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Deleting from arraylist and exporting back to .buab file(Java)

Answer 1

A:

Deleting stuff from a list is as easy as adding:

Contact contact = new Contact();
myListOfContacts.add(contact);    // adds a contact
myListOfContacts.remove(contact); // removes the contact

No more magic needed.

Edit

Please, and this is not Java, strictly separate three things, and your life will become much, much easier:

The model - your contacts stored in your arraylist(s)
The view - Your JFrame, showing the data from the model (the list(s))
The Controller - The code behind your buttons that does something with the model (adding, removing, changing data on the array list)

Maybe you've heard of the MVC pattern (model-view-controller).

So you don't 'export your' JList: on your View (the JFrame), you press a button and some code from your Controller (actually what you might have in your buttons action listener) is executed to write the model (your arraylist(s)) to the file.

Same goes for deleting, adding, importing. You 'do' something on the view (the GUI) to affect changes to the model (the list(s)).

As I said, this is not Java, this is a very, very common pattern for object oriented languages. Look at your code, try to find the model, the view, the controller and try to separate the code. Promise, once you've done it, the next assignements will be a joke.

Andreas_D 2009-11-30 23:40:46

and before closing the application don't forget the save ArrayLists in file

Nettogrof 2009-11-30 23:50:01

the contact information will be shown through the JTextFields, so the current contact information in the index will need to be deleted.Sorry im as thick as they come with java

Dave 2009-11-30 23:52:11

@Dave, you can delete from a ArrayList using the index, like txtNum.remove(index);

Nettogrof 2009-11-30 23:54:17

@nettogrof, error messages have come up, see below

Dave 2009-12-01 00:03:07

Answer 2

A:

@Nettogrof. Ive placed it in but its giving me errors.

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 2
 at java.awt.Container.remove(Unknown Source)
 at BasicGui.delete(BasicGui.java:340)
 at BasicGui.actionPerformed(BasicGui.java:149)
 at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
 at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
 at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
 at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
 at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
 at java.awt.Component.processMouseEvent(Unknown Source)
 at javax.swing.JComponent.processMouseEvent(Unknown Source)
 at java.awt.Component.processEvent(Unknown Source)
 at java.awt.Container.processEvent(Unknown Source)
 at java.awt.Component.dispatchEventImpl(Unknown Source)
 at java.awt.Container.dispatchEventImpl(Unknown Source)
 at java.awt.Component.dispatchEvent(Unknown Source)
 at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
 at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
 at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
 at java.awt.Container.dispatchEventImpl(Unknown Source)
 at java.awt.Window.dispatchEventImpl(Unknown Source)
 at java.awt.Component.dispatchEvent(Unknown Source)
 at java.awt.EventQueue.dispatchEvent(Unknown Source)
 at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
 at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
 at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 at java.awt.EventDispatchThread.run(Unknown Source)

Dave 2009-11-30 23:59:07

Dave, if possible, edit your original post to add more information

Andreas_D 2009-12-01 00:06:05

This kind of error ( java.lang.ArrayIndexOutOfBoundsException ) can happen when you try example to remove the 5th element, but your ArrayList have only 2 element. To be able to help with your specific code, we will need the important part ( not all) of your code

Nettogrof 2009-12-01 00:09:23

Its ok ive managed to delete from my array, now I need to be able to write the updated arraylist to the buab... help?

Dave 2009-12-01 00:11:51

Like your export functionality, just write the whole list and do not append but overwrite.

Andreas_D 2009-12-01 00:14:08

public void export(){ try { BufferedWriter fileOut = new BufferedWriter(new FileWriter( "contacts.buab", true)); fileOut.write(temp); fileOut.close(); } catch (IOException ioe) { JOptionPane.showMessageDialog(null, ioe.getMessage()); } txtName.setText(""); txtHomeNum.setText(""); txtMobNum.setText(""); txtHomeAdd.setText(""); }

Dave 2009-12-01 00:16:21

Answer 3

A:

public void export(){ try { BufferedWriter fileOut = new BufferedWriter(new FileWriter( "contacts.buab", true)); fileOut.write(temp);

  fileOut.close();
 } catch (IOException ioe) {
  JOptionPane.showMessageDialog(null, ioe.getMessage());
 }
 txtName.setText("");
 txtHomeNum.setText("");
 txtMobNum.setText("");
 txtHomeAdd.setText("");


}

Dave 2009-12-01 00:17:20

instead fileOut.wirte(temp) do a loop to write your arraylists data.

Nettogrof 2009-12-01 00:57:11

Answer 4

A:

Can anyone help?

Dave 2009-12-01 00:51:40

I know that your assignment is for the end of the month, but here it's not a chat room, and like Andreas_d told you, you can edit your post instead of adding "answer"

Nettogrof 2009-12-01 00:58:56

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Deleting from arraylist and exporting back to .buab file(Java)

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