Jtextfield and array
Hi ALL
I'm trying to create a Jtextfield but i also want to have an array on the Textfield, is their a simple way of doing this. I have tried but failed so can anyone help please.
wen i try i get nopointerexception (frustrating)
yea i tried
int i;
for(i=0; i < array.length; i++)
JTextField[] array = new JTextField;
don't compile
Similar Messages
-
Array of JPanel and Array of JTextField?
Hi,
I try to create array of jpanel and inizialize it in "for" , but when run it give me this error message:
"Exception in thread "main" java.lang.NullPointerException"
at the row: "panInsCantante.add(panInsNCC);"
why?
(ps. i tried in another code to create array of jtextfield and it give me same error message..)
here part of code :
JPanel [] panInsCantante = new JPanel[3];
for(int i=0;i<=N;i++){
JPanel panInsNCC= new JPanel();
panInsNCC.setLayout( new GridLayout(3,1) );
panInsNCC.add(campoTesto1);
panInsNCC.add(campoTesto2);
panInsNCC.add(campoTesto3);
//panInsCantante[i] = new JPanel();
//panInsCantante.setLayout( new GridLayout(1,1) );
panInsCantante[i].add(panInsNCC);a question (theoric...)A VERY important question I may add.
what's the difference between ..
this instance :
JPanel [] panInsCantante = new
JPanel[3];This declares and initializes the array itself, nothing more. No JPanels have been initialized as yet, just the array. It's as if you have now built the shelves to hold the books, but you have no books up there yet...
and this instance of panInsCantante? :
panInsCantante[i] = new JPanel();and this initializes each JPanel in the array as you loop through the array. .... and now you have filled the shelves with the books and can use the books.
You will need them both.
In all likelihood, the reason for your confusion is that all of your previous arrays were arrays of primative types: int, double, float, and char. In this situation, you don't need to go through the step of initializing the variable.
But now you are faced for the first time with an array of reference type, an array of Objects. This is a different situation and requires the steps that we have gone through.
Message was edited by:
petes1234 -
JTextField [] and MouseEntered
Hello
I know this type of question has been asked in the forums before, but might is kind of different...i think.
I have an array of JTextFields and i want each of there color to turn to GRAY when the mouse is on top of them.
So if mouse is on top of TextField1 then only TextField1 turns GRAY.
my Current mouseEntered() method is this
public void mouseEntered(MouseEvent me)
for (int i=0; i < nasdaqTFs.length; i++){
nasdaqTFs.setEditable(false);
nasdaqTFs[i].setBackground(Color.GRAY);
This, obviously, turns ALL the TextFields to GRAY when the cursor is in the Panel. So cursor can be anywhere and they all turn GRAY.
So the question is...how do i find out when the Cursor is on the Specific TextField.Learning from earlier today This time i did write a Short Example of what i want done.
Maybe this time i didnt do a bad job at it
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Listener extends JFrame implements MouseListener
JTextField t;
JTextField t1;
public Listener ()
super ("test");
Container c = getContentPane();
c.setLayout(new BorderLayout());
t = new JTextField(4);
c.add(t, BorderLayout.NORTH);
t1 = new JTextField (4);
c.add(t1, BorderLayout.SOUTH);
addMouseListener(this);
setVisible(true);
setSize(300,300);
MouseMotionListener don = new MouseMotionAdapter(){
public void mouseEntered(MouseEvent me) {
System.out.println("Enterd)");
me.getComponent().setBackground(Color.GRAY);
t.addMouseMotionListener(don);
t1.addMouseMotionListener(don);
public static void main (String args[])
Listener l = new Listener ();
public void mouseEntered(MouseEvent me)
/*JTextField tf = (JTextField) me.getSource();
tf.setBackground(Color.GREEN);*/
me.getComponent().setBackground(Color.GREEN);
public void mouseExited(MouseEvent me)
/*JTextField tf = (JTextField) me.getSource();
tf.setBackground(Color.white);*/
me.getComponent().setBackground(Color.WHITE);
public void mousePressed(MouseEvent me){}
public void mouseReleased(MouseEvent me){}
public void mouseClicked(MouseEvent me){}
}This GUI wont change colors of TF's either. However when i move around the GUI i see somethin Green flickering! -
All the xml and arrays are getting NULL Problem
Hello guys
I am working on a project which uses xml loading, e4x and array manipulation extensively, and it was going good but now I got stuck on a strange problem. Whole code was fine and application was working and responding in a desired way, but then mystourisly it stopped working and started to retun NULL values to almost all the actionscript (internal) Arrays and XML varibales.
Now Whenever i load xml file and assign the loaded values to internal xml variables, internal values get only NULL instead of data.
Same is the situation with Arrays, I created some components in mxml, and when i passed them to arrays by reference, code gets compiled successfully, but again Array has only null values [that code was working fine too]
I am wondering if Adobe Flex did a silenced update or something similar and it is the result of that things !
I am using Adobe Flex 3.2 with SDK 3.3 on windows Vista Ultimate.
Please check this attached project, Import it and see if you face the same problem
Thanks
Link to Problem Project
http://isolatedperson.googlepages.com/problemXperiment.zip
Problem Screenshot
http://isolatedperson.googlepages.com/xmlissue.JPGUse HTTPService to load the data. You'll have fewer problems.
<?xml version="1.0" encoding="utf-8"?>
<mx:Application creationComplete="dataSvc.send();"
xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
<mx:Script>
<![CDATA[
import mx.collections.XMLListCollection;
import mx.rpc.events.ResultEvent;
[Bindable] private var xlc:XMLListCollection;
private function loadXML(evt:ResultEvent):void{
xlc = new XMLListCollection(evt.result.individual.@id as XMLList);
]]>
</mx:Script>
<mx:HTTPService resultFormat="e4x" result="loadXML(event)" url="alirazaTree.xml" id="dataSvc"/>
<mx:ComboBox id="cbx" dataProvider="{xlc}"/>
</mx:Application> -
Hi,
I'm a freshman in college and new to java. I am completely lost and really need help with a current assignment. Here are the instructions given by my teacher...
Building on provided code:
Loops and Arrays
Tracking Sales
Files Main.java and Sales.java contain a Java application that prompts for and reads in the sales for each of 5 salespeople in a company. Files Main.java and Sales.java can be found here http://www.ecst.csuchico.edu/~amk/foo/csci111/labs/lab6N/Main.java
and here http://www.ecst.csuchico.edu/~amk/foo/csci111/labs/lab6N/Sales.java It then prints out the id and amount of sales for each salesperson and the total sales. Study the code, then compile and run the program to see how it works. Now modify the program as follows:
1. (1 pts) Compute and print the average sale. (You can compute this directly from the total; no new loop is necessary.)
2. (2 pts) Find and print the maximum sale. Print both the id of the salesperson with the max sale and the amount of the sale, e.g., "Salesperson 3 had the highest sale with $4500." Note that you don't necessarily need another loop for this; you can get it in the same loop where the values are read and the sum is computed.
3. (2 pts) Do the same for the minimum sale.
4. (6 pts) After the list, sum, average, max and min have been printed, ask the user to enter a value. Then print the id of each salesperson who exceeded that amount, and the amount of their sales. Also print the total number of salespeople whose sales exceeded the value entered.
5. (2 pts) The salespeople are objecting to having an id of 0-no one wants that designation. Modify your program so that the ids run from 1-5 instead of 0-4. Do not modify the array-just make the information for salesperson 1 reside in array location 0, and so on.
6. (8 pts) Instead of always reading in 5 sales amounts, allow the user to provide the number of sales people and then create an array that is just the right size. The program can then proceed as before. You should do this two ways:
1. at the beginning ask the user (via a prompt) for the number of sales people and then create the new array
2. you should also allow the user to input this as a program argument (which indicates a new Constructor and hence changes to both Main and Sales). You may want to see some notes.
7. (4 pts) Create javadocs and an object model for the lab
You should organize your code so that it is easily readable and provides appropriate methods for appropriate tasks. Generally, variables should have local (method) scope if not needed by multiple methods. If many methods need a variable, it should be an Instance Variable so you do not have to pass it around to methods.
You must create the working application and a web page to provide the applications information (i.e., a page with links to the source code, the javadoc and an object model) to get full credit. You can use the example.html's from the last two labs to help you remember how to do this.
I'm not asking for someone to do this assignment for me...I'm just hoping there is someone out there patient and kind enough to maybe give me a step by step of what to do or how to get started, because I am completely lost from the beginning of #1 in the instructions.
Any help would be much appreciated! Thank you!
Message was edited by:
Scott_010
Message was edited by:
Scott_010First ask the person who gave this asignment as to why do you require two classes for this , you can have only the Sales.java class with main method in it . Anyways.
Let Main.java have a main method which instanciates a public class Sales and calls a method named say readVal() in Sales class.
In the readVal method of sales class define two arrays i.e ids and sales. Start prompting the user for inputting the id and sales and with user inputting values keep storing it in the respective arrays .. Limit this reading to just 5 i.e only 5 salesPerson.
Once both the arrays are populated, call another method of Sales class which will be used for all computations and output passing both the arrays.
In this new method say Compute() , read values from array and keep calculating total,average and whatever you want by adding steps in just this loop. You can do this in readval method too after reading the values but lets keep the calculation part seperate from input.
You must create the working application and a web page to provide the applications information (i.e., a page with links to the source code, the javadoc and an object model) to get full credit. You can use the example.html's from the last two labs to help you remember how to do this. I think this is ur personal stuff , but if you want to use web page , you probably will require to use servlet to read values from the html form passed to the server. -
Reading values from JTextField and using them?
Hello,
I am trying to make a login screen to connect to an oracle database. Im pretty new to creaing GUI. I need help with reading the values from the JTextField and to be able to use them for my connection. So do I need to apply a listener? How do I go about doing that in this project. Thanks for any code or advice.
import java.util.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;
import java.sql.*;
public class UserDialog
String databaseURL;
String driver;
String database;
String username;
String password;
String hostname;
String port;
UserDialog() {
getInfo();
static String[] ConnectOptionNames = { "Login", "Cancel" };
static String ConnectTitle = "Login screen";
public void getInfo() {
JPanel connectionPanel;
JLabel databaseURLLabel = new JLabel("Database URL: ", JLabel.LEFT);
JTextField databaseURLField = new JTextField("");
JLabel driverLabel = new JLabel("Driver: ", JLabel.LEFT);
JTextField driverField = new JTextField("");
JLabel databaseLabel = new JLabel("Database: ", JLabel.LEFT);
JTextField databaseField = new JTextField("");
JLabel usernameLabel = new JLabel("User Name: ", JLabel.LEFT);
JTextField usernameField = new JTextField("");
JLabel passwordLabel = new JLabel("Password: ", JLabel.LEFT);
JTextField passwordField = new JPasswordField("");
JLabel hostnameLabel = new JLabel("Host Name: ", JLabel.LEFT);
JTextField hostnameField = new JTextField("");
JLabel portLabel = new JLabel("Port: ", JLabel.LEFT);
JTextField portField = new JTextField("");
connectionPanel = new JPanel(false);
connectionPanel.setLayout(new BoxLayout(connectionPanel,
BoxLayout.X_AXIS));
JPanel namePanel = new JPanel(false);
namePanel.setLayout(new GridLayout(0, 1));
namePanel.add(databaseURLLabel);
namePanel.add(driverLabel);
namePanel.add(databaseLabel);
namePanel.add(usernameLabel);
namePanel.add(passwordLabel);
namePanel.add(hostnameLabel);
namePanel.add(portLabel);
JPanel fieldPanel = new JPanel(false);
fieldPanel.setLayout(new GridLayout(0, 1));
fieldPanel.add(databaseURLField);
fieldPanel.add(driverField);
fieldPanel.add(databaseField);
fieldPanel.add(usernameField);
fieldPanel.add(passwordField);
fieldPanel.add(hostnameField);
fieldPanel.add(portField);
connectionPanel.add(namePanel);
connectionPanel.add(fieldPanel);
// Connect or quit
databaseURL = databaseURLField.getText();
driver = driverField.getText();
database = databaseField.getText();
username = usernameField.getText();
password = passwordField.getText();
hostname = hostnameField.getText();
port = portField.getText();
int n = JOptionPane.showOptionDialog(null, connectionPanel,
ConnectTitle,
JOptionPane.OK_CANCEL_OPTION,
JOptionPane.PLAIN_MESSAGE,
null, ConnectOptionNames,
ConnectOptionNames[0]);
if (n == 0) {
System.out.println("Attempting login: " + username);
String url = databaseURL+hostname+":"+port+":"+database;
// load the JDBC driver for Oracle
try{
DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
Connection con = DriverManager.getConnection (url, username, password);
System.out.println("Congratulations! You are connected successfully.");
con.close();
System.out.println("Connection is closed successfully.");
catch(SQLException e){
System.out.println("Error: "+e);
else if (n == 1)
System.exit(0);
public static void main (String args []) {
UserDialog ud = new UserDialog();
}thanks again,
Jamesthe reason why you can't get the text is because you are reading the value before some actually inserts anything in any fields.
Here is what you need to do:
Create a JDialog/JFrame. Create a JPanel and set that panel as contentPane (dialog.setContentPane(panel)). Insert all the components, ie JLabels and JTextFields. Add two buttons, Login and Cancel to the panel as well. Now get the username and password field values using getText() inside the ActionListener of the Login.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class LoginDialog extends JDialog
String username, password;
public LoginDialog( ){
setTitle( "Login" );
JPanel content = new JPanel(new GridLayout(0, 2) ); // as many rows, but only 2 columns.
content.add( new JLabel( "User Name" ) );
final JTextField nameField = new JTextField( "" );
content.add( nameField );
content.add( new JLabel( "Password" ) );
final JTextField passField = new JTextField( "" );
content.add( passField );
JButton login = new JButton( "Login" );
login.addActionListener( new ActionListener(){
public void actionPerformed( ActionEvent ae ){
username = nameField.getText();
password = passField.getText();
// call a method or write the code to verify the username and login here...
content.add( login );
JButton cancel = new JButton( "Cancel" );
cancel.addActionListener( new ActionListener( ){
public void actionPerformed( ActionEvent ae ){
dispose(); // close the window or write any code that you want here.
content.add( cancel );
pack( ); // pack everything in the dialog for display.
show(); // show the dialog. -
Hi all
My problem is that i have a JTextfield that is connected to a Oracle database that allow the user to enter data in the database. I want to have a button that will allow the user to test to see whether the data entered in the textfield is valid.
I'm not sure if i need to use sqlj or not. Any help would be gladly received.
Thanks
nullHmmm... lots and lots of ways to handle this, depending on your particular need for the particular type of 'validation'. ( More info? )
"JTextField" is not connected to a database in the same way that the infoswing "TextFieldControl" is.. .therefore one could trap the event ActionPerformed off the JTextField and do the checks ( or use the jbutton like you suggest..but it would seem like you'd always want it checked and corrected before continuing towards the inevitable commit attempt??? ).
You can use sqlj, or you can not use it... depends upon the way you've architected your application/environment and your needs and desires.
Note (if you haven't already ) that you can also do a heck of a lot of validation at the entity/view object level.
In my case ( an application ) I have a jdbc connection up at the front end for all my miscellaneous stuff, and a validate PL/SQL stored function. The nice things about using stored procedures/functions are that the validate routines can be nested for quick and easy use by triggers and stored procedures. If you put it outside the database it gets more fun should you want to get at the common validation routines from all approaches.
Curious as to how other folk are architecting their validations.... -
JTextField and JButtons not appearing until clicked.
I'm writing a program to refresh my CS1 java skills. For some reason when I try to add a JTextField and two JButtons to my container they don't appear until Ive clicked them.
Actually more specifically, this only happens after a 100ms wait after setting the frame visible. Any less and the components wind up visible, but scrunched up in the top middle of my frame.
Ive found that if I add the components before and after the wait they are visible and in the correct place, but this makes a noticeable flicker.
I'm running windows vista if that matters.
If someone could help me I would appreciate it.
snippet of code:
public scrollText()
drawingThread.start();
mainFrame.setSize(640,160);
mainFrame.setContentPane(draw);
mainPane = mainFrame.getContentPane();
mainPane.setBackground(Color.white);
mainFrame.setResizable(false);
mainFrame.setVisible(true);
try
Thread.sleep(100);
addInterface();
catch(InterruptedException e){}
public void addInterface()
textInput.setBounds(1,103,501,31);
play.setBounds(502,103,65,30);
play.addActionListener(this);
stop.setBounds(568,103,65,30);
stop.addActionListener(this);
mainPane.add(textInput);
mainPane.add(play);
mainPane.add(stop);
}Postings can't be moved between forums. Now you know for the next time.
The general form for building a GUI is
frame.getContentPane().add( yourComponentsHere );
frame.pack();
frame.setVisible( true );Then all the compnoent will show up according to the rules of the layout managers used.
However is you add components to the GUI "after" the GUI is visible then the components are not automatically painted. You need to tell the GUI to invoke the layout manager again so your code would be:
frame.getContentPane().add( componentsToVisibleGUI );
frame.getContentPane().validate(); -
Hi everyone (and sorry for my english language....).
I've this problem:
I've a Frame with a JtextField and a button. When I click on this button, I want to show a list of data from a database and then I must choose a value that must go to the JtextField.
Have you an idea how I can implement this? Sorry for this generic question, but I don't know how to do..
Thank you!>
As to your question.
I've a Frame with a JtextField and a button. When I click on this button, I want to show a list of data from a database and then I must choose a value that must go to the JtextField.
Have you an idea how I can implement this? ..Sure, plenty of people. But they will want to know exactly what you are having trouble with. E.G.
- Getting data from a DB.
- Putting data into a JList.
- Adding listeners to that JList so that choices are acted on, rather than simply high-lighted as the selection.
- Using the event provided to the listener, to update the JTextField.
- Adding a JTextField and JList to a JFrame using layout managers.
If your answer is 'all of that', then I suspect they would be tempted to:
a) Advise you to put this project aside until you have considerably more experience.
b) Refer you to the [Java Tutorial|http://java.sun.com/docs/books/tutorial/]. -
JTextField and JTextArea don't get focus occuasionally
I am developing a Java Swing Applet. At edit mode, JComboBox, JCheckBox, JRadioBox, and JButton work fine, but JTextField and JTextArea can't get focus occuasionally while I click them.
Anyone has idea?
ThanksThank you Himanshu,
but that's not exactly what my issue is. This link describes the undesired effect of ending up outisde of the player window and in the browser.
My problem is kind of the opposite. When I launch the page in the html file I cannot use the tab key to get to any of the controls in the captivate window. I'm stuck in the browser unless I click on the captivate window. That is not acceptable if we want it accessible without using a mouse. I found a way to make it work for chrome like I stated above, but not in FF. Do you have any ideas for this?
Thanks!
Monique -
Hi!
How do I limit the character number that can be inserted into a JtextField and JPasswordField.
For examen is the Password can be mam 6 characters, how do I do from limit the input?
ThanksThe most common way to limit what is entered in a JTextField is to create your own document. See the following thread:
http://forum.java.sun.com/thread.jsp?forum=57&thread=414464
Graeme -
I am using an JTextField and I want to be notified when the text there have been changed. But there is no TextListener accessible in JTextField. Do I have to modify a CaretListener ?
many Thanks/ SamI am using an JTextField and I want to be notified
when the text there have been changed. But there is no
TextListener accessible in JTextField. Do I have to
modify a CaretListener ?DocumentListener. -
I have a JTextField and I am trying to set it up so it is somewhat transparent.
mTextField.setBackground(new Color(255,255,255,50));
But what happens when i do that is this: the textfield as a text value gets the text that i have set up for one of the neighbouring components.
I am not sure why this happens.
Has anyone experienced this problem before? Is there a fix to it?
I tried setting up the text using setText to an empty string but it happens agian. I dont have this problem when the transparency is Not set.
Cheers
DanI am not sure why this happens. An opaque component is responsible for painting the entire area of the component, which basically means that the RepaintManager doesnt' have to worry about the garbage that may exist where the component is about to be repainted.
Since you background is somewhat transparent, you can see the garbage left behind. (Don't ask me what its left behind from, thats in the details of the Swing repaint manager which I know nothing about).
Michaels suggestion makes the component transparent which means Swing will paint the background of the components parent. However when you do this, the background of your component isn't painted.
So heres a solution that paints the background of the parent and the child:
JTextField textField = new JTextField("Some Text")
protected void paintComponent(Graphics g)
g.setColor( getBackground() );
g.fillRect(0, 0, getSize().width, getSize().height);
super.paintComponent( g );
textField.setBackground(new Color(0, 255, 255, 50));
textField.setOpaque( false ); -
Accelerators, JTextField, and focus
I created a JMenuItem for Save. I also created an accelerator for the Save menu item.
JMenuItem saveItem;
JMenu fileMenu = new JMenu ("File");
fileMenu.add (saveItem = new JMenuItem ("Save"));
saveItem.setMnemonic ('S');
KeyStroke cntrlS = KeyStroke.getKeyStroke(KeyEvent.VK_S,
Event.CTRL_MASK);
saveItem.setAccelerator (cntrlS);
saveItem.addActionListener (new ActionListener() {
public void actionPerformed (ActionEvent e) {
doSaveNote();
When the user is finished entering data into the JTextField(s), the user then either presses ctrl-S or clicks on the Save button on the menu. My code (not shown) validates data in JTextFields when the Save accelerator or button is pressed (blank field is considered invalid as well as wrong flight number). If data is invalid, then the first field with invalid data gets focus.
If the JTextField has focus and invalid data is there, then when the user clicks the Save button the JTextField still has focus with a message letting the user know the data is invalid. However, if the user puts invalid data in the JTextField and uses the accelerator ctrl-S without tabbing out of the field first, the invalid JTextField does not get focus and no error message is presented. When using the accelerator the invalid JTextField only gets focus and prints an error message if the user tabs out of the JTextField befor pressing ctrl-S.
I don't want to tab out of the field. Why is the behavior different between the accelerator and clicking the Save button? Any help is appreciated.You can request focus for another component.
Or you could do: myTextField.setFocusable(false). But in this case you would have to make it fosucable later on if you want to use it. -
Challeging Traversal of Vector and Array
Hi there ! I would like to render the values of this Vector and Array . How do I print it out to the browser ?
try
ResultSet rset = stmt.executeQuery(myQuery);
System.out.println(" Finish Execute Query !!! ");
/* Array Contruction */
int numColumns = rset.getMetaData().getColumnCount();
while (rset.next())
aRow = new String[numColumns];
for (int i=0; i < numColumns; i++){
aRow[i] = rset.getString(i+1);
allRows.addElement(aRow);
return allRows;
}Hi there !
Thanks for your help but I managed to get it working. For references purposes, I`ll post it here.
My problem now is this :-
How can I issue another SQL statement and store the results in the same array?
Pls note . One Sql per table so, that`s the issue ?
Can someone help with a followup code ?
try
ResultSet rset = stmt.executeQuery(myQuery);
System.out.println(" Finish Execute Query !!! ");
/* Array Contruction */
int numColumns = rset.getMetaData().getColumnCount();
while(rset.next())
// for every record instance aRow
aRow = new String[numColumns];
// store in aRow the values of the record
for(int i=0;i<numColumns;i++)
aRow[i] = rset.getString(i+1);
//When aRow is full store it in the vector
allRows.addElement(aRow);
// when the rset finished print all the Vector
for(int i=0;i<allRows.size();i++)
// get returns a String[]
String[] tmpRow = (String[])allRows.get(i);
for(int j=0;j<tmpRow.length;j++)
out.print(tmpRow[j]+" ");
out.println("");
}
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