So my issue that I have is implementing a functioning delete button for my GUI.
While I have just about everything working, I have been stumped with trying to implement this function. What it does is as i click the 'Add' button, it creates a row with text fields and a check box. The 'Delete' works in the sense that it only deletes the most recent field create once I click on the checkbox to delete it. My intention is that the GUI works in a dynamic way to where I can click whatever check boxes and delete only those specific rows with the boxes checked.
I've researched methods of using an ItemListener but I'm still wrestling with that as I figure its the most proficient way to go. I've also done the storing the components in an array to iterate over. I feel I'm close with what I have now, any advice appreciated.
Below is the 'Add' button code to create new rows in my GUI. Then there is the 'Delete' button code which places the components in an array, but only deletes the most recent row created that has been checked.
add = new JButton("Add");
add.addActionListener(e ->{
rowPanel = new JPanel(new GridLayout(1,4,5,5));
for(int i = 0; i < 4; i++ ){
rowPanel.add(new JTextField(8));
}
for(int l=0; l < 1; l++){
rowPanel.add(new JCheckBox(), BorderLayout.EAST);
}
infoPanel.add(rowPanel);
infoPanel.revalidate();
infoPanel.repaint();
});
delete = new JButton("Delete");
delete.addActionListener(e -> {
Component[] components = rowPanel.getComponents();
for(Component c : components){
if(c instanceof JCheckBox){
if(((JCheckBox)c).isSelected()){
infoPanel.remove(rowPanel);
}
}
}
infoPanel.revalidate();
infoPanel.repaint();
});
You can use a JTable as a container and add a custom row that is a checkbox and a textfield. This way you just have to get the checkbox's event and see what index in the JTable it is located and delete it.
This might be useful:
https://docs.oracle.com/javase/tutorial/uiswing/components/table.html#editrender
Related
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.
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
I've created a JTable whose columns contain a variety of different components. The last five columns either contain nothing (a DefaultTableCellRenderer with no value) or a JRadioButton using a custom renderer and editor. The renderer creates and returns a new radioButton in the cells I need one, and I want to access these radio buttons from my panel class to add them to a ButtonGroup. I am using the following piece of code that I wrote:
protected void setButtonGroups() {
buttonGroups = new ArrayList<ButtonGroup>();
for (int i = 0; i < tableModel.getRowCount(); i++) {
ButtonGroup currentGroup = new ButtonGroup();
for (int j = 0; j < tableModel.getColumnCount(); j++) {
if (table.getComponentAt(i, j) != null) {
currentGroup.add((JRadioButton)table.getComponentAt(i, j));
}
}
}
buttonGroups.add(currentGroup);
}
}
getComponentAt() keeps returning null regardless of what is contained in the cell, whether it be a JCheckBox, JRadioButton, JComboBox... everything is returned as null.
Is there an alternative way to get the cell's component? Or is there a way for me to get this to work? Thank you!
If you have a tableModel from table.getModel(). Then you can call model.getValueAt(row,col)
I am not sure why you are putting Swing Components inside a JTable. Are you using it for formatting? If so look into LayoutManagers. If you want to edit values in a table, you might want to look into extending TableCellEditor. If you really want to put components in your table. Consider extending the DefaultTableCellRenderer to return your component. You will want to override getTableCellRendererComponent().
I'm trying to make a simple calculator in Java using Swing, and I've created my buttons the following way:
//Our number keypad
public static JPanel numbers(){
//our panel to return
JPanel panel = new JPanel();
//Create and add 3x4 grid layout to panel
GridLayout gl = new GridLayout(3, 4);
panel.setLayout(gl);
//For creating and adding buttons to panel
for(int i = 0; i < 10; i++){
//Create a new button where the name is the value of i
String name = "" + i + "";
JButton button = new JButton(name);
//add action listener
button.addActionListener(handler);
//Add button to panel
panel.add(button);
}
return panel;
}
My question is how do I reference each specific button in my event handler? I can't think of a way to do this without having to manually create each button rather than using a loop.
Thanks.
In your listener, call event.getSource(), and that will return the button which has been pressed. Get the text of the button, and you have its number.
Or create a different instance of your handler for every button, and pass the value of the button (i) to the constructor of the handler. This last solution is cleaner, IMO, because it doesn't depend on the text of the button. If you replaced the text by an image, for example, the first technique wouldn't work anymore.
You can distinguish created buttons by adding the following inside handler:
String buttonText = ((JButton) e.getSource()).getText();
if (<text1>.equals(buttonText)){
//do the stuff
} else if (<text2>.equals(buttonText)){
//do the stuff
} else {
//do the stuff
}
Method #1: go through the child components of the parent JPanel (quite tedious, has to be rebuilt every time you modify the contents of that JPanel). Make sure they're JButtons by using an if . . instanceof clause.
Method #2: as you create them in that loop, add them to a List (or even better, a Map). I prefer a Map personally as it lets me customise the key for that specific JComponent
i.e.
HashMap<String, JComponent> buttonList = new HashMap<String, JComponent>();
for(. .) {
buttonList.put("nameForEachButton", button);
}
I recommend generating the button name based off of the loop counter. Either use your existing name value, or just set it to "button" + i;
Declare your buttons using an array.
JButton[] button = new JButton[9]; //outside the for loop
for (int i = 0; i < 10; i++) {
//put your code
button[i] = new JButton(name);
//your code
}
I'm very new to Java and am having some issues looping through JCheckBoxes on a UI. The idea is that I have a bunch of checkboxes (not in a group because more than one can be selected.) When I click a JButton, I want to build a string containing the text from each selected checkbox. The issue I'm having is that our instructor told us that the checkboxes need to be created via a method, which means (see code below) that there isn't a discrete instance name for each checkbox. If there were, I could say something like
if(checkBox1.isSelected()) {
myString.append(checkBox.getText());
}
That would repeat for checkBox2, checkBox3, and so on. But the method provided to us for adding checkboxes to a panel looks like this:
public class CheckBoxPanel extends JPanel {
private static final long serialVersionUID = 1L;
public CheckBoxPanel(String title, String... options) {
setBorder(BorderFactory.createTitledBorder(BorderFactory
.createEtchedBorder(), title));
setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
// make one checkbox for each option
for (String option : options) {
JCheckBox b = new JCheckBox(option);
b.setActionCommand(option);
add(b);
}
}
}
This is called like this:
toppingPanel = new CheckBoxPanel("Each Topping $1.50", "Tomato", "Green Pepper",
"Black Olives", "Mushrooms", "Extra Cheese",
"Pepperoni", "Sausage");
So I now have a panel that contains a border with the title "Each Topping $1.50", and 7 visible checkboxes. What I need to do is get a list of all the selected toppings. We are not supposed to use an ActionListener for each checkbox, but rather get the list when a button is clicked. I'm feeling really clueless here, but I just can't figure out how to get the isSelected property of the checkboxes when the individual checkboxes don't have instance names.
Ideally I'd like to somehow add all the checkboxes to an array and loop through the array in the button's action listener to determine which ones are checked, but if I have to check each one individually I will. I just can't figure out how to refer to an individual checkbox when they've been created dynamically.
I'm assuming you're not allowed to alter the CheckBoxPanel code at all. Which seems like a useless exercise, because in the real world, you'd think that if CheckBoxPanel where a class being provided to you (e.g. in a library) it would include a way of getting the selected options. Anyway, due to the limitation, you could do something like this:
for( int i=0; i<checkBoxPanel.getComponentCount(); i++ ) {
JCheckBox checkBox = (JCheckBox)checkBoxPanel.getComponent( i );
if( checkBox.isSelected() ) {
String option = checkBox.getText();
// append text, etc
}
}
I suggest you maintain a list of checkboxes:
List<JCheckBox> checkboxes = new ArrayList<JCheckBox>();
and before add(b) do:
checkboxes.add(b);
You may then iterate through the list of checkboxes in the buttons action-code using a "for-each" loop construct:
for (JCheckBox cb : checkboxes)
if (cb.isSelected())
process(cb.getText()); // or whatever.
Alternatively, if you need to keep track of the specific index:
for (int i = 0; i < checkboxes.size(); i++)
if (checkboxes.get(i).isSelected())
....
I would suggest that you dont put each of the checkboxes in a List when you create them. Instead, in your shared ActionListener, you maintain a Set of all selected checkboxes. Use the getSource method on the ActionEvent to identify which checkbox the user selected and then cast it to a JCheckBox. If isSelected() returns true for the item in question, attempt to add it to your selectedItems Set. If it is not, then attempt to remove it.
You can then just iterate over the subset of all items (only those that are selected) and print them to the console.