I am a newbie to Swings
Can some on please help me
I have a scenario: in which I placed JCheck boxes in the 3rd column of JTable by overriding its column class to return Boolean for the 3rd column.
So it appears as though we have check boxes in the 3rd column of the table...... lately I discovered that the table's list selection event gets fired only based on the "cell focus" in which the check box is present but not the check box itself.
i.e if the focus is on a particular cell (of 3rd column), the toggling of check box in the cell does not fire the event....
Am I missing some thing......
in which I placed JCheck boxes in the 3rd column of JTable by
overriding its column class to return Boolean for the 3rd column.
see Oracles JTable tutorial, to try code examples from tutorial
Boolean value represents JCheckBox in JTable
i.e if the focus is on a particular cell (of 3rd column), the toggling
of check box in the cell does not fire the event....
Am I missing some thing......
have to override public boolean isCellEditable(int row, int col)
Related
I have an Eclipse SWT table. It contains multiple rows (with row headers) and multiple columns (with column headers). On click on a column header I want to deselect all rows and highlight only the column's header (or all cells of this column). Is that possible?
I already registered a listener for the column header's selection and am able to set the selection to the given column, but then it also always selects the first row automatically. I tried with SWT.FULL_SELECTION and SWT.SINGLE as the style of my table, but it only changes the way how the row is highlighted, but I want only to highlight the column's header (or optionally all cells of this column) and no rows.
Is it possible? Did anyone have the same problem?
I ran into the same problem and I'm afraid you can't do that in SWT.
I solved by imitating the selection of a column; I colored the cells as if they were selected, and dropped the "real" selection.
You should extend your own TableViewer and override the getSelection() method to reflect that you now also have this imitated kind of selection.
(And from a UX perspective, you should make sure that a copy command (i.e. Ctrl+C) behaves as users expect it.)
I want to make a whole Row editable...e.g if user selected column 1 than click on edit button the table will show the whole row in editable form...it will be great if any one can give only code upon button event.
I want to make a whole Row editable...e.g if user selected column 1
than click on edit button the table will show the whole row in
editable form...it will be great if any one can give only code upon
button event.
I think have to use JToggleButton, because (JButtons) simple click is immediatelly finalized in comparing with JToggleButton (has two states)
for JTable have to set proper SelectionMode and to override public boolean isCellEditable(int row, int col) {
I have a custom JTable (15 rows by 20 cols) that was created to work for all JComponents. I'm currently using it for a mixture of JComboBoxes, JTextFields, and JButtons. Oh, and I'm using Java5 (a requirement).
I have two questions:
1) The first regards the TableCellRenderer class, and its single method:
public Component getTableCellRendererComponent(final JTable table,
final Object value,
final boolean isSelected,
final boolean hasFocus,
final int row,
final int column) {...}
All it does is cast the Object value argument to a JComponent, and potentially change the background color. No big deal. The question I have is why is this method is called sooooo often. When selecting a single cell, it is called 23 times. When Alt-Tabbing between two UNRELATED applications (I use Win7), this method is called over 200 times (and only for JButtons and JTextFields)!
Is this in any way necessary, and if not, how can I put a stop to unnecessary rendering calls?
2) The second question regards the JTable itself. When I'm editing a cell (cursor in a JTextField and blinking) and I click on another cell, that cell is only selected. If I then click on another cell, however, I start editing that cell. All I can think is that from the initial editing component, I'm selecting the JTable, and then selecting the component within. Is there any way to change this? Either going one way (always selects the jtable on first click) or the other (always enters cell on first click). I would prefer the first option, if possible.
Thansk to anyone who can grant some insight/help!
1) Why are you storing Components in the TableModel? That is not efficient. You should be storing data in the TableModel. JTable was designed to render data using a single component. The default renderer is generally a JLabel. Then when you edit a cell a different component is used.
When you click on a cell you may need to re-render the previous row (to remove the row selection) and then render the current row with the selection. So the renderer is called for each visible cell that is affected. Tabbing to the application probably causes all the visible cells to be re-rendererd.
2) Hard to answer since this is not the default behavour. You must also be using custom editors and I don't know what your custom code looks like. The default editor has a setClickCountToStart() method which defaults to 2. Maybe you set this to 1.
Change your solution to use data (not Components) in the TableModel and post your SSCCE if you have further questions.
There are a lot of discussions on web on how to have hyperlinks in swing and JTable, e.g. HyperLink in JTable Cell.
The approach above is problematic because it only knows which cell the mouse is in, not the exactly text it is on, which means:
Can not handle multiple hyperlinks in the same cell;
Can not make the mouse cursor showing intuitively. Whenever the mouse is in the cell that has hyperlink, the mouse will become hand shape, even when the mouse points to some normal text or even emtpy area.
Another approach is to display JEditorPane in the cell but is also problematic because JTable only uses the JComponent returned by cell renderer to draw, I don't think the object will be sent any events. Because the default renderer will re-use the component for every cell, so it doesn't make any sense to have it handle any events.
So I wonder what's the best way to achieve the above effect.
Another approach is to display JEditorPane in the cell but is also problematic because JTable only uses the JComponent returned by cell renderer to draw, I don't think the object will be sent any events.
Try placing the cell in edit mode every time the cell gains focus. Then the editor should be display which is a real component and it should reaceive all the events. Something like:
JTable table = new JTable(...)
{
// Place cell in edit mode when it 'gains focus'
public void changeSelection(int row, int column, boolean toggle, boolean extend)
{
super.changeSelection(row, column, toggle, extend);
if (editCellAt(row, column))
{
Component editor = getEditorComponent();
editor.requestFocusInWindow();
}
}
};
I would customize the code to only edit cell for the specific column.
I have created a JTable where the included items are provided with radio buttons in order to enable users to select any of these once at a time. In order to show always the first item selected when the JTable is initialised (or when the item previously selected has been deleted) what method should I use?
You should see the JTable Javadoc and particularly at :
getCellRect(int row, int column, boolean includeSpacing)
and
scrollRectToVisible(Rectangle aRect)
Something like
table.scrollRectToVisible(table.getCellRect(table.getSelectedRows()[0], 0, true));
should suit you.