Develop Reference

Java - Swing form appear empty when get called

I got a mouse click event that call and display a new JFrame form when click. But when I click, the form show up with no element inside it. There are 2 events of that type in my project and I handle them both with the same mechanism. The first one works perfectly, but the second one got the problem. I also use pack() but the problem is still there. Could any one show me how to work this out? Thanks a lot! My project is in Vietnamese, so if any one wants to mention any element in the code or the UI, just writing it with no sign is good enough!
Here are the event handlers:
//The first event
private void tblClientResultMouseClicked(java.awt.event.MouseEvent evt) {
// TODO add your handling code here:
DefaultTableModel dm = (DefaultTableModel) tblClientResult.getModel();
int row = tblClientResult.getSelectedRow();
int col = tblClientResult.getSelectedColumn();
if (col == 7) {
SearchTruyenFrm searchTruyenFrm = new SearchTruyenFrm(listKH.get(row));
searchTruyenFrm.setVisible(true);
}
}
//The second one
private void tblTruyenResultMouseClicked(java.awt.event.MouseEvent evt) {
// TODO add your handling code here:
DefaultTableModel dm = (DefaultTableModel) tblTruyenResult.getModel();
int row = tblTruyenResult.getSelectedRow();
int col = tblTruyenResult.getSelectedColumn();
if (col == 6) {
MuonTruyen muonTruyen = new MuonTruyen();
muonTruyen.setTruyen(listTruyen.get(row));
muonTruyen.setPhieuMuon(phieuMuon);
//Trouble here (?)
ThueTruyenInfoFrm infoFrm = new ThueTruyenInfoFrm(listTruyen.get(row));
infoFrm.setVisible(true);
while (infoFrm.isVisible()) {
}
muonTruyen.setDieuKien(infoFrm.getTxtDieuKien().getText());
muonTruyen.setGiaMuon(Float.parseFloat(infoFrm.getTxtGiaThue().getText()));
muonTruyen.setTienPhat(0);
muonTruyen.setPaid(false);
}
}
Inside the constructor:
public ThueTruyenInfoFrm(Truyen selected) {
initComponents();
txtTenTr.setText(selected.getTen());
txtTacGia.setText(selected.getTacGia());
pack();
}
How it happens:
Desired outcome:

Welcome to the wonderful world of "Honey, I've blocked the Event Dispatching Thread (and now nothing works)"
Mouse events (like all GUI based events) are delivered within the context of the EDT, so doing something like...
private void tblTruyenResultMouseClicked(java.awt.event.MouseEvent evt) {
//....
while (infoFrm.isVisible()) {
}
}
will block the EDT and prevent any further processing of events, including paint events, basically hanging your program.
I suggest you start by having a read of The Event Dispatch Thread to get a nutter understand of the overall issue.
To solve your problem, you will want to make use of a modal dialog, which will wait at the point the dialog is made visible and continue executing after it's closed.
Have a look at How to make dialogs.
This is an important lesson, as you should never start with a top level container (like JFrame), but instead, base all you GUIs on something like a JPanel instead, this gives you greater freedom in deciding on when and how those components are displayed.
Form editors won't teach you techniques which produce re-usable or self contained code and I would highly recommend that you consider spending sometime coding them by hand.

simplier way to add jbutton to jtable

well i am making this system that has a table, and i have to put buttons in the last column. i've been researching but all the codes i saw are really confusing. there is one tho, but there are still some parts that i didn't understand. here's the site where i got it http://www.javaquery.com/2013/05/how-to-implement-jbutton-in-jtable.html
String[] InvoiceArray = new String[20];
//Declare above variable globally. Used by two-three methods. Change variable name as per your need.
/*
* import the ButtonColumn class if you are not working in IDE
* I used formWindowOpened event to load content in Jtable but you can use other event.
* All you need is put the code with in that event.
*/
private void formWindowOpened(java.awt.event.WindowEvent evt) {
Object[][] rowData = new Object[4][2]; // 4: is number of row ; 2: is number of column
Object columnNames[] = {"Invoice No", "View Report"}; // Name of columns
for (int i = 0; i < 4; i++) {
InvoiceArray[i] = i + "-2345";
rowData[i][0] = i + "-2345";
rowData[i][1] = "View Order " + i; // Can change the text of button.
}
DefaultTableModel tm = new DefaultTableModel(rowData, columnNames);
jTable1.setModel(tm);
ButtonColumn buttonColumn = new ButtonColumn(jTable1, showOrder, 1); // 1: is column number. column count starts with 0,1,2...
}
what's the InvoiceArray for? and should i make the showOrder from the last line? and also, i didn't understand the code he posted on how to make a listener on it. here it is:
Action showOrder = new AbstractAction() {
public void actionPerformed(ActionEvent e) {
//JTable table = (JTable) e.getSource(); // If you have multiple component following the ActionEvent
int modelRow = Integer.valueOf(e.getActionCommand());
if (InvoiceArray[modelRow] != null) {
/* We are placing invoice no in array
* And track the button click index
* And fetch index in invoice no
*/
System.out.println("Your Invoice No:" + InvoiceArray[modelRow]);
} else {
JOptionPane.showMessageDialog(rootPane, "No records found!");
}
}
};
i know there are some explanations already. i understand some of them but not all. just a simplier way to add jbutton on jtable and also listeners for the jbutton. thank you so much

just a simplier way to add jbutton on jtable and also listeners for the jbutton.
There is no simple way. You need to understand how renderers and editors work in a JTable. Read the section from the Swing tutorial on Concepts: Renderers and Editors for the basics.
Then you can check out Table Button Column which does the hard work for you. You only need to provide the Action to be invoked when you click on the button.
what's the InvoiceArray for?
It is used to load data into the JTable. This is basic usage of a JTable and has absolutely nothing to do with adding a button to a column of the table.
After the data is loaded you should forget about the invoiceArray. The Action you write should access the data via the TableModel or the JTable.

JTable with 2 different data

Im using a JTable , loading on it a different data depending on the button pressed.
The problem is : when one of the data is loaded, if i try to load the other one, and pass ther mouse over the header or a cell, it updates the header/cell with the data from the first input, if there is data on the header/cell selected.
Any ideas on how to solve it? That's the code im using.
private static void setCompromissosTable(Object[][] data, Object[] header){
try{
compromissosTable.removeAll();
} catch(Exception e){
e.printStackTrace();
}
compromissosTable = new JTable(data, header);
compromissosTable.setRowSelectionAllowed(true);
// Make the entire row selectable, but not editable
int columnMax = compromissosTable.getColumnCount();
for(int column = 0; column < columnMax; column++){
Class<?> col_class = compromissosTable.getColumnClass(column);
compromissosTable.setDefaultEditor(col_class, null);
}
scrollPane = new JScrollPane(compromissosTable);
pane.add(scrollPane);
scrollPane.setBounds(btnAddCompromisso.getX(),
btnAddCompromisso.getHeight() + btnAddCompromisso.getY() + 5
, frame1.getWidth() - 20
, frame1.getHeight() - 20);
compromissosTable.revalidate();
compromissosTable.repaint();
compromissosTable.addMouseListener(new MouseAdapter() {}
//Change mouse behavior.
);
}

This is suspicious...
compromissosTable = new JTable(data, header);
//...
scrollPane = new JScrollPane(compromissosTable);
pane.add(scrollPane);
Basically, assuming that each time you want to switch data sets, you are calling this method, you are creating a new JTable and JScrollPane each time and then are adding it onto the UI...
What about the previous JTable?
Next is this...
scrollPane.setBounds(btnAddCompromisso.getX(),
btnAddCompromisso.getHeight() + btnAddCompromisso.getY() + 5
, frame1.getWidth() - 20
, frame1.getHeight() - 20);
This looks like you're using a null layout. Basically what it "looks" like is happening, is you're just stacking the JScrollPanes ontop of each other, which would explain, in part, the graphics glitches, as the components are actually been added at the same z-deepthness (essentially) and are competing with each other then they are updated.
Two simple answers...
Don't use null layouts. Sure they "seem" like a good idea, but they have a tendency to turn around and bite you in strange and wonderful ways which are hard to diagnose and fix. Use the layout management API which Swing was designed around
Update the JTables model instead of creating a new JTable/JScrollPane each time
See How to use tables and Laying Out Components Within a Container

Handling events for a collection of JButtons

I'm attempting to create dynamic interface that essentially creates a grid of a growing number of panels that look similar to the picture below. I've got some rough code to achieve that. I have an issue in regards to handling events for the JButtons that i've added to an ArrayList. I'm aware that creating inner class event handlers is best practise, how would I handle events for a scaling number of buttons that are stored in an ArrayList?
Currently i've resulted to getting the objects source to achieve this.
Global Variables:
ArrayList<JButton> buttons = new ArrayList<JButton>();
Adding buttons to the panel:
for (int i = 0; i < 2; i ++) {
int xTotal = 150;
if (i == 0) {
xTotal = 132;
}
else {
xTotal = 308;
}
xTotal = xTotal + xTotal;
JButton currentButton = new JButton("+");
currentButton.setBounds(xTotal , 375, 45, 25);
currentButton.setFont(currentButton.getFont().deriveFont(14f));
currentButton.addActionListener(new AddHandler());
buttons.add(currentButton);
panel.add(currentButton);
}
Event handler:
class AddHandler implements ActionListener {
public void actionPerformed(ActionEvent event) {
Object source = event.getSource();
if (source == buttons.get(0)) {
System.out.println("hello");
}
else {
System.out.println("it worked");
}
}
}

It looks to me like you're creating more than just a collection of JButtons. Instead you appear to be wanting to create (and correct me if I'm wrong), a collection of images/text with JButton. This suggests that you want to create a class that encapsulates one (?) menu item, that holds a JLabel for the image, a JLabel perhaps for the text, perhaps other components, and a JButton that the user can press to select the menu item. This component would be a JPanel that (important here) uses layout managers to intelligently arrange all of its constituent components. I would recommend not using ActionListeners but rather create a separate stand along class that extends AbstractAction, that you can use to set each JButton's Action, either via the JButton's constructor or via its setAction(...) method. Then you could place a collection of these JPanels in a master JPanel that uses perhaps a GridLayout, and have it held in a JScrollPane.
The details of my suggestions and the code would of course depend on the details of your GUI and your current code.
Other "side" recommendations:
Don't use null layouts and setBounds(...). Often newbie Swing programmers feel that this is the easiest way to create complex GUI's, and in the short term it may be, but in the long term, when it comes time to maintain, upgrade and enhance your GUI, it isn't. Also the GUI's so created may look OK on one platform and screen resolution, but they look terrible on all others. Learn about and use the layout managers.
Maybe you want a collection of Actions or the JButtons, but I'm not sure you need this. If the button's Action knows what to do, then no collection is needed. The Action could have a constructor that passes in references to the name and price of the menu item.

Even though youve already accepted another answer, I want to share what I have on my mind.
The idea of my idea is to store a number (maybe an ID) on the button by creating a subclass of JButton.
(ID could be, perhaps the ID of the food item this button is currently linked to)
class FoodButton extends JButton{
long id;
public FoodButton(String text, long id){
super(text);
this.id = id;
}
//Perhaps more constructors
public long getId(){
return id;
}
}
Then writing a single actionListener that gets the source of the event (even though you seem to think thats bad practice, I think it makes sense in this example), Observe:
ActionListener al = new ActionListener(){
#Override
public void actionPerformed(ActionEvent e){
FoodButton btn = (FoodButton) e.getSource();
long id = btn.getId();
//Do something now that you know what button was clicked (id)
}
}
Let me note again that this actionListener is created before your loop, so you only need one, and you'll assign the same one to all your buttons.
Then inside your loop instead of creating a normal JButton, you create a FoodButton:
ActionListener al = new ActionListener(){...};
for (int i = 0; i < 2; i ++) {
//...
//Assigning id 'i' here, but you could pick something else
JButton currentButton = new FoodButton("+", i);
//...
currentButton.addActionListener(al);
buttons.add(currentButton);
panel.add(currentButton);
}
I hope this makes some sense to you.
Also, as someone who used to use null layouts too, once you get accustomed to using layoutmanagers, im sure you will like them.

JComboBox is refering to old Frame while removeAllItems()

I tried to figure this out myself but I can't. I'm stuck at a strange problem.
I have a Java Program with multiple classes and forms (I use Intellij and the build in GUI-Creator). When I switch from one Screen to another I just call frame.setVisible(false); at the leafing window and frame.setVisible(true); at the window I want to show next.
On a Button Click I make this:
In Class 1:
if (e.getSource() == umschaltenButton) {
this.mainW.goToMainWindow();
logger.log(Level.INFO, "Switched Back to MainMenu");
frame.setVisible(false);
}
And here is the weird part.
In Class 2:
public void goToMainWindow() {
frame = tvElectronics.drawMainWindow(); // I get a new Frame with new Images and so on
frame.addMouseListener(al);
frame.add(BotomPanel); // in here is the JComboBox
frame.setSize(LENGTH, HEIGHT);
comboBox1.removeAllItems(); // Here it tryes to refere to the old frame before i made frame = tvElectronics.drawMainWindow();
Vector<String[]> content = tvElectronics.getContent();
for (int i = 0; i < tvElectronics.getAnz(); ++i) {
comboBox1.addItem((i + 1) + ". " + content.get(i)[3]);
}
comboBox1.setSelectedIndex(chanel);
frame.setVisible(true);
}
And so it tries to update the old frame from class2 which no longer exists because of the new one I just created. And so I have 2 frames open: one as I want it and one strange old frame form class2.
My problem is that I want bind my JComboBox to a new Frame and update it but it is still connected to the old one and that causes weird problems like jumping back in the function. I mean it is at the last line of goToMainWindow() and then it starts again at the first line.

First off you should avoid swapping JFrames as your program does since this is a very annoying GUI design. Please read The Use of Multiple JFrames, Good/Bad Practice? for more on this.
Next, it's impossible for us to tell what GUI view your JComboBox is associated with.
But having said that, it really shouldn't matter. Instead of doing what you're doing, I would give the display class that holds a JCombBox a public method that you call on the containing display class that clears the contained JComboBox's model or that places items in the model. This way, there will be no ambiguity as to which JComboBox you're referring to, and this way you avoid directly exposing a view's inner components.
As an aside, I try to gear my display or view classes towards creating JPanels, not JFrames as this will give my code much greater flexibility.
For example
// my display class
class Display1 {
private DefaultComboBoxModel<String> myModel = new DefaultComboBoxModel<>();
private JComboBox<String> myCombo = new JComboBox<>(myModel);
public void removeAllComboElements() {
myModel.removeAllElements();
}
public void addElement(String ele) {
myModel.addElement(ele);
}
}
Same for your Display2 class. Then you can call the correct method on the JComboBox that is held by the correct view/display.
This way, when you swap displays, perhaps by using a CardLayout, you can clear the JComboBox in the display that is being shown by calling its own method to clear its own combobox's model.