I am learning Java with Swing and I have some problems with using JTextField. In my program I want to dynamically add a few JTextFields with some text:
while( (ln = bufFile.readLine()) != null ) {
// inIdPanel is JPanel
inIdPanel.add(new JTextField(ln));
}
And it works good. However, the content of these JTextFields can be modified by users, and later I want to call getText() from all of them. Is this possible? How can I do this?
I saw this question: Java Swing: JButton creates new JTextField(s) but this isn't enough to solve my problem (I think using arrays in my case is not a good idea but maybe I'm wrong).
The reason why you cannot call getText() is that you have not stored a reference to the JTextField when you created it. You will need to use an array or collection to store the JtextFields as you create them so you can call the method on them later. A collection will be easier than an array because you do not know how many lines you will read in so you want it to be able to grow.
List<JTextField> fields = new ArrayList<JTTextField>();
while( (ln = bufFile.readLine()) != null ) {
JTextField field = new JTextField(ln);
inIdPanel.add(field);
fields.add(field);
}
Then you can call the .getText() from all of them
for(JTextField field: fields){
System.out.println(field.getText());
}
For an easy solution, just add an ArrayList<JTextField> textFieldList and add to the code you posted:
while((ln = bufFile.readLine()) != null) {
textFieldList.add(new JTextField(ln));
inIdPanel.add(textFieldList.get(textFieldList.size()-1));
}
Then, when you want to access the text fields, you simply iterate through them, e.g.
for (JTextField jtf : textFieldList) {
/* Operate on jtf, call methods, etc */
}
You could replace the ArrayList with an array if there is a defined limit on how many text fields you could add, but the list is nice if that quantity is unknown.
Related
I've created an ArrayList with my EditText inputs for Android. This is in main activity
First i check if any are empty
for(EditText i: inputs){
if(i.getText().toString() == null){
empty = true;
}
then
if (!empty){
for(EditText i: inputs) {
String input = i.getText().toString();
Person gen = new Person(inputFirstName.getText().toString(),
inputLastName.getText().toString(), inputMaiden.getText().toString(),
inputBirth.getText().toString(), inputBrand.getText().toString());
}else{ createAlertDialog("Alert", "One or more inputs are empty"); }
I'm aware in its current state it won't work, and just create 5 instances of the Person object. That is the layout of the constructor, and I want to find out the cleanest way to construct the object.
The repetition of .getText().toString() is dirty. Surely there is a cleaner way to do this using the ArrayList properties
It may appear to be an advanced approach but you may find Android DataBinding useful.
http://developer.android.com/tools/data-binding/guide.html
I'm not sure how to ask this question, and I'm certain that there's some kind of other solution to the problem I'm having so if anyone can point me in the right direction, I'd appreciate it.
In any case, the issue I'm having is that I have a String[] list (called "projects") that I'm using to populate a combo box. I want to use the selection from the combo box to dynamically change the form fields listed in a GUI panel.
My approach, so far, isn't dynamic enough because I will have nearly 100 possible selections from the combo box when I'm done. So far, I've been testing with 3 options in the box, but scaling it up to 100 will involve a lot of code, and I think there MUST be some other solution, right? I just don't know what that solution is.
String[] projects = {"Select a project...", "Option1", "Option2", "Option3"};
String[] Option1= {"phone", "maxphv"};
String[] Option2= {"address1", "address2", "house", "predir", "street", "strtype", "postdir", "apttype", "aptnbr"
, "city", "state", "zip"};
String[] Option3= {"phone"};
ArrayList<String> fieldslist, fieldslbllist;
Ideally, I'd like to take the name of the project selected from the projects String[] combo box and reference that name as the name of another list that contains the fields I want to display in the panel.
But I gather from reading on other questions that the name of a variable is irrelevant once the code is compiled.
At this point, I have a set of code to clear the panel and dynamically select the fields, but I still have to manually code the replacement for each of the 100 options. That's not terrible, I suppose, but I think that there is probably a better way that I am unaware of.
public void resetFields() {
fieldslist.clear();
fieldslbllist.clear();
}
public void setFields() {
if (project.getSelectedIndex() == 0) {
resetFields();
}
else if (project.getSelectedIndex() == 1) {
resetFields();
for (int i = 0; i <= Option1.length; i++) {
fieldslist.add(Option1[i]);
fieldslbllist.add(Option1[i]+"lbl");
}
}
else if (project.getSelectedIndex() == 2) {
resetFields();
for (int i = 0; i <= Option2.length; i++) {
fieldslist.add(Option2[i]);
fieldslbllist.add(Option2[i]+"lbl");
}
}
//... onward to 100
The above is just a loop that resets the display on selection of a new option in the combo box and then loops through the options in the OptionX String[] list and adds the values to the fields Array.
Is this a viable way to handle dynamic UI coding? And, is there any way to set it up so I will only have to specify which fields belong to each value and then not have to code a section for each possible project.getSelectedIndex() value in setFields()?
Use CardLayout, seen here, to change the form dynamically. Given the large number of alternatives, look for a hierarchical breakdown among the choices that might allow you to use two related controls, as shown here.
I'm trying to create a Java GUI dynamically by taking values from a result set and using it to generate a checklist. I've created a small demo program to demonstrate what I've done:
SQL Commands
CREATE USER 'test'#'localhost' IDENTIFIED BY 'testpw';
CREATE DATABASE combotest;
USE combotest;
CREATE TABLE combotable (
id INT(5) NOT NULL PRIMARY KEY auto_increment,
type VARCHAR(50) NOT NULL);
INSERT INTO combotable (id, type) VALUES
(default, 'Label'),
(default, 'Textfield'),
(default, 'Combo'),
(default, 'Label'),
(default, 'Textfield'),
(default, 'Combo'),
(default, 'Combo');
GRANT SELECT ON combotest.* TO 'test'#'localhost';
For your convenience if you'd like to test it yourself I've put all the SQL commands above.
Now, for my Java code:
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;
import javax.swing.*;
public class resToComboDemo implements ActionListener {
//JDBC Variables
static Connection connect = null;
static Statement statement = null;
static ResultSet res = null;
#SuppressWarnings("rawtypes")
//Other Variables
JComboBox comboBox;
JButton submit;
JFrame frame;
JLabel label;
JTextField textField;
Container pane;
public static void main(String[] args) throws SQLException {
new resToComboDemo();
}
public resToComboDemo() throws SQLException {
try {
Class.forName("com.mysql.jdbc.Driver");
// Setup the connection with the DB
connect = DriverManager
.getConnection("jdbc:mysql://localhost/combotest?"
+ "user=test&password=testpw");
statement = connect.createStatement();
//Note: in this specific case I do realize that "order by id" is not necessary. I want it there, though.
res = statement.executeQuery("SELECT * FROM combotable ORDER BY id");
createStuff(res);
} catch (Exception e) {
JOptionPane.showMessageDialog(null, "Error 1: "+e, "Error!", JOptionPane.ERROR_MESSAGE);
} finally {
connect.close();
}
}
#SuppressWarnings({"rawtypes", "unchecked" })
public void createStuff (ResultSet res) throws SQLException {
frame = new JFrame("Testing dynamic gui");
Dimension sD = Toolkit.getDefaultToolkit().getScreenSize();
int width = sD.width;
int height = sD.height - 45;
frame.setSize(width,height);
pane = frame.getContentPane();
pane.setLayout(new GridLayout(0, 2));
while (res.next()) {
Object[] options = { "Pass", "Fail"};
String type = res.getString("type");
JLabel label = new JLabel("<html><small>"+type+"</small></html>");
JLabel blank = new JLabel(" ");
blank.setBackground(Color.black);
blank.setOpaque(true);
if (type.equals("Label")) {
label.setBackground(Color.black);
label.setForeground(Color.white);
label.setOpaque(true);
pane.add(label);
pane.add(blank);
} else if (type.equals("Combo")) {
pane.add(label);
comboBox = new JComboBox(options);
pane.add(comboBox);
} else if (type.equals("Textfield")) {
pane.add(label);
textField = new JTextField(20);
pane.add(textField);
}
}
JLabel blank2 = new JLabel(" ");
pane.add(blank2);
submit = new JButton("Submit");
submit.addActionListener(this);
pane.add(submit);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
#Override
public void actionPerformed(ActionEvent e) {
}
}
Now, everything works great with creating the GUI here. However, I need to be able to treat the Combobox and Textfield components as their own separate entities. Meaning, I want to be able to get user input from each different component. Right now, if I were to request information from textfield, it just gives me the information from the last textfield. This makes perfect since, because that's how java reads it. I have no problem with that.
I just can't for the life of me figure out how to get each component's input separately. Perhaps by taking the result set and adding the results to some type of array? I've attempted this multiple times in different flavors and I can't get it to come out the way I need it to. Some of you are going to request that I show you what I've tried... but honestly, it's not worth it.
And, before anybody asks: No, I will not use FlowLayout. :)
Any help is greatly appreciated!
There are probably a few ways to achieve this based on what you want to do...
If you are only performing a batch update, you could use a Map keyed to the id of the row and mapping to the Component.
This way, when you want to save the values back to the database, you would simply iterate the Maps key values, extract the Component associated with each key and then extract the value of the Component...
I might consider making a wrapper interface which has a simple getText method and wrap the component within it, making the implementation of the wrapper responsible for extracting the text, but that's just me ;)
If you want to perform updates when a individual component is updated, you would need to swap the mapping, so that the Component would the key and the id would be mapped to it.
This would mean that when some kind of event occurred that would trigger and update (ie a ActionEvent), you could extract the source from the event and look up the id in the Map based on the Component that caused the event...
Now...frankly, I would simply use a JTable and create a custom TableModel which could model all this.
This would require you to create POJO of the table, maintaining the id, type and value within a single object. This would define a basic row in the table.
The only problem is you would need to create a (reasonably) complex TableCellEditor that could take the type and return an appropriate editor for the table. Not impossible, it's just an additional complexity beyond the normal usage of a table.
This would all the information you need is available in a single object of a single row in the table.
Take a look at How to use tables for more details
Equally, you could use a similarly idea with the Map ideas above...
You could also simply create a self contained "editor" (extending from something like JPanel), which maintain information about the id and type and from which you could extract the value and simply keep a list of these....for example...
what about interrogating the Container ( pane) which contains the components
getComponents() method and loop through the sub component and check for JComobox and JTextField do the required cast and retrieve the value
Just an idea in case you are against adding the sub-components into a kind of list
You only have a reference to the last text field or combo box that you create, since you are reusing the variables that hold them. I would put them in an ArrayList, store each new text field and combbox as you create them, then you can go back and get input from all of them after you're done.
---------- (after the OP's response to the above paragraph)
No, there is no "place to refer you" -- it's your set of requirements, it would be pretty remarkable to find code that already existed that did this exact thing. Java and Swing give you the tools, you need to put things together yourself.
You don't show your "actionPerformed" routine, but let's hypothesize about it for a minute. It is called by the framework when an action is done, and it is passed an "ActionEvent" object. Looking through its methods, we find that it has "getSource()", so it will give you a reference to the component which generated the event.
Let's further think about what we have -- a set of components in the UI, and ones which can generate events are interesting to us. We want to, in this case, retrieve something from the component that generated the event.
If we have the component (from actionEvent.getSource()) and we want to do something with it, then we can, at worst do something like the following in the actionPerformed() method:
Component sourceComponent = actionEvent.getSource();
if (sourceComponent instanceof JComboBox)
{ JComboBox sourceBox = (JComboBox) sourceComponent;
// get the value from the combo box here
}
else if (sourceComponent instanceof JTextField)
{ JTextField sourceTextField = (JTextField) sourceComponent;
// get the value from the text field here
}
// or else do nothing -- our action was not one of these.
Done this way, you don't even need to keep a list of the components -- the UI is keeping a reference to all of them, and you just use that reference when the actionEvent occurs.
Now, this is not the only or even the best or the simplest way of doing this. If you wanted to extend JComboBox and JTextField with your own classes, you could have those classes both implement an interface that defined something like getValue() or getText; then you would not need the ugly instance of operator, which can usually be done away with by better design and planning.
I've put together a few methods that are suppose to delete a searched item from an array and the data from the array is also being put into a JTable through a method called createLoginTable().
When my delete button actionListener Method is carried out the element or login is successfully deleted from the array: 'listOfLogins' but the element does not appear to be deleted from the JTable as it is still there.
Here are the methods starting with the actionListener:
if(e.getSource()==deleteLoginButton)
{
int loopNo = list.nextLogin; ///Variables used in the 'removeLogin' Method
String foundLogin = list.listOfLogins[foundLocation].toString();
Login[] loginList = list.listOfLogins;
LoginList list = new LoginList(); //The 'list' is wiped
list.removeLogin(loginList, foundLogin, loopNo);
list.writeLoginsToFile(); //Writes logins to file (not integral to the array)
String[][] loginTableLogins = new String[50][2]; //Wipes the JTable Array
createLoginsTable(); //Creates the JTable
searchLoginButton.setEnabled(true);
editLoginButton.setEnabled(false);
deleteLoginButton.setEnabled(false);
addLoginButton.setEnabled(true);
}
This is the 'removeLogin' Method (This is in a seperate 'list' class):
public void removeLogin(Login[] array, String unwantedLogin, int loop)
{
for(int i=0;i<loop;i++)
{
String currentLogin = array[i].toString();
if(!currentLogin.equals(unwantedLogin))
{
Login login = new Login();
addLogin(array[i]);
}
}
}
plus 'addLogin' Method (although i am assured this is not the source of my issue):
public void addLogin(Login tempLogin)
{
listOfLogins[nextLogin] = tempLogin;
System.out.println(listOfLogins[nextLogin]);
nextLogin++;
System.out.println(nextLogin);
}
And the 'createLoginsTable' method:
public void createLoginsTable()
{
for(int i=0;list.nextLogin>i;i++)
{
loginTableLogins[i] = list.listOfLogins[i].toArray();
System.out.println(list.listOfLogins[i].toString());
}
JTable loginsTable = new JTable(loginTableLogins, loginTableTitles);
JScrollPane loginsScrollPane = new JScrollPane(loginsTable);
loginsScrollPane.setBounds(400, 200, 200, 250);
testPanel.add(loginsScrollPane);
}
I have used 'System.out.println's so I am 99% certain that the element has been removed from the array (it is also apparent through my writeLoginsToFile Method) So I hope this information helps.
Your code is a little bit hard to decipher, next time maybe put in also the enclosing class, or some details about that class. What does the following line do:
LoginList list = new LoginList(); //The 'list' is wiped
You say the list is wiped, I think what is does is: it declares a list local variable and assigns a new object to it (and it masks the other list variable which you used a few lines earlier). Now, in the createLoginsTable() method you don't have this local variable, you have the "list" which I guess is a public field in your class. Now what you can do, is or pass the local list variable to the above function as a parameter createLoginsTable(list) or try the wiping line without the declaration so only:
list = new LoginList(); //The 'list' is wiped
Anyway, your code seams a little bit troubled it, maybe you should refactor it a little bit. Hope it helps.
You're not returning the table after you delete the item.
When you call the method to delete it and write out the table, that table is not returned after you remake the table.
Take this:
JScrollPane loginsScrollPane = new JScrollPane(loginsTable);
Bring it outside of your method. What I think might be happening is when you create your loginsScrollPane locally inside the method, it's not being added properly to your testPanel.
I think what might be happening is when you add it, and the method ends it's loosing that data that is contained. Declare your scrollpane, and your jtable where you declare your frame.
I've been looking all over, and i cant find anyone who can solve this problem. I'm making a game, and in that game, i have editable controls. the controls window is a seperate JFrame, and when i click the confirm button, it is supposed to write the items in the JTextFields (holding the controls) to a file. but that wasnt working, so instead i have it print the arraylist that holds the values. here is the code:
public void writeControls() {
ArrayList<String> al = new ArrayList<String>();
al.add(up.getText());
al.add(down.getText());
al.add(left.getText());
al.add(right.getText());
al.add(jump.getText());
al.add(duck.getText());
al.add(attack.getText());
for (int i = 0; i < al.size(); i++) {
System.out.println(al.get(i));
}
System.exit(0);
}
the problem is this: if i change the final JTextField attack or any other one for that matter, and click submit, the system prints out the default controls. for example, if the JTextFields have the values w,a,s,d,r,t,q and i change the value q to i, it prints out q. what am i doing wrong? thanks in advance!
EDIT 1:
code for the textfields, and the FILES.... is simply a string stored in a different class. the class setText() is below the textfields.
up = new JTextField(setText(FILES.controlsFileFinalDir, 1));
down = new JTextField(setText(FILES.controlsFileFinalDir, 2));
left = new JTextField(setText(FILES.controlsFileFinalDir, 3));
right = new JTextField(setText(FILES.controlsFileFinalDir, 4));
jump = new JTextField(setText(FILES.controlsFileFinalDir, 5));
duck = new JTextField(setText(FILES.controlsFileFinalDir, 6));
attack = new JTextField(setText(FILES.controlsFileFinalDir, 7));
public String setText(String fileDir, int lineNum) {
String txt = "";
txt = io.readSpecificLine(fileDir, lineNum);
txt = switchCase(txt);
return txt;
}
switchcase() is only taking what you have written in the text file that these are getting the values from, and translating them. so if the value is 0, it is turned into Space, etc. io.readSpecificLine(); is only to get the line of text from the file. does this help?
EDIT 2:
i just was dinking around and found out that if i set the JTextField text by using setText(""); then use getText(); it works. so the problem is that when i change it manually, and use getText(); it wont work. Why?
To update the text to a currently existing JTextField, I would establish the JTextField as a class variable, and create a setter/getter method to adjust it (which I'm assuming you're doing).
According to your methods, you would use something like:
up.setText(setText(FILES.controlsFileFinalDir, 7));
Edit: **The first setText is the JTextField.setText, the second setText is your public method you posted. I'm assuming your second getText() isn't working because you're probably not setting the text correctly.
Without seeing more code, I can't really give a better guess.
The main possibilities:
(1) The text fields have their editable property set to false.
(2) You are creating multiple copies of the JTextFields, then editing a new one on the screen, but referring to the old one when you get the value.
(3) You have a ValueChanged or LostFocus event handler that is resetting the text fields to their defaults
(4) It is actually JFormattedTextField not a JTextField
If I was you, I would try to debug the programm. You will probably do some Mistake in your code, you won't be able to see, by just checking the code.
For example in which order do you call the functions and so on, maybe you have a fault here, or maybe you have several threads, so you try to read the Textfields without even set them and so on ... It's hard to say without reviewing the whole Code.
So if you use eclipse you can follow this link for an explanation on how to debug: http://www.vogella.com/articles/EclipseDebugging/article.html
Netbeans or any other IDE should support debugging as well.
This may seem like a strange thing to suggest, but I think this is an issue with pointers. If you create a new string before passing it in, JTextField will be able to change it internally and return what you expect when asked for the modified value.
down = new JTextField("" + setText(FILES.controlsFileFinalDir, 2));
// or
down = new JTextField(new String(setText(FILES.controlsFileFinalDir, 2)));
You might want to try the following:
create a class Test.java
import java.util.ArrayList;
import javax.swing.JTextField;
public class Test implements Runnable {
private ArrayList<JTextField> textFields = null;
private ArrayList<String> stringList = null;
public Test(ArrayList<JTextField> textFields, ArrayList<String> stringList) {
this.textFields = textFields;
this.stringList = stringList;
}
#Override
public void run() {
for ( JTextField textField : this.textFields )
this.stringList.add( textField.getText() );
}
}
and then, at the place where you use the "getText() method .. "
do the following...
ArrayList<JTextField> textFields = new ArrayList<JTextField>();
// add all the JTextField to textFields
ArrayList<String> stringList = new ArrayList<String>();
Test test = new Test( textFields, stringList );
SwingUtilities.invokeLater( test );
// check if the stringList is populated.
If this work, then what I believe is that, for some reason, the JTextField hasn't finished
"setting" the text, and before it finishes your getText() was called. I've had similar problems before, and this solved my problem that time, but still, this might not be the perfect solution.
First, you should change your "setText()" method name to something like "getTextFromFile()" it would be more readable
Then, if you are setting and reading the new text in different threads, my bet is that the setText() is taking long to return, because it is accessing the file system, while the method that read the values run instantly
I would try to do run a little test:
public void test(){ // must be run after the JTextFields be initialized
up.setText("TEST")
System.out.println(up.getText());
up.setText(setText(FILES.controlsFileFinalDir, 1));
System.out.println(up.getText());
}
If the test() prints the correct values, then we can assume that if you set and read the new value in the same thread it works fine
The other test I would do is:
public void testThread(){
new Thread(){
public void run(){
while(true){
if(up!=null){
System.out.println(up.getText());
}
try{
Thread.sleep(1000);
}catch(Exception e){
e.printStackTrace();
}
}
}
}.start();
}
It will print the value of up each 1 second, so that you can see if after some time you get the new value. If it does, then the answer is: Your setText() is taking long to run and you are reading the value before the new value is set
SOLUTION
none of the above answers were working for me, so i finally decided to just start over with that class. the few things i changed were the way i made the JTextFields. I made them as an array instead of individual objects. Second is the way i put what they say. When i initialized them, i was unable to get them to create WITH the text in the parameters. so i had to do that seperately. i changed some of the method names so as to reduce future confusion, and it worked! so im not sure what was up with that, maybe it was the way i did it, maybe just a fluke. it happens sometimes, so im sorry for the delay and waste of your time! thanks for all the answers anyway!
Try this:
textbox.setText(setFile(args)); // your function for set file