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Index › Programming Questions & Help › Programs › StringIndexOutOfBoundsException
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StringIndexOutOfBoundsException (Read 1120 times)
Faradays_Cage
StringIndexOutOfBoundsException
May 19th, 2009, 1:46pm  
Hello,
I have a device that will take in ASCII over the serial port and display it on a 16*2 character LCD (Sparkfun SerLCD). I made a program that would pull the titles of articles from Slashdot using romefeeder and display them in a ticker like format on the lcd. However, when I try to run it, it displays the first headline and then gives me a "StringIndexOutOfBoundsException" error. I can't figure out why this happens. Can anyone help me?

Code:
Quote:
import processing.serial.*;
import net.obxlabs.romefeeder.*;
import com.sun.syndication.feed.synd.*;
Serial lcd;
Feeder feed;
SyndEntry entry;
int i = 0;
int n = 0;

void setup()
{
  frameRate(5);
  feed = new Feeder();
  lcd = new Serial(this, Serial.list()[1], 9600);
  feed.load("http://rss.slashdot.org/Slashdot/slashdot");
  feed.sort(Feeder.PUBLISHED_DATE);
  feed.setUpdateInterval(500);
  feed.verbose = true;
  feed.setProxy("http://www.brunonadeau.com/romefeeder/examples/SimpleFeed/applet/proxy.php");
  feed.startUpdate();
  entry = feed.next();
}

void draw()
{
  lcd.write(char(254)); //Stuff to put the "cursor" at the beginning of the LCD
  lcd.write(char(128));
  lcd.write("S l a s h d o t ");
  if (entry != null)
  {
    n = entry.getTitle().length();
  }
  if(i < n+16 && entry != null)
  {
    i++;
    lcd.write(entry.getTitle().substring(0+i, 16+i));
  } else {
    i = 0;
    entry = feed.next();
  }
}

/*
The output of this program looks like this:
 ______________
|S L A S H D O T |
|Tickerartcltitle    |

The titles scroll one character at a time.
**/
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NoahBuddy
Re: StringIndexOutOfBoundsException
Reply #1 - May 19th, 2009, 2:37pm  
Probably coming from
lcd.write(entry.getTitle().substring(0+i, 16+i));

Is (16+i) the highest possible or would it be (15+i)?

Highest index of an array is (length-1) since it starts at zero.
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Faradays_Cage
Re: StringIndexOutOfBoundsException
Reply #2 - May 19th, 2009, 3:16pm  
I tried changing the numbers around but I never got any results.
Thanks for the suggestion tho
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PhiLho 
Re: StringIndexOutOfBoundsException
Reply #3 - May 19th, 2009, 11:27pm  
Faradays_Cage wrote on May 19th, 2009, 1:46pm:
  if(i < n+16 && entry != null)
  {
    i++;
    lcd.write(entry.getTitle().substring(0+i, 16+i));
  } else {

I would increment i after the substring call, not before, unless you want to skip the first char.
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