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Thread: Help with reading from file

  1. #1
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    Post Help with reading from file

    I am currently making a program to read each char in a text file and adding it into an array.
    The problem is that it can't find the file. I have tried to print out the absolute path and the path is correct.

    I can't see what I'm going to change.

    Here's my code:

    package trust.src;
     
    import java.awt.List;
    import java.io.BufferedReader;
    import java.io.File;
    import java.io.FileReader;
     
    public class Level {
     
    	private int level;
    	private char[][] tiles;
    	private String[] lines;
     
    	public Level() {
    		tiles = new char[20][30];
    		level = 1;
    		getLevel();
    	}
     
    	public void getLevel() {
    		String fileName = "level" + Integer.toString(level) + ".txt";
     
    		try {
                            //creates the file.
    			File file = new File("res/levels/" + fileName);
    			String line;
    			int index = 0;
    			BufferedReader reader = new BufferedReader(new FileReader(file));
     
                            //reads the lines and add them into a String array.
    			while ((line = reader.readLine()) != null) {
    				lines[index] = line;
    				index++;
    			}
     
                            //reads each char in each line.
    			for (int i = 0; i < lines.length; i++) {
    				for (int j = 0; j < lines[i].length(); j++) {
    					tiles[i][j] = lines[i].charAt(j);
    					System.out.println(lines[i]);
    				}
    			}
    		}catch(Exception ex) {System.out.println("Error while loading level"); ex.printStackTrace();}
    	}
    }

    and this is the output i get:

    Error while loading level
    java.lang.NullPointerException
    	at trust.src.Level.getLevel(Level.java:30)
    	at trust.src.Level.<init>(Level.java:17)
    	at trust.src.Board.<init>(Board.java:8)
    	at trust.src.Trust.<init>(Trust.java:13)
    	at trust.src.Trust.main(Trust.java:18)

    I dont know what i should do.
    Please help me!


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Help with reading from file

    java.lang.NullPointerException
    at trust.src.Level.getLevel(Level.java:30)
    There is a variable on line 30 with a null value. Look at line 30, find the variable and then backtrack in the code to find out why the variable does not have a valid value.
    If you don't understand my answer, don't ignore it, ask a question.

  3. The Following User Says Thank You to Norm For This Useful Post:

    Dr.Code (July 2nd, 2012)

  4. #3
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    Default Re: Help with reading from file

    Omg, this is crazy. I backtracked the error and fixed it, but when I print out each line in the line array.
    I get, instead of 20 lines, 599 lines! I have no idea why.

    here is my text file(I know it looks wierd, but there are 20 rows, and 30 chars on each row):

    ##############################
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #_______________________OC___#
    ##############################
    ##############################

    And here is the 599 rows output I get:

    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
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    #____________________________#
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    #____________________________#
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    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
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    #____________________________#
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    #____________________________#
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    #____________________________#
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    #____________________________#
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    #____________________________#
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    #____________________________#
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    #____________________________#
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    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
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    #____________________________#
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    #____________________________#
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    #____________________________#
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    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
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    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #____________________________#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    #_______________________OC___#
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################
    ##############################

    This is really wierd, almost humoristic, but It's also REALLY annoying.
    I have no idea why this happens.

    Can somebody help me!

  5. #4
    Super Moderator Norm's Avatar
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    Default Re: Help with reading from file

    Post the new code with the problem.
    If you don't understand my answer, don't ignore it, ask a question.

  6. #5
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    Default Re: Help with reading from file

    Right, here's the code:

    package trust.src;
     
    import java.awt.List;
    import java.io.BufferedReader;
    import java.io.File;
    import java.io.FileReader;
     
    public class Level {
     
    	private int level;
    	private char[][] tiles;
    	private String[] lines;
     
    	public Level() {
    		lines = new String[20];
    		tiles = new char[20][30];
    		level = 1;
    		getLevel();
    	}
     
    	public void getLevel() {
    		String fileName = "level" + Integer.toString(level) + ".txt";
     
    		try {
    			File file = new File("res/levels/" + fileName);
    			System.out.println(file.getAbsolutePath());
    			String line;
    			int index = 0;
    			BufferedReader reader = new BufferedReader(new FileReader(file));
    			while ((line = reader.readLine()) != null) {
    				lines[index] = line;
    				index++;
    			}
     
    			for (int i = 0; i < lines.length; i++) {
    				for (int j = 0; j < lines[i].length(); j++) {
    					tiles[i][j] = lines[i].charAt(j);
    					System.out.println(lines[i]);
    				}
    			}
    		}catch(Exception ex) {System.out.println("Error while loading level"); ex.printStackTrace();}
    	}
    }

  7. #6
    Super Moderator Norm's Avatar
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    Default Re: Help with reading from file

    There is a nested loop where the println is located. How many times will the println() method be called inside those loops?
    Multiply it out to get the total number of times the println() method is called.
    Is that the number of lines that you want to print?
    If you don't understand my answer, don't ignore it, ask a question.

  8. The Following User Says Thank You to Norm For This Useful Post:

    Dr.Code (July 2nd, 2012)

  9. #7
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    Default Re: Help with reading from file

    LOL! I'm so stupid...
    Thx man!

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