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Hi everyone.
Currently trying to do a couple things with java and not having any luck.
I'm trying to grab the values of a couple text fields and write them to a text file (as one entry), then pull them to a j list, and be able to edit and remove single entries (comprising of multiple text fields)
Yeah, i'm guessing its a lot more work than I realise, and may be too much to help me with, if so, just tell me :beam:
pever.
If you do not need anything fancy then you can slurp the file during startup into the JList directly (notice that this approach blocks on I/O so it is not suitable for a program where the GUI must remain responsive at all times). The following example code will be something to build on: http://download.oracle.com/javase/tu.../ListDemo.java
Then add something like this:
If you need to simply convert multiple text fields -> JList and do edit/remove functions, why not simply concatenate strings and add them to the DefaultListModel, avoiding I/O overhead of unecessary writing to files... ?Code:import java.io.*;
/* more code */
private final DefaultListModel model;
/* slurp textFile into the list mode */
private void initList(String textFile, String encoding) {
try {
this.model=initList(new DefaultListModel(), textFile, encoding);
}
catch(Exception e) { e.printStackTrace(System.err); }
}
/* slurp text file into a list model: note that to use the default encoding of the host OS you should pass a null.*/
private DefaultListModel initList(DefaultListModel m, String textFile, String encoding) throws Exception {
BufferedReader br;
FileInputStream fis;
try {
// open file stream
fis = new FileInputStream(textFile);
// default to the standard encoding on the OS if not specified:
br = new BufferedReader(encoding == null? new InputStreamReader(fis) : new InputStreamReader(fis, encoding));
for(String s = br.readLine(), s!=null; s = br.readLine()) {
m.addElement(s);
}
return m;
}
finally {
if(fis!=null) { fis.close(); }
if(br!=null) { br.close(); }
}
}
Hey Tellos, thanks for the super quick reply.Quote:
Originally Posted by Tellos Athenaios
I'm very new to java, so that was still nothing to me. I'll work off what you've given me though, that should be enough.
Thank you very much.
:bow:
Well concatenating text from textfields is something like this:
Code:private String concat(JTextComponent ... components) {
StringBuilder sb = new StringBuilder();
for(JTextComponent c: components) {
sb.append(c.getText());
}
return sb.toString();
}
Sorry to be a pain, I've gone off on a tangent to the original idea, currently trying to get it removing elements from the list
Its throwing an error on listmodel, and again on adding items to the listCode:private void btnremoveActionPerformed(java.awt.event.ActionEvent evt) {
int index = listemail.getSelectedIndex();
listemail.remove(index);
int size = listModel.getSize();
if (size == 0) { //No email records left, disable the button
btnremove.setEnabled(false);
} else { //Select an index.
if (index == listModel.getSize()) {
//removed item in last position
index--;
}
listemail.setSelectedIndex(index);
listemail.ensureIndexIsVisible(index);
}
}
I grabbed the base code from http://download.oracle.com/javase/tu...t.html#mutable and modified it to fit the form I've got, but I can't figure out what I should be changing listModel to.Code:private void btnremoveActionPerformed(java.awt.event.ActionEvent evt) {
int index = listemail.getSelectedIndex();
listemail.remove(index);
int size = listModel.getSize();
if (size == 0) { //No email records left, disable the button
btnremove.setEnabled(false);
} else { //Select an index.
if (index == listModel.getSize()) {
//removed item in last position
index--;
}
listemail.setSelectedIndex(index);
listemail.ensureIndexIsVisible(index);
}
}
Man, why does java have to be so complicated. :laugh4:
Edit: Having moved on, I now can't run my darn program to test the other code I've written (thanks to your first post for the platform though :bow:)
It may work, but it can't find the main class, I think I scouted the problem, but it wants me to declare my public class in its own .java file (using netbeans 6.9)
I only added in that public class, because without it it my "class" does not have a main method.
:laugh4: I'm digging myself deeper into a hole.
You've copied the same code twice; but in the code sample that is supposed to remove things from the list you will notice (on careful reading) that at first you are using a variable called “listemail” (which I guess is a ListModel or DefaultListModel) and then you suddenly switch to “listModel” (different name) for what should logically remain the same list model (unless I'm missing something) and finally you switch back again to “listemail”. I expect that the code can be fixed by simply changing “listModel” to “listemail”.
Also for ease of reading I would advise you to clean up (i.e. make consistent) the source indentation. ~;)
Apologies for the indentation.
Yup, the variable 'listemail' is simply a jList, but changing 'listModel' to 'listemail' does not work.
Yet now that I've restarted my pc (other issues) and loaded it up, its not showing an error for listModel.
Oh well, ignoring that, the issue now is that I can't run the darn thing.
Attempting to run by any of the possible methods gives the error: "No main classes found".
So I add a public class above my 'main' (As I was getting an error related to that before) but it won't run without that having its own filename.java "class 'whatever name' is public, should be declared in a file named whatever name.java"
Creating a new file named the same doesnt help, I'm trying to call it or something, and nothing seems to be working. I'm kinda new, would you prefer if I started giving small screenshots of what exactly is happening?
Could you simply upload the entire source file as text, that way I can see how the various methods and variables ought to fit together.
Simply overwrite both form & java file with these contents:
Java: http://pastebin.com/dj4gHDu4
Form: http://pastebin.com/tTUygE7k
And then you may want to read carefully to see what I changed and where.
Thank you so very much Tellos, its still throwing an error though. it doesn't recognise this:
Code:import org.apache.commons.FileUtils;
Output from running is:Quote:
package org.apache.commons does not exist
Unused Import
I removed it as a test: it runs, it adds things to the email list, but doesnt remove and it doesnt write to file, but it doesnt throw an error. It does create the text file though.Code:run:
java.lang.ExceptionInInitializerError
Caused by: java.lang.RuntimeException: Uncompilable source code - package org.apache.commons does not exist
at my.contacteditor.ContactEditorUI.<clinit>(ContactEditorUI.java:16)
Could not find the main class: my.contacteditor.ContactEditorUI. Program will exit.
Exception in thread "main" Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)
Error of trying to remove:
Looking into it.Code:run:
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 7
at java.awt.Container.remove(Container.java:1136)
at my.contacteditor.ContactEditorUI.btnremoveActionPerformed(ContactEditorUI.java:342)
at my.contacteditor.ContactEditorUI.access$200(ContactEditorUI.java:22)
at my.contacteditor.ContactEditorUI$3.actionPerformed(ContactEditorUI.java:171)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.java:6263)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
at java.awt.Component.processEvent(Component.java:6028)
at java.awt.Container.processEvent(Container.java:2041)
at java.awt.Component.dispatchEventImpl(Component.java:4630)
at java.awt.Container.dispatchEventImpl(Container.java:2099)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4574)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
at java.awt.Container.dispatchEventImpl(Container.java:2085)
at java.awt.Window.dispatchEventImpl(Window.java:2478)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Well you used FileUtils.writeStringToFile() which is from Apache Commons. So you would need to have that library in an appropriate location or the classpath set appropriately to use it. The ArrayIndexOutOfBoundsException is due to an error on my part: (size -1) should've been size. The corrected version is at: http://pastebin.com/E7zL000f
As for FileUtils: you used it, so I assumed that you knew what you were doing and since it appears to be from Apache Commons I added a corresponding import statement. Clearly I was wrong. :tongue: Anyway, in Netbeans you can right click your project, go to “Properties” and add Libraries to your project there, that will ensure that the Classpath of your code is set appropriately for using the libraries. If you do not want to use FileUtils: you can remove:
And replace it with:Code:private void toFile () throws Exception {
// = null is needed to make the compiler happy otherwise it'll complain
// about unintialised variables.
FileWriter out = null;
try {
String name = txtname.getText();
String surname = txtsurname.getText();
String title = txttitle.getText();
String nickname = txtnickname.getText();
File outFile = new File("Customer.txt");
out = new FileWriter(outFile, true);
FileUtils.writeStringToFile(name, surname, nickname, title);
}
finally {
if (out != null) {
out.close();
}
}
}
Code:private void toFile () throws Exception {
// = null is needed to make the compiler happy otherwise it'll complain
// about unintialised variables.
java.io.PrintWriter out = null;
try {
String name = txtname.getText();
String surname = txtsurname.getText();
String title = txttitle.getText();
String nickname = txtnickname.getText();
File outFile = new File("Customer.txt");
out = new java.io.PrintWriter(new FileWriter(outFile, true));
// write contents to the file, one item per line
for(String line: new String[] { name, surname, nickname, title }) {
out.println(line);
}
out.flush();
}
finally {
if (out != null) {
out.close();
}
}
}
Yeah, you were kind of. :tongue:Quote:
Originally Posted by Tellos Athenaios
Everything works great, except it still isn't removing items from the list.
You've helped so much, if I knew you in real life, I'd owe you like 3 cases of beer. :laugh4:Code:run:
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 3
at java.awt.Container.remove(Container.java:1136)
at my.contacteditor.ContactEditorUI.btnremoveActionPerformed(ContactEditorUI.java:361)
at my.contacteditor.ContactEditorUI.access$200(ContactEditorUI.java:21)
at my.contacteditor.ContactEditorUI$3.actionPerformed(ContactEditorUI.java:170)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.java:6263)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
at java.awt.Component.processEvent(Component.java:6028)
at java.awt.Container.processEvent(Container.java:2041)
at java.awt.Component.dispatchEventImpl(Component.java:4630)
at java.awt.Container.dispatchEventImpl(Container.java:2099)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4574)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
at java.awt.Container.dispatchEventImpl(Container.java:2085)
at java.awt.Window.dispatchEventImpl(Window.java:2478)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Oh I see:should beCode:listemail.remove(index)
Code:listModel().remove(index)
:guitarist:Quote:
Originally Posted by Tellos Athenaios
How do I thank you Tellos. I can not thank you enough.