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GUImaster

Wed Jul 07, 2010 8:40 pm


Making a program for parents..need help.

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Im making a program for my parents...and i got stuck.  a part of what i need to do is 
**Using Netbeans 6.8**

*Needs Button*
*Needs TextField*
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Check To see if "input.txt" is empty

if "input.txt" is empty then
write "This is Header"
write "----------------"
write (Text in TextField)

if "input.txt" isnt empty then

append at end of file (Text in TextField)
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i had a basic idea of what i needed to do but it didnt work out for me 

Thanks in Advance



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Zren

Wed Jul 07, 2010 9:08 pm


Re: Making a program for parents..need help.

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Here's some code snippets to point you in a general direction of File Input/Output. Buttons are rather easy in netbeans so that shouldn't be the problem. If ya need more details just ask.

To find if the file exist (Copy n Paste, this forum doesn't like the brackets at the end. Or just look for exists yourself): http://download.oracle.com/docs/cd/E17476_01/javase/1.4.2/docs/api/java/io/File.html#exists()

File Size:
File f = new File("blarg.txt");
long file_size = f.length();

For writing to files: 
import java.io.*;
class FileWrite {
   public static void main(String args
Don't forget to close or flush the bufferedwriter or nothing will write to file.


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GUImaster

Wed Jul 07, 2010 9:49 pm


Re: Making a program for parents..need help.

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i have import.java.io.*;
and this code happens when the button is pressed

[code] try {
            fis = new FileInputStream("input.txt");
            
            in = new DataInputStream(fis);
            temp = in.readLine();
            in.close();
            
            fwriter5 = new FileWriter("input.txt", true);
            bfwriter2 = new BufferedWriter(fwriter5);
            if (temp.compareTo(" ")==0) {
                bfwriter2.write("Hello");
                bfwriter2.write("------------------");
                bfwriter2.write(jTextField1.getText());
                
            } else  {
                 
               // bfwriter2.write(jTextField1.getText());
            }
         
        } catch (IOException ex) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
        }
            [/code]

thats what i have after using netbeans gui bulder... but it doesnt work for me


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Zren

Wed Jul 07, 2010 10:04 pm


RE:Making a program for parents..need help.

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Did you clooooo~se the buffered writer?


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GUImaster

Wed Jul 07, 2010 10:06 pm


Re: Making a program for parents..need help.

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i dont exactly know where to close it....the try catch things always throw me off

[Update] I closed it in the if statement and i got the same error}

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException


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GUImaster

Wed Jul 07, 2010 10:20 pm


Re: Making a program for parents..need help.

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I got it working now...Thanks for the help

i changed the if (Temp.compareTo(" ")==0) to if (temp == null)