I am using a table to display data.
I am providing checkbox to each row of a table to perform some operations based on selection. When I did like that, I am able to check multiple rows.
But my requirement is, at any point of time I should check only one checkbox. To be precise, I need the behavior of Buttongroup to all checkboxes in table.
How can I do this?
If you really want to use checkboxes, I assume your TableModel holds a boolean for those checkboxes. It should be trivial to move the logic for the single selection to the TableModel.
If you do not need the checkboxes but just want to operate on the selected rows (see JTable#getSelectedRows), you can adjust the ListSelectionModel which is present on the JTable to only allow for single selection (see ListSelectionModel#SINGLE_SELECTION)
CheckOne is a complete example that simply clears all check boxes in a specific column and sets the new value. This related example uses JRadioButton.
Related
I just got this Jtable on Netbeans . First I want it to auto-calculate some grades, as you can see it has 3 columns (1st, 2nd and 3rd evaluation). I have to type between 0 and 100, in each row.
In the end, get the total and average. This can be displayed in a Jlabel, or a textfield. But, it has to be displayed real-time (as I'm typing the values).
Also, I can't type data on all the cells, just one for each row. How do I do this?
I know I can change the columns to accept only Integer values, but for everything else, I have no idea how to proceed.
In the end, get the total and average. This can be displayed in a Jlabel, or a textfield. But, it has to be displayed real-time (as I'm typing the values).
Well, you would want to update "after" the user has finished editing a cell and saves the value to the table.
So you can use a TableModelListener. You add the TableModelListener to the TableModel. Then when the data is saved an event will be generated and you can recalculate the values and update the label.
Check out the following for a simple example to get your started: TableModelListener and multiple column validation. Your logic in the listener will change based on your exact requirement.
You can do this by attaching a defaultTableModel to your JTable. After attaching TableModel to your JTable. You can use command JTable.addRow(Object[]) to add rows to table.
A JTable displays data from an array of objects. Object data changes in the background and the table is updated. When rows are selected and the table data changes the row selections are lost. It is difficult for the user to select rows for an action when the selections are frequently lost.
Is there a way to stop the deselection?
Here's what I found using the debugger. The row selection is being cleared during the call to fireTableDataChanged, which I was using to apply the updates in the table.
Apparently that method redraws the table and the selection may not be valid (as suggested by the MadProgrammer comment above). I will still be needing that feature when objects (rows) are be added or removed.
So what I must do is find a way to notify the table model to make updates to without clearing the selection. I have chosen for now to use fireTableRowsUpdated when updates are to be applied that do not require restructuring the table and fireTableDataChanged otherwise.
I have a JTable. One column in the JTable is assigned an extended TableCellEditor that displays an extended JComboBox.
There is a fixed list of 100 String objects that populates the comboboxes.
The challenge:
Design the JComboBoxes so that any selection is unique relative to other boxes? That is, if "A" is slected from the combobox in the first row, it is automatically removed from the list of each other combobox.
When a new room is added to the table, the combobox it contains should auto-populate to the first available list item.
The problem:
My comboboxes work beautifully. I can select items at will. I even have made some progress in eliminating already used items from the lists. But I can't figure out how to correctly auto-populate.
I am very confused because it appears that my combobox constructor is only called once when the table is created, not once for each row.
Is this the case? Is the constructor for a TableCellEditor only called once ever? If so, how do I modify the behavior of each combobox as it come into existence?
Thanks for your help!
If you would like specific code, please let me know. I don't know if you want me to paste in the whole classes.
When a new room is added to the table, the combobox it contains should auto-populate to the first available list item.
When you add a new row of data to the TableModel you must add the values of all columns in the row. This should not be a function of the editor. The editor allows you to change values in the cell.
I was able to get around my problem by creating an abstract superclass for my combobox that can be accessed from the tablemodel extension when it sets up its data.
I want to put subject results in a Jtable. I set DefaultTableModel to the table. In my table I have three columns.Student ID,Marks and Grade.Student ID is auto generated in column one.then user should enter marks for for second column.Then I want to automatically put the necessary grading in 3rd column.I load the grading data from the database and find the correct grading for the marks.I try this with both MouseReleaseEvent and KeyReleaseEvent.But it wasn't successful.Can any one suggest me a better way.thank you.
You don't have to listen for the input events, because the table has cell editors already. So you should be capable of editing your table. The only thing you need to do is to listen for the tableChanged event and update the database there.
See: TableModelListener
In case I was confused by your thoughts about the events and you just want to basically set values of a cell programmatically, try this method: setValueAt(Object,int,int)
I have a 2D array of objects which needs to be displayed in a table through a table model class which extends a DefaultTableModel. In addition to the columns needed to accommodate the data included in this array, I would like to add an extra column with radiobuttons, in order to enable the user to make a selection. As table model accepts only arrays of objects or vectors, how should I add radio buttons?
By default, JTable infers how to render and edit entries based on the entry's class, as discussed in the tutorial article Editors and Renderers. In this example, a checkbox allows multiple selections in a column. Substituting a radio button and using a ButtonGroup would accommodate a unique selection.