Preamble
I have uneditable combobox (user can select from list, but can't type). I suppose, when user have focus on it and press DELETE, it's selection must be cleared? It seems that it is (screenshot was made when I selected some value and then pressed DELETE):
selectionModel is null - screenshot
Problem
But UI control still shows old value, it wasn't cleared. Also ValueChanged listener wasn't triggered.
How to cause
Create ComboBox and fill it with some values. Select any value. You already have selection on it, but it's not enough - now DELETE pressing won't even clear selectionModel. The same with selecting by TAB. Select it with double click (expand and collapse) and then press DELETE. Now selectionModel must be cleared, but UI still show your value.
Another thing: if you closed ComboBox, pressing DELETE will trigger ValueChanged listener. Pressing DELETE on expanded ComboBox won't trigger it, but nevertheless value will become null.
Did anybody face with this? Any ideas to make it work naturally i.e. clear selectionModel and update UI?
Well, the problem was not exactly where I thought. "Delete" button did nothing in any case, ComboBox was cleared because it's items list was refreshed every time when it was expanded -> old items were deleted including selected. Problem was the same - UI wasn't updated. So I resolved this by adding ComboBox.getEditor().clear() before refreshing it's items list in onShowing event.
Related
I start with the question and then describe the problem more in detail:
Question:
Is there a way to receive events from the listview of a JavaFx ComboBox directly (ComboBox consists of a listview and a textfield as far as I understand)? I would like to find out which element of the list has been clicked by mouse or which element was selected when the user pressed enter on the keyboard (after navigating with Up/Down Arrows in the list). I therefore need to receive the mouse click event or the keypress event on the listview, but all I can get so far are events on the combobox itself which turned out to be only changes in the textfield of the combobox.
Detailed problem description:
I have a JavaFx Application with a combobox where the idea is that the value is directly added to another list when the user clicks on an entry in the combobox list (when the popup of the combobox is open). Additionally, when the user navigates in the combobox list with the arrow keys on the keyboard and he presses enter, the currently selected value should be taken and added to the other list. However so far I have not found out how I can implement this feature with the standard JavaFx combobox.
Tried:
The first solution I tried was to add a change listener on the combobox's valueProperty (this is the value that is displayed in the textfield when the popup is closed). So when the user clicks on a listentry, the popup closes and the clicked entry is put into the value field, changes the value and therefore fires my change listener. This worked well with the mouse, but keyboard navigation did not work correctly because everytime the user navigates down or up on the list, the value field of the combobox is updated with the currently selected listentry and therefore fires my changelistener every time (which in turn adds the value to my other list, while it should only be added on enter keypress).
The next solution was to not add a listener to the valueProperty, but to the showingProperty. Everytime the combobox popup closes, the current value of the value field is taken and added to the other list. This works again well with the mouse, but still has issues with keyboard navigation. While it now correctly handles up/down navigation in the list and enter keypresses, the problem is now when you try to cancel the selection. When you press escape, the value is taken as well and added to the other list like you would have pressed enter. The problem with this approach is that I cannot find out with which keypress the popup has been closed.
So the next idea I had is to add an event filter to the combobox itself with the addEventFilter Method of the ComboBox with code similar to the following (also proposed here StackOverflow):
ComboBox comboBox = new ComboBox();
comboBox.addEventFilter(KeyEvent.KEY_PRESSED, (event) -> {
// do stuff
});
But the event filter never gets called when the combobox popup is open. It is only called when the popup is closed, which leads me to the assumption that the event is consumed by the listview. So the only solution to the problem seems to be to somehow capture the events from the listview itself. And that leads back to the question at the beginning of this post. Sorry for the long explanation.:-)
Came across this question while looking for something else. It touches on something I've worked on before so assuming I understand what you're trying to accomplish and also that this is still relevant here are a couple of ideas.
To keep the other list (list #2) in sync with the combo box for mouse clicks try:
A ChangeListener on the selectedItem property for the combo box's selectionModel. Clicking an item in the popup (drop-down) list view will change the selectedItem value and close the Window that 'owns' the list view, or
An event handler to the combo box for the event type ComboBoxBase.ON_HIDDEN which gets fired when the list view closes (or better said 'becomes hidden').
The ChangeListener may be problematic inasmuch as the selection models for the combo box and the list view are linked at a low level, so that changes to the selectedItem value for the list view which will be triggered when navigating with key strokes will necessarily be handled by the ChangeListener. Since you want to sync the combo box and list #2 only when the ENTER key is pressed, this will probably not work. But that still leaves the event handler idea to try.
As for ENTER key press, you need to get a handle for the list view itself, and then add whatever behavior (listeners/event handlers) as needed. You do this by getting the skin for the combo box, which should be an instance of ComboBoxListViewSkin, and then get the list view by invoking the getPopupContent() method for the skin; it returns the popup list view as a Node so you'll to recast the returned value but no big deal.
Hope this helps.
The idea of the below code is that ListView is created once the combobox is loaded in the JavaFX scene. Therefore, we add a listener on the combobox to check when it appears on the scene, and then through "lookup" method we get its listview and add a listener to it.
In the example, I have set a MouseEvent listener but you can easily adjust it for keys as well.
private EventHandler<MouseEvent> cboxMouseEventHandler;
private void initComboBox() {
ComboBox<String> comboBox = new ComboBox<String>();
comboBox.getItems().add("Item 1");
comboBox.getItems().add("Item 2");
comboBox.getItems().add("Item 3");
comboBox.sceneProperty().addListener((a,oldScene,newScene) -> {
if(newScene == null || cboxMouseEventHandler != null)
return;
ListView<?> listView = (ListView<?>) comboBox.lookup(".list-view");
if(listView != null) {
cboxMouseEventHandler = (e) -> {
Platform.runLater(()-> {
String selectedValue = (String) listView.getSelectionModel().getSelectedItem();
if(selectedValue.equals("Item 1"))
System.out.println("Item 1 clicked");
});
}; // cboxMouseEventHandler
listView.addEventFilter(MouseEvent.MOUSE_PRESSED, cboxMouseEventHandler);
} // if
});
} // initComboBox
I am facing a problem like I have one Vaadin ComboBox with preselected value.I am changing the value from the ComboBox to another value,then ValueChangeEvent is fired.Inside the valueChange method I have written something to show a Popup Window which has Cancel and Ok button.Upon clicking on OK button of Popup Window I am going with the changed value of the ComboBox but upon clicking on Cancel button I just want to have the old value which was there before value change event fired.
Could anyone please help me out from the above issue?
Thanks in advance.
Maybe you can save whatever SelectedItem the combobox has when the event is fired, and if the user pressed cancel, you reset it to this stored item.
Before the click, how do you know what is selected in the click? Of course, you need to store the current selection somewhere. Lets call it currentSelectedValue (it could be NULL in the begining)
On click, you have a new selection, lets call it newSelectedValue
Now, if you do not want to go with this newSelectedValue, simply do this:
combo.setValue(currentSelectedValue);
In my application, I have one tableview of items, and a side-panel "preview":ing the latest selected item.
I want clicking on an item to change the selection, and double-clicking to cause a "run"-action to be performed. More specifically, I want the "run"-action (including key-navigation and pressing enter) to be bound to the "activation" of the item in the table-row.
My problem is; single-clicks does not only change the selection, but fires the "activated" signal on the item. I would like to tweak it such that:
Navigation Keys, Single Mouse Click: Selection-change, update preview-panel
Enter Key, Double Mouse Click: Activate/run/open action triggered.
Is there a nice clean way to do it, or are overriding the onclick/doubleclick events my best option? Or is there some other tabular list-widget better suiting my needs?
I would connect the slot for the preview action to the currentChanged() signal of the table view's selectionModel(). This covers single clicks and key navigation.
Then there's two options for the double clicks and Enter key presses:
Subclass your tableview, override doubleClickEvent() and keyPressEvent() and fire your custom signal in there, with maybe the model index or something else as an argument. Then just connect your run method to your own signal as you have full control over when it is fired.
If you don't want to subclass, you can use the installEventFilter() mechanism.
Either I'm getting your approach wrong or I'm too tired, but if you want to trigger a run event you should avoid the activated signal completely. Set the signal slot mechanism so that your double click and Enter key press event trigger your run() function, and then the single click/nav buttons should trigger the 'activated' slot which will return your index in the tableview.
I'm pretty certain Qt wants you to be explicit about which signal points to which slot or it'll ignore it or point to a default.
Here's an image of what my problem is:
I am using a combo-box as a Datagrid ItemEditor (Not just Renderer, my Renderer is a Label, double clicking on a cell makes the combo-box visible, as is the case with all item editors)
Now, selecting one of the entries in the combo-box is no problem. But my problem is only when i select the "Fruit" , which in turn pops open another layer called "Select Fruit" dialog
Questions:
How do i keep item editor, while the focus is on the layer; right now as soon as i click on the fruit , my handler popsup the "Select Fruit" dialog and the focus is on the layer. Once the focus goes out of the editor, the ItemEditor goes away and ItemRenderer label comes back.
I want to keep the ItemEditor alive! where do I hook up interms of events like begin/end ItemEdit etc?
You can keep your itemEditor alive by listening for DataGridEvent.ITEM_EDIT_END. Then you have a lot more control to do what you want. Some FYI from my blog:
DataGridEvent.ITEM_EDIT_END
- Dispatched when focus is removed from the cell
- List-based control’s default event listener will
1) use the .editorDataFrield property to deterine the property of the item editor to store the edited data; In a default TextInput control’s item editor, the “text” property would contain the new data.
2) Invoke destoryItemEditor() depending on the reason of the event
You can interrupt the default List-based control’s default event listener by using event.preventDefault() to
a) Modify the data returned from the item editor
b) Examine/Validate the data entered into the item editor; If the data is incorrect, you can halt Flex passing the data back from the item editor into the list-based control
http://knowledge.lapasa.net/?p=153
Try losing focus of your ItemEditor. Goto Combo Box Change Listener
protected function comboBox_changeHandler(event:ListEvent):void
{
// set focus out event on datagrid. Its like clicking outside the datagrid
event.target.parent.parent.parent.dispatchEvent(new FocusEvent(FocusEvent.FOCUS_OUT);
}
I am facing a strange problem.
I have created a normal ext-gwt grid with two columns. One column displays a number and the other renders a ToggleButton. As soon as the ToggleButton gets pressed a small window appears with: 1- a textfield (to enter a number), 2- an ok button.
When the ok button is pressed the column containing the number should change it's value to the value given in the small window's textfield. This is the final picture I want to have. Easy! right?
The problem comes now. This is what is executed when the ok button is pressed in order to change the value in the column:
Integer value = new Integer(10);
Record record = store.getRecord(bean);
record.set("employeeNumber", value);
Although the value is actually changed using this code, it makes something weird. The ToggleButton remains in the "un-pressed" state whenever this code is executed. If I remove the last line, the ToggleButton functions normally again (gets pressed).
Any idea how to solve the problem of the ToggleButton?
Thank you
So you want the toggle button to change state after setting the value, right?
How do you get the toggle button into the grid?
I assume by using a custom widget renderer? In this case the render(..) method will be called more than once, returning a fresh and un-toggled button each time which will be displayed...
Maybe you could post some more code...?