE - 1) str += space; str += VERTICAL; out.print(str); } // now remaining lines will be similar to above but the day number is // not there... only spaces padded to match cell SIZE // the pattern for each cell is int height = SIZE / 2; day = start; for (int h = 2 ; h <= height; h++) { out.print(" |"); for (int cell = 1; cell <= 7; cell++, day++) { str = ""; if(h == 2 && cell > skip && day <= maxDaysInMonth && eventArray[month-1][day-1] != null) str = eventArray[month-1][day-1]; while (str.length() < SIZE - 1) str += space; str += VERTICAL; out.print(str); } } out.print(" "); } public static void displayDate(PrintStream out,int month, int day) { if (showLine == true) { out.println("Month: " + month); out.println("Day: " + day); } } public static int monthFromDate(String date) { // split the date into 2 based on / delimiter String tokens[] = date.split("/"); // convert 1st token and return as month return Integer.parseInt(tokens[0]); } public static int dayFromDate(String date) { // split the date into 2 based on / delimiter String tokens[] = date.split("/"); // convert 2nd token and return as day return Integer.parseInt(tokens[1]); } public static void drawCalendar(PrintStream out, int month, int day) { int startingDay = getStartingDay(month); int maxDays = getMaximumDays(month); drawMonth(out, month, startingDay, maxDays); displayDate(out, month, day); } // method to correctly return the next month public static int nextGoodMonth(int month) { int mt = month; if (month == 12) return 1; return mt + 1; } // method to correctly return the previous month public static int previousGoodMonth(int month) { int mt = month; if (month == 1) return 12; return mt - 1; } // get what is the starting day of the month public static int getStartingDay(int month) { Calendar cal = Calendar.getInstance(); cal.set(Calendar.DAY_OF_MONTH, 1); // in calendar, month starts from 0 cal.set(Calendar.MONTH, month - 1); return cal.get(Calendar.DAY_OF_WEEK) - 1; } // get what is the maximum no of days in the month public static int getMaximumDays(int month) { Calendar cal = Calendar.getInstance(); // in calendar, month starts from 0 cal.set(Calendar.MONTH, month - 1); return cal.getActualMaximum(Calendar.DATE); } public static void main(String[] args) { Scanner keybd = new Scanner(System.in); String cmd = ""; int day = -1; int month = -1; loadEventsFromFile("calendarEvents.txt"); //load events at start up while (true) { System.out.println("Please type a command"); System.out.println("\t\"e\" to enter a date and display the corresponding calendar."); System.out.println("\t\"ev\" to enter an event."); System.out.println("\t\"fp\" to print calendar to file"); System.out.println("\t\"t\" to get todays date and display the todays calendar"); System.out.println("\t\"n\" to display the next month"); System.out.println("\t\"p\" to display the previous month"); System.out.println("\t\"q\" to quit the progrram"); cmd = keybd.nextLine(); if (cmd.equalsIgnoreCase("e")) { // get user input date System.out.print("Enter a date (m/d): "); String date = keybd.nextLine(); dayValue = day = dayFromDate(date); month = monthFromDate(date); showLine = true; drawCalendar(System.out, month, day); continue; } else if (cmd.equalsIgnoreCase("ev")) { // get user input date System.out.print("Enter an event (m/d event_title): "); String date = keybd.next(); String event = keybd.nextLine().trim(); int d = dayFromDate(date); int m = monthFromDate(date); eventArray[m-1][d-1] = event; } else if (cmd.equalsIgnoreCase("t")) { Calendar cal = Calendar.getInstance(); dayValue = day = cal.get(Calendar.DATE); month = cal.get(Calendar.MONTH) + 1; System.out.println(" Displaying calendar for today's date " + month + "/" + day); showLine = true; drawCalendar(System.out, month, day); } else if (cmd.equalsIgnoreCase("n")) { if (day != -1 && month != -1) { day = 1; dayValue = -1; // as user has not mentioned any value specifically month = nextGoodMonth(month); System.out.println(" Displaying calendar for next month " + month); showLine = true; drawCalendar(System.out, month, day); continue; } else { System.out.println("Please display a calendar first. "); continue; } } else if (cmd.equalsIgnoreCase("p")) { if (day != -1 && month != -1) { day = 1; // as user has not mentioned any value specifically dayValue = -1; month = previousGoodMonth(month); System.out.println(" Displaying calendar for previous month " + month); showLine = true; drawCalendar(System.out, month, day); continue; } else { System.out.println("Please display a calendar first. "); continue; } } else if (cmd.equalsIgnoreCase("fp")) { System.out.print(" Enter month to print (1-12):"); month = keybd.nextInt(); System.out.print("Enter filename: "); String fname = keybd.next().trim(); keybd.nextLine();//remove newline dayValue = -1; try { PrintStream outfile = new PrintStream(new File(fname)); drawCalendar(outfile, month, day); outfile.close(); } catch (FileNotFoundException e) { System.out.println(e.getMessage()); } } else if (cmd.equalsIgnoreCase("q")) { System.out.println("Thank you for using the calendar app."); System.out.println("Have a nice day."); break; } else { System.out.println("Please enter a valid command. "); continue; } } keybd.close(); } }
