I've investigated lots of different questions and answers around this, but can't find one that seems to work.
I'm new to Java, but have experience in a variety of different languages and, so far (in context to what I'm experimenting with), it's feeling a bit like VBA except with having to build up the actions/functions that you feel should be already there. This is, I expect, just down to my own inexperience though.
I'm using Netbeans IDE 8.2 with Java Runtime 1.80.
I have created jFrame that contains a jTable. The jTable is built with data like so:
public void showTasks(Boolean removeID) {
ArrayList<Tasks> list = tasksList("SELECT * FROM tasks");
JTable table = jTable1;
DefaultTableModel model = (DefaultTableModel) jTable1.getModel();
Object[] row = new Object[4];
for(int i=0;i<list.size();i++) {
row[0]=list.get(i).getId();
row[1]=list.get(i).getName();
row[2]=list.get(i).getDesc();
row[3]=list.get(i).getDate();
model.addRow(row);
}
// Remove the 'id' column from the table view
if(removeID) { table.removeColumn(table.getColumnModel().getColumn(0)); }
}
The background behind this is less relevant, but essentially tasksList is a function that applies the query to an SQL statement, returning an ArrayList. I build up my rows with 4 columns, then remove the first column so 'ID' is available but not visible (this final action has been segregated through testing/experimentation).
I have another area of code that opens a jDialog when a row is clicked, in which it is possible to update the MySQL DB.
Problem
I'm trying to throw in a function call so that the table data 'refreshes' when the jDialog is closed. I have temporarily added in a button to the jFrame (where the jTable lives) to test/debug this function.
I can't seem to get this to work, though. The closest I have achieved is to re-call showTasks(false), but this obvious just adds rows with updated data, rather than replacing the dataset. I'm not 100% sure if deleting all the rows, then building them back in is 'best practice'.
As I'm new to Java, and may still be looking at it from a flawed method of thinking, I'm finding it difficult to apply any other examples to that of my own. I also can't seem to find a way to implement fireTableDataChanged().
Surely this is a simple concept I'm over-thinking?
Edit - based on below answer
Is there a reason why something like this would be considered incorrect, if deleting all rows and adding them back in is okay?
public void refreshTasks() {
DefaultTableModel model = (DefaultTableModel) jTable1.getModel();
int row_total = model.getRowCount();
for(int i= row_total -1;i>=0;i--) {
model.removeRow(i);
}
showTasks(false);
}
Edit: Button to invoke data update
Now works correctly (if not improperly) with the following:
private DefaultTableModel parentTable; // To store the parent 'Task' table model
public void setStart(int user,DefaultTableModel table) {
this.txt_taskID.setText(Integer.toString(user)); // Converts the ID to a string
addData(user); // Populates the fields
parentTable = table; // Sets parent TableModel to a variable
}
The above code is called from the Parent jFrame when the Dialog is opened, and passes the Table model and the 'ID' of the row I'm looking to edit. The table model is stored in parentTable.
There's also a 'Save' button, and a 'Cancel' button. I'm yet to separate these, and currently 'Save' does just that (SQL update and so on). My 'Cancel' button closes the dialog and refreshes the jTable, as per the below function:
private void btn_CancelActionPerformed(java.awt.event.ActionEvent evt) {
this.setVisible(false); // Hide the dialog
Menu menu = new Menu(); // for accessing the tasksList function
parentTable.setRowCount(0); // Clears the jTable data
// jTable data is then 'rebuilt' using the new data
ArrayList<Tasks> list = menu.tasksList("SELECT * FROM tasks");
Object[] row = new Object[4];
for(int i=0;i<list.size();i++) {
row[0]=list.get(i).getId();
row[1]=list.get(i).getName();
row[2]=list.get(i).getDesc();
row[3]=list.get(i).getDate();
parentTable.addRow(row);
}
}
I'm not 100% sure if deleting all the rows, then building them back in is 'best practice'.
Yes that is probably the best practice.
The only other approach is to create a completely new TableModel and add it to the table using the setModel() method. The problem with this approach is that it will reset any custom renderers/editors you may have set on the table.
The easiest way to remove all the rows from the DefaultTableModel is to just use:
model.setRowCount(0);
I'm not sure how you want to do it but I'm gonna give you simple example for deleting and refreshing JTable maybe it's help you.
This following btnDelete Jbutton added to JFrame for deleting rows from table:
btnDelete.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
int rowIndex = table.getSelectedRow();
if(rowIndex > -1) {
int x = (Integer) table.getModel().getValueAt(rowIndex, 0);
if (conn.removeContact(x) == true) { //here add your own code like removeID
model.removeRow(rowIndex);
lblInfo.setText("Contact deleted successfully.");
model.fireTableDataChanged();
} else {
lblInfo.setText("Cannot remove at this time!");
}
}else {
lblInfo.setText("At first you need select a row with single click!");
return;
}
}
});
and these following codes for refreshing table in primitive way :
btnRefresh.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
int rowCount = model.getRowCount();
for (int i = rowCount - 1; i >= 0; i--) {//remove all rows
model.removeRow(i);
}
lblInfo.setText("Table datas updated successfully.");
for (Person p : conn.readAllContacts()) {//add all row from scratch
model.addRow(new Object[] { p.getId(), p.getName(), p.getLastName(), p.getPhone(), p.getEmail() });
}
}
});
Related
I have a table that shows the results of user defined queries in a swing project. I want to allow the user to extract the data from a particular names column, if present. At the moment I can select the data from a column when I click the column but I don't know how to do the same thing from a button so that only a particular column's data (the column is called HNum) is obtainable. The code I have so far is as follows. If this is impossible I could always try to make sure that HNum is the first column but I need something cleaner I think.
btnCompare.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Object[] data_L = columnToArray(table,table.getSelectedColumn());
}
}
public Object[] columnToArray(JTable table, int columnIndex){
// get the row count
int rowCount = table.getModel().getRowCount();
// declare the array
Object [] data = new Object[rowCount];
// fetch the data
for(int i = 0; i < rowCount; i++){
data[i] = table.getModel().getValueAt(i, columnIndex);
}
return(data);
}
Do you tried to use a TableColumnModel ?
You can define all the treatment you need like a getColumnName{}
https://docs.oracle.com/javase/7/docs/api/javax/swing/table/TableColumnModel.html
edit :
an example
http://www.java2s.com/Tutorial/Java/0240__Swing/ExtendingAbstractTableModel.htm
Background
I have a JTable called table, and I have a column that is not part of the DefaultTableModel so its invisible:
final JTable table = new JTable(new DefaultTableModel(new Object[]{"Title", "Artist",
"Album", "Time"}, 0)
I add the respective rows like this:
int upTo = songList.size();
int idx = 0;
while (idx < upTo) {
SongObject curSong = songList.get(idx);
model.addRow(new Object[]{
curSong.toString(),
curSong.getArtist(),
"-",
curSong.getDuration(),
curSong});
idx++;
}
Where curSong is the the current song object that it is adding, the SongObject contains all data about the song. The toString() returns the title of the song.
Problem:
The problem is that when I try to access the column like this:
SongObject songToPlay = (SongObject) table.getModel().getValueAt(table.getSelectedRow(), 4);
It throws a java.lang.ArrayIndexOutOfBoundsException: 4 >= 4 exception.
Can anyone explain why and propose a solution?
Thanks in advance :)
DefaultTableModel.addRow() somewhere down the chain executes private justifyRows() method, which trims the unused columns from the row to the size equal to getColumnCount(). So the fifth column is never added to the model. As a result, you get ArrayIndexOutOfBoundsException when you're attempting to access this column.
If you need access to the actual SongObject then you can have a custom model that would return SongObject for a given row index. Make an extension of AbstractTableModel. See How to Use Tables tutorial for examples.
As an alternative, you can still use SongObject in a visible column. Just use a custom renderder that would renderer SongObject as a string for example. See Using Custom Renderers for details. You can reuse DefaultTableModel in this case.
Thanks to Aqua I overrode the following:
final JTable table = new JTable(new DefaultTableModel(new Object[]{"Title", "Artist", "Album", "Time"}, 0) {
#Override
public void addRow(Object[] rowData) {
Vector blah = DefaultTableModel.convertToVector(rowData);
insertRow(super.getRowCount(), blah);
}
#Override
public void insertRow(int row, Vector data) {
super.dataVector.insertElementAt(data, row);
super.fireTableRowsInserted(row, row);
}
});
Then I accessed the item in the fifth column (which is not part of the model!) like this:
SongObject songToPlay = (SongObject) table.getModel().getValueAt(table.convertRowIndexToModel(
table.getSelectedRow()), 4); //get the value at the VIEW location NOT THE MODEL collection
Sorry for the messy code but it worked. Home I could help someone with a similar problem. The solution just misses the justifyRows() method found in DefaultTableModel
I have a JTable which displays an Object[][] of data.
There is also a form on the same screen that lets the user add an item to the object to the list. Although for the life of me I can not get the list displayed in the table to update when the user presses the "Add Item" button.
(it gets appended to the array fine, and I can print it onto the screen, just can't get the table to change.)
Here is crating of the table
Object[] tableHeadings = {"Item Name","Qty/Weight","Price"};
ShoppingApplication shoppingApplication = new ShoppingApplication();
Object[][] tableData = shoppingApplication.generatePurchaseTableData();
final JTable tblBill = new JTable(tableData, tableHeadings);
Here is the table data being generated:
/**
* Generates data in the correct format to go into the table
* from the purchase list
* #return
*/
public Object[][] generatePurchaseTableData(){
Object[][] results = new Object[listOfPurchases.size()][2];
for (int i = 0; i<listOfPurchases.size(); i++){
Purchase purchase = listOfPurchases.get(i);
Object[] innerObject =
{purchase.getProductName(),
purchase.getPricePerUnit(),
purchase.getTotalPrice()};
results[i] = innerObject;
}
System.out.println(results.length);
return results;
}
}
Here's the action listener
/* Add Action Listeners */
cmdAddItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e){
AddPurchase addPurchase = new AddPurchase(
(radWeight.isSelected()) ? 'w' :(radQty.isSelected()) ? 'q' : 'u',
txtNameOfItem.getText(),
txtAmount.getText(),
txtUnits.getText(),
txtPricePerUnit.getText());
ShoppingApplication sa = new ShoppingApplication();
Object[][] newData = sa.generatePurchaseTableData();
//TODO make tblBill updata it's contents
}
});
From the code above, it does look like I haven't made much effort, but I've actually been trying to get this to work for hours now, tried using different methods, data structures and been getting no where to went right back to the start, and that is what the above code it.
I've Googled this a bit, and can't seem to find anything, can't think why no one else has seemed to get stuck on this. (maybe I'm just being thick) but hopefully this post will help others too.
Thanks in advance :)
The JTable has a data model (TableModel), which either holds the values, or is an adapter to the actual data.
Data in a table can be update by either changing the data in the table model, or by setting a new table model.
In your case, you could use the javax.swing.table.DefaultTableModel:
TableModel tableModel=new DefaultTableModel(newData, tableHeadings);
tblBill.setModel(tableModel);
update when the user presses the "Add Item" button.
Why do recreate the entire table when you only add a single item? That is not very efficient.
Instead must add a new row to the table. This code (like the above code) assumes you are using the DefaultTableModel:
DefaultTableModel model = (DefaultTableModel)table.getModel();
model.addRow(...);
ive been trying to update the table after the insertion or deletion of items from a abstract table model but whenever i do that, instead of removing the old records and replace with the new ones, the old rows remains and it creates all the rows again without removing the old ones..so i get duplicate items, this is the code im using :
for the data inserted :
TestModel tm = new TestModel() ;
tm.fireTableRowsInserted(records.length, records.length);
and for the data deleted :
TestModel tm = new TestModel() ;
tm.fireTableRowsDeleted(records.length, records.length);
any clue of how to get around with that?
any help is greatly appreciated!
Kind regards,
Romulo Romero
Create a table with a boolean column. Since using this boolean column you can delete those rows that are selected for deletion. Just like the following screen shot,
Then in your TableModel make a List<StudentDO> such that it will hold all the table data.
Adding a Row:
To add a row just create a new StudentDO and send it to the table model and the model addRow method will add the object to the table list.
Deleting Rows:
For Deleting rows just call a delete method and this should fire event in TableModel such that model should traverse all the rows and check which ever row is selected and delete it.
Note: Deleting rows should be done from the end not from the beginning of the list.
StudentTableModel.java
class StudentTableModel {
// Required methods code goes here.
public void addRow(StudentDO do1) {
data.add(do1);
fireTableRowsInserted(getRowCount() - 1, getRowCount() - 1);
}
public void deleteRow() {
for(int rowIndex = data.size() - 1; rowIndex >= 0; rowIndex--) {
if(data.get(rowIndex).isSelect()) {
data.remove(rowIndex);
}
}
fireTableDataChanged();
}
}
P.S: fireXXXMethods should be called only in the model. Because any data change will be responsible of the model.
I have a JTable in my program. I want to update it after clicking JButton.
I wrote this:
DefaultTableModel myTable = new DefaultTableModel(celDatas,celNames);
JTable source = new JTable(myTable){public boolean isCellEditable(int rowIndex, int colIndex) {
return false;}};
JScrollPane pane = new JScrollPane(source);
(...)
start.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
query = "Select sal FROM EMP";
myTable =(DefaultTableModel)source.getModel();
myTable.fireTableDataChanged();
}
The problem is that id doesn't update my data on JTable.
How to resolve this problem?
EDIT:
JTable is displayed in my guy through JScrollPane.
I make now this:
source = new JTable(myTable){public boolean isCellEditable(int rowIndex, int colIndex) {return false;}};
pane = new JScrollPane(source);
I made also a new void, where is getting datas from database + there I define myTable:
void queryConnection() {
(...)
myTable = new DefaultTableModel(celDatas,celNames);
}
I added a JButton, which update my JTable (when we change the query.
start.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
query = "Select sal FROM EMP";
queryConnection();
}
}
================================================================================
public class Application2 implements Runnable {
private JTable source;
private JScrollPane pane;
private DefaultTableModel myTable;
private JPanel panel;
private String[][] celDatas = null;
private String[] celNames = null;
public void run() {
(...)
start.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
if(...) {
query = "Select sal FROM EMP";
queryConnection();
}
}
if(query == null) {
query = "Select * from EMP";
queryConnection();
}
source = new JTable(myTable){public boolean isCellEditable(int rowIndex, int colIndex) {return false;}};
pane = new JScrollPane(source);
pane.setSize(f.getSize().width-60,300);
pane.setLocation(30,20);
panel.add(pane);
f.add(panel);
f.pack();
}
void queryConnection() {
//here is connection and downloading datas
myTable = new DefaultTableModel(celDatas,celNames);
}
I hope that it is right now more convenient? ;)
You don't need to call any fireXXX() methods if you're creating a new TableModel, but rather you mainly need to call these if you're writing your TableModel based on AbstractTableModel (you're not).
Your problem lies elsewhere I think. You seem to be creating a new JTable and adding it to a new JScrollPane. Are you adding these components to your GUI (you don't show)? If so, is the container that you're adding to able to accept new components smoothly? Do you revalidate and repaint the container? Is your newly created JTable being displayed in the GUI?
Or, is there a JTable already displayed in your GUI? If so, perhaps all you want to do is set its model rather create a new JTable. I favor this solution as the easiest.
Edit 1
I would do something like so:
Access Database in a background thread and get information from it.
Create a new DefaultTableModel object filling it with data extracted from the database.
I would not create a new JTable if one already exists. Instead I'd simply call setTableModel(...) on the currently displayed JTable and pass in my newly created DefaultTableModel object.
Then I'd sit back and enjoy the big bucks and other fruits of my success.
Edit 2
Ganjira, for us to be able to best help you, we need to understand the problem better, which is why I've requested either full clarification of your problem or an sscce, of which I've seen neither. My problems with understanding your issues include:
Again, do you have a JTable already displayed in your GUI, and now you're trying to change the data that is displayed in the JTable based on data extracted from a database?
If so, why not simply change the model of the existing JTable rather than create a whole new JTable?
If you don't already have a JTable in the application and now you want to display one, you state that your data is not being displayed but don't show code to help us understand why.
If you can answer the first two questions, we may not need an sscce, but if not, please understand that your current post is no where close to being an sscce, in that we cannot run it, we cannot compile it, it doesn't reproduce your problem for us,... I have to wonder if you've even read the link yet as it explains why all of these conditions are important (that and brevity so as not to drown us in a large amount of unrelated code).
No, it is not required that you post an SSCCE, but if we can't help you based on the text in your question and your code snippets, it does offer a better chance of allowing us to understand the problem and find a solution for you.
Edit 3
You state:
JTable's been already in GUI, because it shows the 'beginning of the program'. After clicking JButton I want to change values in JTable. It doesn't change the model of the existing JTable - it doesn't change nothing.
And this confuses me as the best solution is one I've been suggesting all along -- Don't make a new JTable, but instead create a new DefaultTableModel and change the model for the existing JTable. You've yet to mention why you're not trying this, or if you have tried it, how it's not working for you.