Develop Reference

How to navigate through Vaadin grid and select an item using keyboard?

I'd like to know if it's possible to navigate through Vaadin grid or treegrid and select an item using only keyboard arrow keys? From what i've seen while testing the components, the default behavior seems to be either to move only to one specific cell in grid or to a specific row in treegrid. Selection can be achieved if the user presses spacebar.
I've tried to add a shortcutListener to grid but it doesn't seem to work with arrow keys. And the grid scrollbar doesn't move with the selected item.
grid.addShortcutListener(new ShortcutListener("Down", KeyCode.ARROW_DOWN, null) {
#Override
public void handleAction(Object sender, Object target) {
//..//
selectedItem = dataSource.get(currentSelectedItemIndex);
grid.select(selectedItem);
grid.scrollTo(currentSelectedItemIndex); // this doesn't seem to do anything??
//..//
}
});
I guess my problem is that i don't know how to acquire event that moves selection to other cell/row.
Here's an image to represent the problem which i'm facing. The item that has only blue border was selected using arrow keys. I'd like to select an item automatically when user presses arrow keys (Down or Up) without the spacebar.
Image taken from here: https://demo.vaadin.com/sampler/#ui/grids-and-trees/grid/features
Edit1:
I'm using latest version of Vaadin - 8.1.6.
Edit2:
I tried to add couple of listeners to see if i could at least register the movement to the next/previous cell by using arrow up/down but without any luck.
Here's a list of listeners i've tried:
addSelectionListener - only registers selection after spacebar press
or mouse click. Not quite what i'm looking for.
addItemClickListener - only registers selection from mouse click.
addShortcutListener - registers pressed key but it doesn't work with arrows.
Is there any listener that could potentially help me with this issue?

The Grid component has basic keyboard navigation. If you need advanced options, like you have mentioned, for keyboard navigation, I would warmly recommend to test this add-on:
https://vaadin.com/directory/component/gridfastnavigation-add-on

Is there a way to change the JComboBox's items focus?

I can change the item's focus by pressing the arrow keys on the keyboard or by moving the mouse over it. Is there a programmatic way to move the focus around the items?

You can simply set the selected item. Optionally, you can show the dropdown list:
comboBox.requestFocus();
comboBox.showPopup();
comboBox.setSelectedIndex(selectedIndex);

Java popup trigger in Linux

I have an application in which you can do a right mouse button press and drag (as well as a left press and drag for different operations). However, when running this on linux, it seems that popup menus are triggered by a mousePressed and not a mouseReleased. This is resulting in every time I press the right mouse button to perform a drag, the popup menus are triggered (unlike windows, where it is mouseReleased).
Any thoughts on how to work around this?
thanks.
EDIT: Posting code
Code for popup menu
// this is called from mousePressed and mouseReleased
if (e.isPopupTrigger() && !e.isConsumed()) {
// show the popup menu
}
This code is what is called on the right mouse press/drag (this is 3rd party code, but it is open source so I can change as needed)
// this is called on all mouse events
if (buttonAction.mouseButton != 0)
{
// handle the event
}

Yes, use isPopupTrigger(), as shown here.
Addendum:
it appears isPopupTrigger is triggered on mousePressed in linux.
Yes, it's the same on Mac OS X. You have to call isPopupTrigger() from both mousePressed() and mouseReleased(). There's a related example in GraphPanel.

MouseEvent.isPopupTrigger(). Returns whether or not this mouse event is the popup menu trigger event for the platform.
edit - : You need to make the check in both mousePressed for linux, and mouseReleased for windows.

I think the correct procedure in your case should be to unify where and when to show the popup. As a drag event, if exist, follows a press event you should avoid writting logic for showing the popup in the press event (and then also write logic in the press event for showing the popup). Some users feel good navigating the popup while holding the popup button, and some other users just don't care or don't know. But in your case, you won't be able to navigate the popup menu while dragging without adding extra code.
My way would we to manage the logic to always show the popup on the release event. Entering a release event after a drag should be enough information to know that the popup shouldn't be visible. And of course, always if you can change and modify the source.

generic listeners for swt radio buttons

I'm developing a SWT app and in one particular form there are 14 pairs of Yes-No radio buttons. Each of these pairs have a text box associated with them. So if a user selects Yes, the associated textbox should be editable else uneditable. I find writing 28 listeners for the radio buttons really daunting. Since the radio buttons have nothing much to do than just rendering the textbox editable/uneditable I was hoping if there were some generic type of listeners in SWT that would be applicable to a set of radio buttons specified in an array or like that. Are there any frameworks or shall I have to write individual listeners?
Edit
I'm trying to fire an event only when the radio button is selected
rdoExperience.addListener(SWT.CHECK, new RadioButtonSelection(
txtExperience));
but SWT.CHECK is causing the event to be fired on mouse hover over radio button too. I've tried using SWT.SELECTED too but it's not working either and I can't find other suitable SWT constants. W;hat should I use?

Good point. Sorry I don't know such thing.
However, you create one yourself: Instead of writing an anonymous listener for every button, you could write one - say MyButtonListener - and give it the button text box as an argument. Than you instantiate MyButtonListener with the appropriate text box as an argument. Than in the Listeners appropriate callback method you enable or disable the text box.
Edit: My bad. Of course I meant you could give it your text box like radioBtn.addListener(SWT.SELECTED, new MyButtonListener(textfield1));

You could create one SelectionListener and add it to each of the radio buttons. Then you can ascertain which button was pressed from the selection event and map that to a text box. For the mapping you could use an array or hashtable.

JTable cell loses focus after run an action on selected cells if use keyboard shortcut and temporaily disable the JTable

In my JTable I have a number of actions that can accessed via popup menu or by selecting the configured shortcut. Selecting the action from the popup using mouse or keyboard is fine, and I can use the cursor keys to move to a field next to the original selection no problem. However if I use the shortcutkey instead it performs the action okay but I cannnot exit the selected fields afterwards using the cursor keys, because for some reason the focus is now with a component outside of the JTable.
EDIT:When I start the task I change the cursor and disable the JTable, when I complete the task I renable the table and reset the cursor. If I remove the disable code it works, but this then allow the user to make changes to the table which I dont want, and I cannot understand why it only fails when using keyboard shortcut.

Fixed the problem, after renabling the Jtable I needed to call requestFocusInWindow()