Develop Reference

SWT Adding KeyListener to a Display

I want to add a KeyListener to my existing window. I want to catch 3 KeyDown's. On the first KeyDown I want to put something in a Combo. On the second KeyDown I want to put something in another Combo. If both textbox are filled, I want the next KeyDown to simulate the OK Button.
But I have a problem with the error widget disposed. Because I dont know when to remove the filter correct. This only happend if I open the window again!
My Code:
_disp.addFilter(SWT.KeyDown, new Listener() {
public void handleEvent(Event e) {
if(!_disp.isDisposed()){
_disp.removeFilter(SWT.KeyDown, this);
}
if (e.keyCode == SWT.CR) {
if (_cmbCCID.getText().isEmpty()) {
_cmbCCID.setText(_lastFiveCCID[0]);
} else if (_cmbDescription.getText().isEmpty()) {
_cmbDescription.setText(_lastFiveComment[0]);
} else if (!_cmbCCID.getText().isEmpty() && !_cmbDescription.getText().isEmpty()) {
_btnOk.notifyListeners(SWT.Selection, new Event());
}
}
}
});

You're removing the filter after the first key press. Try something like this:
public static void main(String[] args)
{
final Display display = new Display();
Shell shell = new Shell(display);
shell.setText("StackOverflow");
shell.setLayout(new FillLayout());
new Text(shell, SWT.NONE);
display.addFilter(SWT.KeyDown, new Listener()
{
int i = 0;
#Override
public void handleEvent(Event arg0)
{
if (i < 2)
System.out.println("Press " + i);
else
{
System.out.println("Press " + i);
System.out.println("Remove");
if (!display.isDisposed())
display.removeFilter(SWT.KeyDown, this);
}
i++;
}
});
shell.pack();
shell.open();
while (!shell.isDisposed())
{
while (!display.readAndDispatch())
{
display.sleep();
}
}
}
It will remove the filter after the third key press event.

Hide ON_TOP shell in SWT on Display minimimized

I'm trying to hide a SWT shell when the Display is minimized. I'm missing something and would be most thankful for any help.
Additional Info: This shell is actually a popup that gets drawn when the user clicks on a composite. In the end, my goal is to hide this popup-shell when the composite is not visible (user minimized the window or switched between windows, say with Alt+Tab for example).
Here's my code:
static Shell middleClickNodeInfoShell ;
static Label nodeIdLabel ;
void init(){
...
/** Focused node on middle click*/
middleClickNodeInfoShell = new Shell(Display.getDefault(), SWT.BORDER | SWT.MODELESS);
middleClickNodeInfoShell.setLayoutData(new GridData(GridData.FILL, GridData.BEGINNING, true, false));
middleClickNodeInfoShell.setLayout(createNoMarginLayout(1, false));
nodeIdLabel = new Label(middleClickNodeInfoShell, SWT.NONE);
Display.getDefault().addListener(SWT.Iconify,new Listener() {
#Override
public void handleEvent(Event arg0) {
// TODO Auto-generated method stub
middleClickNodeInfoShell.setVisible(false);
}
});
}
#Override
public boolean onMouseClicked(Button button, ScreenPosition screenPos,
final GeoPosition arg2) {
...
nodeIdLabel.setText("Node Id: "+node.getId());
middleClickNodeInfoShell.setLocation(pos.getX()+displayX,pos.getY()+displayY+30);
middleClickNodeInfoShell.setVisible(true);
middleClickNodeInfoShell.pack();
}

Here is sample code that will help you do figure out what you are looking for
public static void main(String[] args) {
final Display display = new Display();
final Shell shell = new Shell(display);
shell.setSize(300, 200);
shell.setText("Shell Example");
shell.setLayout(new RowLayout());
final Button button = new Button(shell, SWT.PUSH);
button.setText("Click Me");
final Shell tip = new Shell(shell,SWT.MODELESS);
tip.setLayout(new FillLayout());
Label lbl = new Label(tip, SWT.NONE);
lbl.setText("***tooltip***");
tip.pack();
shell.addControlListener(new ControlListener() {
#Override
public void controlResized(ControlEvent e) {
changeTipLocation(display, button, tip);
}
#Override
public void controlMoved(ControlEvent e) {
changeTipLocation(display, button, tip);
}
});
button.addSelectionListener(new SelectionAdapter() {
public void widgetSelected(SelectionEvent event) {
changeTipLocation(display, button, tip);
tip.open();
}
});
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
private static void changeTipLocation(final Display display, final Button button, final Shell tip) {
Rectangle bounds = button.getBounds();
Point loc = button.getLocation();
tip.setLocation(display.map(button, null, new Point(loc.x+bounds.width, loc.y+bounds.height)));
}

SWT: Differentiating between selection and typing in a combo

Consider the following Java (SWT) code:
private static ComboViewer createViewer(final Shell shell) {
final ComboViewer v = new ComboViewer(shell, SWT.DROP_DOWN);
v.setLabelProvider(new LabelProvider());
v.setContentProvider(new ArrayContentProvider());
v.setInput(new String[]{"value 1", "value 2"});
return v;
}
public static void main(final String[] args) {
Display display = new Display();
Shell shell = new Shell(display);
shell.setSize(200, 60);
shell.setLayout(new GridLayout());
final ComboViewer v = createViewer(shell);
// This wires up the userSelectedSomething method correctly
v.addSelectionChangedListener(new ISelectionChangedListener() {
#Override
public void selectionChanged(final SelectionChangedEvent event) {
userSelectedSomething();
}
});
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}
public static void userSelectedSomething() {
// This should be called *only if* the user selected from the drop-down
}
public static void userTypedSomething() {
// This should be called *only if* the user typed in the combo
}
I want to call the userTypedSomething method only if the user typed into the combo (and not when they selected from the drop-down). What listener should I add to achieve this? Adding a modify listener to the combo viewer with v.getCombo().addModifyListener(...) is no good as this is triggered for both typing and selection from the combo.

private static ComboViewer createViewer(final Shell shell) {
final ComboViewer v = new ComboViewer(shell, SWT.DROP_DOWN);
v.setLabelProvider(new LabelProvider());
v.setContentProvider(new ArrayContentProvider());
v.setInput(new String[]{"value 1", "value 2"});
return v;
}
private static boolean userTyped;
private static int index = -1;
public static void main(final String[] args) {
Display display = new Display();
Shell shell = new Shell(display);
shell.setSize(200, 60);
shell.setLayout(new GridLayout());
final ComboViewer v = createViewer(shell);
/*
* invoked multiple times when combo selection happens
* invoked once when user types
*/
v.getCombo().addVerifyListener(new VerifyListener() {
#Override
public void verifyText(VerifyEvent e) {
userTyped = (e.keyCode != 0);
}
});
v.getCombo().addModifyListener(new ModifyListener() {
#Override
public void modifyText(ModifyEvent e) {
Combo c = (Combo)e.widget;
if(userTyped || index == c.getSelectionIndex() || c.getSelectionIndex() == -1)
{
userTypedOrEditedSomething();
}
index = c.getSelectionIndex();
}
});
// This wires up the userSelectedSomething method correctly
v.addSelectionChangedListener(new ISelectionChangedListener() {
#Override
public void selectionChanged(final SelectionChangedEvent event) {
userSelectedSomething();
}
});
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}
public static void userSelectedSomething() {
// This should be called *only if* the user selected from the drop-down
System.out.println("User selected");
}
public static void userTypedOrEditedSomething() {
// This should be called *only if* the user typed in the combo
System.out.println("User typed or edited");
}
I would suggest you to use Verify event instead Key UP as you might endup handling lot of things (arrow keys, magic keys...etc). Verify is also Key Event but it filter out ALT,CNTRL,SHIFT combination. When user types just check for keycode!=0.
As you pointed out, when you use CNTRL+V ,Right click Menu paste....combo doesn't consider it as key event but it fires verify event to make sure the clipboard text is valid for combo or not. I think this is how it should work as Menu item selection and Key event on combo are different things.
you can always monitor all key events for special actions like copy/paste/delete.
the above sample code should be able to perform what you are looking for.

Since you want to listen to keyboard input, I would suggest listening to SWT.KeyUp.
This should be a good starting point:
public static void main(String[] args) {
final Display display = new Display();
final Shell shell = new Shell(display);
shell.setLayout(new FillLayout());
final Combo combo = new Combo(shell, SWT.NONE);
combo.add("First");
combo.add("Second");
combo.addListener(SWT.Selection, new Listener() {
#Override
public void handleEvent(Event arg0) {
System.out.println("Selected: " + combo.getItem(combo.getSelectionIndex()));
}
});
combo.addListener(SWT.KeyUp, new Listener() {
#Override
public void handleEvent(Event arg0) {
System.out.println("Typed");
}
});
shell.pack();
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}

How do I make it possible to resize a composite by dragging the corner

I am working with SWT and I would like to be able to resize a composite by dragging the corner of it, the same way that you can resize a shell. I'm sure someone out there has implemented a good solution. Thanks.

I think what you are looking for can be implemented with org.eclipse.swt.widgets.Tracker
here is sample working code:
public static void main(String[] args) {
Display display = new Display();
final Shell shell = new Shell(display);
shell.open();
final Composite b = new Composite(shell, SWT.NONE);
b.setBounds(20, 20, 80, 80);
b.setBackground(display.getSystemColor(SWT.COLOR_BLUE));
b.addListener(SWT.MouseDown, new Listener() {
public void handleEvent(Event e) {
Tracker tracker = new Tracker(b.getParent(), SWT.RESIZE);
tracker.setStippled(true);
Rectangle rect = b.getBounds();
tracker.setRectangles(new Rectangle[] { rect });
if (tracker.open()) {
Rectangle after = tracker.getRectangles()[0];
b.setBounds(after);
}
tracker.dispose();
}
});
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}

How to show up an image with swt in java?

My try as follows,which doesn't come up with anything:
public static void main(String[] args) {
Display display = new Display();
Shell shell = new Shell(display);
Image image = new Image(display,
"D:/topic.png");
GC gc = new GC(image);
gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
gc.drawText("I've been drawn on",0,0,true);
gc.dispose();
shell.pack();
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
// TODO Auto-generated method stub
}

See the SWT-Snippets for examples. This one uses an image label
Shell shell = new Shell (display);
Label label = new Label (shell, SWT.BORDER);
label.setImage (image);

You are missing one thing in your code. Event Handler for paint. Normally when you create a component it generates a paint event. All the drawing related stuff should go in it.
Also you need not to create the GC explicitly.. It comes with the event object :)
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;
public class ImageX
{
public static void main (String [] args)
{
Display display = new Display ();
Shell shell = new Shell (display, SWT.SHELL_TRIM | SWT.DOUBLE_BUFFERED);
shell.setLayout(new FillLayout ());
final Image image = new Image(display, "C:\\temp\\flyimage1.png");
shell.addListener (SWT.Paint, new Listener ()
{
public void handleEvent (Event e) {
GC gc = e.gc;
int x = 10, y = 10;
gc.drawImage (image, x, y);
gc.dispose();
}
});
shell.setSize (600, 400);
shell.open ();
while (!shell.isDisposed ()) {
if (!display.readAndDispatch ())
display.sleep ();
}
if(image != null && !image.isDisposed())
image.dispose();
display.dispose ();
}
}