for my app I need the space key to call a function independent from the focused widget, everywhere in the app but only if the according tab is opend. I found that one can add a filter to the display, like this:
getShell().getDisplay().addFilter(SWT.KeyDown, new Listener() {
public void handleEvent(Event arg0) {
if( arg0.character == 32 ) { /**SPACE*/
if( mainTabs.getSelection().equals(analyseSoundFilesTab)) {
soundController.playButtonClickHandler();
}
}
}
});
That works fine most of the time, but if I give a button the focus via the "tab" or "shift tab", its kinda strange - the space bar will than activate a "button pressed", as if one clicks the button with the mouse. Im a bit stuck now, I don't know how to avoid this...
For the buttons, I have implemented a SelectionListener.
Regards.
You can use TraverseListener and disabled press event detection using doin field. Here is a sample code:
display.addFilter(SWT.KeyDown, new Listener() {
public void handleEvent(Event e) {
if (e.character == 32) {
System.out.printf("Space detected %s\n", e);
}
}
});
Button b1 = new Button(shell, SWT.PUSH);
b1.addSelectionListener(new SelectionAdapter() {
#Override
public void widgetSelected(SelectionEvent se) {
System.out.printf("Button pressed %s\n", se);
}
});
b1.addTraverseListener(new TraverseListener() {
#Override
public void keyTraversed(TraverseEvent te) {
System.out.printf("Traverse detected %s\n", te);
te.doit = true;
}
});
If addTraverseListener() didn't exist, your space button was detected after filter, so you would see "Space detected..." and after that "Button pressed...". Now that you set te.doit = true, you say to SWT to do space bar traversal (which does nothing actually) instead of firing key listener. You may optionally check te.detail to only prevent mnemonic traversals.
Choosing the 'Space key' is the real problem, because it is a general feature in most (all?) OS's that pressing space is equal to selecting the widget that has focus.
A way out would be using subclassed Button widgets that ignoring Space.
But it would confuse a lot of users, just because they expect that a focussed button is selected when they hit space and do not expect some other action.
Related
I was checking for an event that indicates if the Combo display list is open, but did not see anything.
I thought of a mouse down/up event hook, but I quickly realized that a user presses and releases the mouse to display the list. Also, one can use a keyboard.
I saw this article, which said to use the getListVisible() method, however that would either some sort of timer. A mouse up event is not quite accurate for implementing the check and a timer seems like major overkill for a simple task.
cboServers = new Combo(this.cmptLogHtsControl, SWT.BORDER | SWT.MULTI | SWT.V_SCROLL);
cboServers.addMouseListener(new MouseAdapter()
{
#Override
public void mouseDown(MouseEvent arg0)
{
}
#Override
public void mouseUp(MouseEvent arg0)
{
}
});
gridData = new GridData(GridData.FILL, GridData.FILL, true, true);
gridData.widthHint = 300;
cboServers.setLayoutData(gridData);
this.cboServers.addSelectionListener(new SelectionAdapter()
{
#Override
public void widgetSelected(SelectionEvent arg0)
{
}
});
Am I missing something? Thoughts?
Since the popup is done by the native control there probably isn't any way to see this.
Looking at the implementation of Combo on Mac OS X getListVisible() is done using events which are specific to OS X and are not exposed in the SWT API.
I've designed (using the GUI designer within Netbeans) a small dialog with two radio buttons and a number spinner.
If I press Enter while the focus is on one of the radio buttons, the dialog correctly closes, but if the focus is on the spinner, I have to Tab away from it in order to use the Enter key.
How do I instruct the dialog that Enter really means "accept and close"?
Alternatively, how do I instruct (each) input field to relay an Enter to the "accept and close" handler?
Similarly, how do I instruct the dialog that Esc really means "cancel and close" even when the focus is on the spinner (or other field)?
how do I instruct (each) input field to relay an Enter to the "accept and close" handler?
The easiest approach is to define a "default button" on the dialog. Then when Enter is pressed the default button will be activated. Check out Enter Key and Button for different ways to do this.
how do I instruct the dialog that Esc really means "cancel and close"
Use Key Bindings to invoke the Action of your Cancel button.
First you define an Action to be used by the button:
public class CancelAction extends AbstractAction
{
public CancelAction()
{
super("Cancel");
putValue( Action.MNEMONIC_KEY, new Integer(KeyEvent.VK_C) );
}
#Override
public void actionPerformed(ActionEvent e)
{
Window window = KeyboardFocusManager.getCurrentKeyboardFocusManager().getActiveWindow();
if (window != null)
{
WindowEvent windowClosing = new WindowEvent(window, WindowEvent.WINDOW_CLOSING);
window.dispatchEvent(windowClosing);
}
}
}
Then you add the Action to the button so the user can use the mouse:
CancelAction cancelAction = new CancelAction();
cancelButton.setAction( cancelAction );
dialog.add(cancelButton);
Now you can use Key Bindings to bind the Escape key to the CancelAction so the user can use the keyboard:
KeyStroke escapeKeyStroke = KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE, 0, false);
getRootPane().getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(escapeKeyStroke, "ESCAPE");
getRootPane().getActionMap().put("ESCAPE", cancelAction);
I suspect the reason I had problems is that a spinner is really a compound control, and the text (well, number) field is an component of that. So I needed to hook up the events to that subcomponent, rather than to the spinner itself:
// Make Ok/Cancel work when JSpinner has focus
getSpinnerField(jSpinnerOffset).addActionListener(new java.awt.event.ActionListener() {
#Override
public void actionPerformed(java.awt.event.ActionEvent evt) {
doOk();
}
});
where "getSpinnerField()" is just a shorthand in a private method:
private JFormattedTextField getSpinnerField(JSpinner spinner) {
return ((JSpinner.DefaultEditor) spinner.getEditor()).getTextField();
}
Doing this, the Esc key automagically becomes able to dismiss the dialog.
Simplified code
play = new PushButton("Play");
play.getUpFace().setImage(new Image(pathToImages+offImage));
play.getUpHoveringFace().setImage(new Image(pathToImages+hoverImage));
play.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
//This event is captured
}
});
I require a keyboard button as a shortcut to play button accordingly I have added
Event.addNativePreviewHandler(new NativePreviewHandler() {
#Override
public void onPreviewNativeEvent(NativePreviewEvent event)
{ //Call the functionality of play button for the approriate key press
}
});
But once I click the play button using mouse the above nativePreviewHandler does not capture the key press event from keyboard.
So I added a keyDownHandler to the play button
play.addKeyDownHandler(new KeyDownHandler() {
#Override
public void onKeyDown(KeyDownEvent event) {
//This event is never fired
}
});
But the above onKeyDown() method is never called.
Only after I click at some other place on screen is the key press event captured by the nativePreviewHandler.
Just as additional info, I tried following without success
Added DomHandler to the play button instead of keyDownHandler
Removed the images set to the play button
Tried to unfocus the play button every time it is pressed using play.setFocus(false);
Any possible solutions or suggestions are appreciated.
The play button need to have the focus in order to be able to catch the keyDownEvent.
Could you check this ?
If you can't set the focus on that button: check this answer. You need to set a keyDownHandler to a container and ensure it is focused at all time in order to catch the events even if your button is not focused.
This will work:
Event.addNativePreviewHandler(new NativePreviewHandler() {
#Override
public void onPreviewNativeEvent(NativePreviewEvent event) {
if (event.getNativeEvent().getType().equals("keydown")) {
Window.alert("Code: " + Integer.toString(event.getNativeEvent().getKeyCode()));
}
}
});
i have a Jframe application with the defaultbutton set to btnClose_ (Close Button: this button closes the window).
I have 2 textfields that must also fire an event when user clicks the Enter key on the textfields. What happens is that when I press the Enter key while the cursor is on the textfield, the event on the Close button is fired causing the window to close.
Is it possible to remove the listener of the default button if the Enter key is pressed on the textfield? Here's my code for the textfield listener
/**
* Receives the two textfield instance
*/
private void addFilterListener(JTextField txf) {
txf.addKeyListener(new KeyAdapter() {
/**
* Invoked when a key has been pressed.
*/
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_ENTER) {
ActionListener al = btnClose_.getActionListeners()[0];
btnClose_.removeActionListener(al);
btnFilter_.doClick();
e.consume();
btnClose_.addActionListener(al);
}
}
});
}
private JButton getBtnClose(){
if(btnClose == null){
btnClose.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
getWindow().dispose();
}
});
}
return btnClose;
}
}
Where to start?
The first thing that springs out at me is the bad variable names. txf? What's wrong with proper words? textField or field, say. Or much better, a name descriptive of its purpose, not what it is.
Secondly, the first comment is wrong (not uncommon) and the second comment is redundant (already specified in the KeyListener interface, you don't need to try and half-heartedly specify it again).
Next up, low level key listeners tend not to work so well on Swing components (JComboBox being the most notorious example - it typically is implemented with child components). In general you can use JComponent.registerKeyboardAction (the API docs says this is obsolete but not deprecated, and to use more verbose code). For text components, you often want to play with the document (typically through DocumentFilter). In this particular case, looks like you just want to add an ActionListener.
Now doClick. It's a bit of an evil method. For one thing it blocks the EDT. It is probably the easiest way to make it look as if a button is pressed. From a programming logic point of view, it's best to keep away from modifying Swing components, when you can keep everything in your abstracted code.
Removing and adding listeners from components is generally a bad idea. Your code should determine what to do with an event including whether to ignore it. Do that at an appropriate point when handling the event. Don't duplicate state unnecessarily.
A potential issue is that the code seems to assume that there is precisely one action listener. There could be others. The code is not robust under unexpected behaviour. Set your components up at initialisation time, and you shouldn't need to refer to them again.
As far as I understood your question, you want that buttonClick should not get fired if Enter is pressed .
This won't fire doClick() if enter is pressed
if (e.getKeyCode() != KeyEvent.VK_ENTER) {
btnFilter_.doClick();
}
In the ActionListener of the close button, assuming you can change its code, don't close if one of the text fields have the focus.
public void actionPerformed(ActionEvent e) {
if (field1.hasFocus() || field2.hasFocus())
return; // don't close if text field has focus
frame.dispose();
}
If you can not change the ActionListener of the close button, add a FocusListener to the text fields. If one of them gets the focus, remove the default button. If the text field lost the focus, reset the default button.
FocusAdapter listener = new FocusAdapter() {
#Override
public void focusGained(FocusEvent e) {
frame.getRootPane().setDefaultButton(null);
}
#Override
public void focusLost(FocusEvent e) {
frame.getRootPane().setDefaultButton(close);
}
};
field1.addFocusListener(listener);
field2.addFocusListener(listener);
This should be better than depending on the listeners being called in the correct sequence - it is of no avail to remove the listener if it was already called...
Using standalone SWT Scrollbars is something of a hack (using this workaround), but it can be done. Here's a snippet:
ScrolledComposite scrolledComposite = new ScrolledComposite(
parent, SWT.V_SCROLL);
ScrollBar scrollbar = scrolledComposite.getVerticalBar();
Shell tip = new Shell(UserInterface.getShell(), SWT.ON_TOP
| SWT.NO_FOCUS | SWT.TOOL);
// ..stylize and fill the tooltip..
Now what I'm trying to do is monitor when the user is interacting with the scrollbar. In particular, I want to know when the user is dragging the scrollbar—and when it has been released—in order to display an Office 2007-style tooltip revealing which page the position of the scrollbar corresponds with.
Presently, I have the following code which displays the tooltip:
scrollbar.addSelectionListener(new SelectionListener() {
public void widgetDefaultSelected(SelectionEvent event) {}
public void widgetSelected(SelectionEvent event) {
tip.setVisible(true);
}
}
It would seem logical then to have the tooltip disappear when the mouse button is released:
scrollbar.addListener(SWT.MouseUp, new Listener() {
public void handleEvent(Event event) {
tip.setVisible(false);
}
});
However, neither scrollbar nor scrolledComposite seem to respond to the SWT.MouseUp event when the user interacts with the scrollbar.
I presently have a workaround that hides the tip after a timeout, but I'm not satisfied with this. Any insights would be most appreciated!
Scrollbar's javadoc said this:
When widgetSelected is called, the
event object detail field contains one
of the following values: SWT.NONE -
for the end of a drag. SWT.DRAG.
SWT.HOME. SWT.END. SWT.ARROW_DOWN.
SWT.ARROW_UP. SWT.PAGE_DOWN.
SWT.PAGE_UP. widgetDefaultSelected is
not called.
So my suggestion is get your tooltip to appear and disappear is to check for the event.detail type.
public void widgetSelected(SelectionEvent event) {
tip.setVisible(event.detail != SWT.NONE);
}
scrollBar.addSelectionListener(new SelectionListener() {
public void widgetDefaultSelected(SelectionEvent e) {
}
public void widgetSelected(SelectionEvent e) {
if (e.detail == SWT.NONE) {
// end of drag
System.out.println("Drag end");
}
else if (e.detail == SWT.DRAG) {
// drag
System.out.println("Currently dragging");
}
}
});
Hope this will help you... But I can see a problem with mousewheel use that throws multiple drag end events...
Paul,
try using addMouseEvent method from a Scrollable object. For example:
Scrollable scrollable = scrollbar.getParent();
scrollable.addMouseListener(new MouseListener () {
void mouseDoubleClick(MouseEvent e) { ... }
void mouseDown(MouseEvent e) { ... }
void mouseUp(MouseEvent e) { ... }
});
Actually, I don't know if this approach will work. But, it's an attempt.
Good luck!