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Scroll horizontally when dragging/reordering columns in the TableView

In JavaFX's TableView (and TreeTableView) it's really hard to reorder columns using drag & drop when the horizontal scrollbar is present, because the table doesn't scroll automatically when one want's to drag the column to the currently not visible (off the scroll pane viewport) position.
I've noticed that there are already a bug (enhancement) reports for this:
https://bugs.openjdk.java.net/browse/JDK-8092314
https://bugs.openjdk.java.net/browse/JDK-8092355
https://bugs.openjdk.java.net/browse/JDK-8213739
... but as it haven't been tackled for quite some time I am wondering whether there is any other way to achieve the same behavior using the current API.
There is SSCCE:
public class TableViewColumnReorderDragSSCCE extends Application {
public static final int NUMBER_OF_COLUMNS = 30;
public static final int MAX_WINDOW_WIDTH = 480;
#Override
public void start(Stage stage) {
stage.setScene(new Scene(createTable()));
stage.show();
stage.setMaxWidth(MAX_WINDOW_WIDTH);
}
private TableView<List<String>> createTable() {
final TableView<List<String>> tableView = new TableView<>();
initColumns(tableView);
return tableView;
}
private void initColumns(TableView<List<String>> tableView) {
for (int i=0; i<NUMBER_OF_COLUMNS; i++) {
tableView.getColumns().add(new TableColumn<>("Column " + i));
}
tableView.getItems().add(Collections.emptyList());
}
}
Steps to reproduce:
Run the above SSCCE
Try to drag Column 0 after Column 29
I am after a fully functional solution (if any).

As no complete solution was provided I've came up with one of my own. I've introduced a (ColumnsOrderingEnhancer) implementation which will enhance the table view columns reordering by automatic scrolling (when needed).
Usage (with the table view defined in the above SSCCE):
// Enhance table view columns reordering
final ColumnsOrderingEnhancer<List<String>> columnsOrderingEnhancer = new ColumnsOrderingEnhancer<>(tableView);
columnsOrderingEnhancer.init();
ColumnsOrderingEnhancer implementation:
public class ColumnsOrderingEnhancer<T> {
private final TableView<T> tableView;
public ColumnsOrderingEnhancer(TableView<T> tableView) {
this.tableView = tableView;
}
public void init() {
tableView.skinProperty().addListener((observable, oldSkin, newSkin) -> {
// This can be done only when skin is ready
final TableHeaderRow header = (TableHeaderRow) tableView.lookup("TableHeaderRow");
final MouseDraggingDirectionHelper mouseDraggingDirectionHelper = new MouseDraggingDirectionHelper(header);
final ScrollBar horizontalScrollBar = getTableViewHorizontalScrollbar();
// This is the most important part which is responsible for scrolling table during the column dragging out of the viewport.
header.addEventFilter(MouseEvent.MOUSE_DRAGGED, event -> {
final double totalHeaderWidth = header.getWidth();
final double xMousePosition = event.getX();
final MouseDraggingDirectionHelper.Direction direction = mouseDraggingDirectionHelper.getLastDirection();
maybeChangeScrollBarPosition(horizontalScrollBar, totalHeaderWidth, xMousePosition, direction);
});
});
}
private void maybeChangeScrollBarPosition(ScrollBar horizontalScrollBar, double totalHeaderWidth, double xMousePosition, MouseDraggingDirectionHelper.Direction direction) {
if (xMousePosition > totalHeaderWidth && direction == RIGHT) {
horizontalScrollBar.increment();
}
else if (xMousePosition < 0 && direction == LEFT) {
horizontalScrollBar.decrement();
}
}
private ScrollBar getTableViewHorizontalScrollbar() {
Set<Node> scrollBars = tableView.lookupAll(".scroll-bar");
final Optional<Node> horizontalScrollBar =
scrollBars.stream().filter(node -> ((ScrollBar) node).getOrientation().equals(Orientation.HORIZONTAL)).findAny();
try {
return (ScrollBar) horizontalScrollBar.get();
}
catch (NoSuchElementException e) {
return null;
}
}
/**
* A simple class responsible for determining horizontal direction of the mouse during dragging phase.
*/
static class MouseDraggingDirectionHelper {
private double xLastMousePosition = -1;
private Direction direction = null;
MouseDraggingDirectionHelper(Node node) {
// Event filters that are determining when scrollbar needs to be incremented/decremented
node.addEventFilter(MouseEvent.MOUSE_PRESSED, event -> xLastMousePosition = event.getX());
node.addEventFilter(MouseEvent.MOUSE_DRAGGED, event -> {
direction = ((event.getX() - xLastMousePosition > 0) ? RIGHT : LEFT);
xLastMousePosition = event.getX();
});
}
enum Direction {
LEFT,
RIGHT
}
public Direction getLastDirection() {
return direction;
}
}
}
End result (which works surprisingly well):

It's not impossible to work around. You could start with something like this, though it is a very crude implementation, I'm sure in principle it can be refined to something reasonable:
tableView.setOnMouseExited(me -> {
if (me.isPrimaryButtonDown()) { // must be dragging
Bounds tvBounds = tableView.getBoundsInLocal();
double x = me.getX();
if (x < tvBounds.getMinX()) {
// Scroll to the left
tableView.scrollToColumnIndex(0);
} else if (x > tvBounds.getMaxX()) {
// Scroll to the right
tableView.scrollToColumnIndex(tableView.getColumns().size()-1);
}
}
});
In a proper implementation you would likely have to sneak around the Node hierarchy and find the width of the table columns and determine what the next out-of-view column is so you can scroll to the exact right column. Remember when you did that so you can do it again if the user continues to drag outside the table, but not too fast.
EDIT: Based on your self-answer, here is my take on it. I've compacted your code a bit and made it work on JavaFX 8.0:
static class TableHeaderScroller implements EventHandler<MouseEvent> {
private TableView tv;
private Pane header;
private ScrollBar scrollBar;
private double lastX;
public static void install(TableView tv) {
TableHeaderScroller ths = new TableHeaderScroller(tv);
tv.skinProperty().addListener(ths::skinListener);
}
private TableHeaderScroller(TableView tv) {
this.tv = tv;
}
private void skinListener(ObservableValue<? extends Skin<?>> observable, Skin<?> oldValue, Skin<?> newValue) {
if (header != null) {
header.removeEventFilter(MouseEvent.MOUSE_DRAGGED, this);
}
header = (Pane) tv.lookup("TableHeaderRow");
if (header != null) {
tv.lookupAll(".scroll-bar").stream().map(ScrollBar.class::cast)
.filter(sb -> sb.getOrientation() == Orientation.HORIZONTAL)
.findFirst().ifPresent( sb -> {
TableHeaderScroller.this.scrollBar = sb;
header.addEventFilter(MouseEvent.MOUSE_DRAGGED, TableHeaderScroller.this);
});
}
}
#Override
public void handle(MouseEvent event) {
double x = event.getX();
double sign = Math.signum(x - lastX);
lastX = x;
int dir = x < 0 ? -1 : x > header.getWidth() ? 1 : 0;
if (dir != 0 && dir == sign) {
if (dir < 0) {
scrollBar.decrement();
} else {
scrollBar.increment();
}
}
}
}

Spring boot app with Vaadin UI constantly refreshing screen

I have a boot app that I am adding some crud screens to. I decided to use Vaadin and it seems to work great until I deploy it to a multi-nodal production environment.
Once in the prod environment the screens constantly refresh for no apparent reason. For example there is a grid in one screen that when a row is clicked a dialog pops up that shows item details. but as soon as the dialog pops up the page refreshes numerous times.
This forum thread here https://vaadin.com/forum/thread/17586129/routerlayout-causing-page-refresh is an example of the same layout I am using and describes a very similar issue.
I have a base abstract class that extends VerticalLayout and all of the concrete classes extend this base abstract class. Each concrete class defines its own route and use a common layout class.
I have reached out on gitter, vaadin forum and opened a bug in github but no one from Vaadin want to respond to anything as far as I can tell.
Here are the versions of everything I am using:
Vaadin Flow version: 14
Java version: 12.0.1+12
OS version: Mac 10.14.5
Browser version: Fire Fox 70.0.1, Chrome 78.0.3904.97
Code snippets from my implementation:
Main View
#Slf4j
#RoutePrefix("v1/crud")
#Theme(value = Material.class, variant = Material.DARK)
public class MainView extends Div implements RouterLayout {
private H1 h1 = new H1("Vaadin Crud UI");
private HorizontalLayout header = new HorizontalLayout(h1);
private Div content = new Div();
private ApplicationContext context;
#Inject
public MainView(ApplicationContext context) {
this.context = context;
setSizeFull();
h1.setWidthFull();
content.setWidthFull();
header.setWidthFull();
header.setAlignItems(FlexComponent.Alignment.CENTER);
VerticalLayout navigationBar = new VerticalLayout();
navigationBar.setWidth("25%");
navigationBar.add(createNavigationButton("Home", VaadinIcon.HOME, ReportTab.class));
navigationBar.add(createNavigationButton("Batch Search", VaadinIcon.SEARCH, BatchSearchTab.class));
... a bunch more buttons
HorizontalLayout layout = new HorizontalLayout(navigationBar, content);
layout.setWidthFull();
VerticalLayout page = new VerticalLayout(header, layout);
page.setWidthFull();
add(page);
}
#Override
public void showRouterLayoutContent(HasElement hasElement) {
if (hasElement != null) {
Element newElement = hasElement.getElement();
if (newElement != null) {
content.removeAll();
content.getElement().appendChild(newElement);
}
}
}
private Button createNavigationButton(String caption, VaadinIcon icon, Class<? extends BaseEditor> editor) {
Button button = new Button(caption, icon.create());
button.addClickListener(event -> UI.getCurrent().navigate(editor));
button.addThemeVariants(ButtonVariant.MATERIAL_CONTAINED);
button.getStyle().set("background-color", "#00819D");
button.setWidthFull();
return button;
}
}
Base Component:
#Slf4j
#Data
#SpringComponent
#UIScope
public abstract class BaseEditor<P, B> extends VerticalLayout {
private final RememberMeService rememberMe;
private final P businessProcess;
protected Binder<B> binder;
protected Dialog editDialog = new Dialog();
protected Button save = new Button("Save", VaadinIcon.CHECK.create());
protected Button close = new Button("Close", VaadinIcon.EXIT.create());
protected Button delete = new Button("Delete", VaadinIcon.TRASH.create());
protected B bean;
private ChangeHandler changeHandler;
private boolean proceed = true;
public BaseEditor(P businessProcess, RememberMeService rememberMe) {
this.rememberMe = rememberMe;
this.businessProcess = businessProcess;
save.addClickListener(e -> save());
delete.addClickListener(e -> delete());
}
public abstract void delete();
public abstract void save();
protected abstract Component getContent();
protected void edit(B e) {
bean = e;
editDialog.open();
getBinder().setBean(e);
}
protected void initEditorPanel(Component... components) {
HorizontalLayout actions = new HorizontalLayout(save, close, delete);
VerticalLayout data = new VerticalLayout(components);
data.add(actions);
editDialog.removeAll();
editDialog.add(data);
getBinder().bindInstanceFields(this);
close.addClickListener(e -> editDialog.close());
}
public interface ChangeHandler {
void onChange();
}
void setChangeHandler(ChangeHandler h) {
changeHandler = h;
}
void errorDialog(String message) {
final Button close = new Button("Close", VaadinIcon.CLOSE.create());
H3 h3 = new H3(message);
final Dialog errorDialog = new Dialog(h3, close);
errorDialog.open();
close.addClickListener(e -> errorDialog.close());
}
BaseEditor filter(Predicate<B> predicate) {
Objects.requireNonNull(predicate);
proceed = predicate.test(bean);
return this;
}
void buttonConsumer(Consumer<B> consumer) {
if (!proceed) {
proceed = true;
return;
}
try {
consumer.accept(bean);
} catch (Exception e) {
errorDialog(e.getMessage());
} finally {
editDialog.close();
getChangeHandler().onChange();
}
}
void either(Consumer<B> whenTrue, Consumer<B> whenFalse) {
try {
if (proceed) {
whenTrue.accept(bean);
} else {
whenFalse.accept(bean);
}
} catch (Exception e) {
errorDialog(e.getMessage());
} finally {
proceed = true;
editDialog.close();
getChangeHandler().onChange();
}
}
}
Concrete Component:
#Slf4j
#Route(value = "search/batch", layout = MainView.class)
public class BatchSearchTab extends BaseEditor<BatchService, Batch> {
private TextField searchField1;
private TextField searchField2;
public BatchSearchTab(BatchService businessProcess, RememberMeService rememberMe) {
super(businessProcess, rememberMe);
binder = new Binder<>(Batch.class);
save.setIcon(VaadinIcon.REPLY.create());
save.setText("Replay");
delete.setIcon(VaadinIcon.CLOSE.create());
delete.setText("Cancel");
getContent();
}
#Override
public void delete() {
buttonConsumer(b -> getBusinessProcess().cancelBatch(b.getBatchId(), b.getUserAgent()));
}
#Override
public void save() {
filter(b -> b.isReplayable()).buttonConsumer(b -> getBusinessProcess().buildAndSendFile((getBean())));
}
#Override
public void edit(Batch batch) {
HorizontalLayout actions = new HorizontalLayout();
H2 h2 = new H2();
if (batch.isReplayable()) {
h2.setText("Would you like to replay the following.");
actions.add(save, delete, close);
} else {
h2.setText("This record is not eligible for replay.");
actions.add(close);
}
Label batchId = new Label("Correlation Id: " + batch.getBatchId());
Label txnCount = new Label("Transaction Count: " + batch.getTotalTxns());
Label txnAmount = new Label("Total: " + batch.getTotalBatchAmount());
VerticalLayout data = new VerticalLayout(h2, batchId, txnCount, txnAmount, actions);
data.add(actions);
editDialog.removeAll();
editDialog.add(data);
close.addClickListener(e -> editDialog.close());
editDialog.open();
getBinder().setBean(batch);
}
#Override
protected Component getContent() {
final H2 h2 = new H2("Locate Batches");
searchField1 = new TextField("Batch Code");
searchField2 = new TextField("User Agent");
searchField2.addKeyPressListener(Key.ENTER, e -> keyPressListener());
Button searchBtn = new Button("Search", VaadinIcon.SEARCH.create());
HorizontalLayout search = new HorizontalLayout(searchField1, searchField2);
searchBtn.addClickListener(e -> {
search(searchField1.getValue(), searchField2.getValue());
});
add(h2, search, searchBtn);
return this;
}
private void search(String code, String userAgent) {
log.info("Searching {} and {}", code, userAgent);
List<Batch> batches =
getBusinessProcess().getBatchesForUserAgent(code, userAgent, 60);
log.info("Found {} batches", batches.size());
if (batches.size() > 0) {
buildGrid(batches, "BatchId", "totalTxns", "totalBatchAmount", "status");
} else {
errorDialog("No Records found for criteria");
}
}
private void keyPressListener() {
String code = StringUtils.isNotBlank(searchField1.getValue()) ? searchField1.getValue() : null;
if (StringUtils.isNotBlank(searchField2.getValue())) {
search(code, searchField2.getValue());
}
}
private void buildGrid(Collection<Batch> records, String... columns) {
Component result;
if (records.size() == 0) {
result = new Label("NO REPORT DATA AVAILABLE.");
} else {
final Grid<Batch> grid = new Grid<>(Batch.class);
grid.setHeightByRows(records.size() < 10);
grid.setColumns(columns);
grid.setItems(records);
grid.setWidthFull();
grid.asSingleSelect().addValueChangeListener(l -> Optional.ofNullable(l.getValue()).ifPresent(this::edit));
result = grid;
}
if (getComponentCount() < 3) {
add(result);
} else {
replace(getComponentAt(2), result);
}
}
private void loadData(String code, String userAgent) {
if (StringUtils.isNotBlank(code)) {
search(null, userAgent);
} else {
search(code, userAgent);
}
}
}

Disclaimer: some further fact finding happended via IRC
The answer to the question is related to OP running multiple instances of the application behind an round robin load ballancer. The clients hit random servers and therefor had no session running there.
The solution to this is having a shared session store and ideally have the load ballancer dispatch on existing session, so "hot" backend servers get hit.

How to set icons in Tree Grid GXT(GWT) columns?

I am working on GWT app where I should change default icons in Tree Grid to icons from my own. In other cases, I can easily set icons but that is not the case when I have tree grid. When I have just default grid my code for set icon is like this:
Protected List<ColumnConfig> getColumns() {
List<ColumnConfig> columnConfigs = new ArrayList<ColumnConfig>();
ColumnConfig columnConfig = new ColumnConfig("status", MSGS.gridUserColumnHeaderStatus(), 50);
GridCellRenderer<GwtUser> setStatusIcon = new GridCellRenderer<GwtUser>() {
public String render(GwtUser gwtUser, String property, ColumnData config, int rowIndex, int colIndex, ListStore<GwtUser> deviceList, Grid<GwtUser> grid) {
KapuaIcon icon;
if (gwtUser.getStatusEnum() != null) {
switch (gwtUser.getStatusEnum()) {
case DISABLED:
icon = new KapuaIcon(IconSet.USER);
icon.setColor(Color.RED);
break;
case ENABLED:
icon = new KapuaIcon(IconSet.USER);
icon.setColor(Color.GREEN);
break;
default:
icon = new KapuaIcon(IconSet.USER);
icon.setColor(Color.GREY);
break;
}
} else {
icon = new KapuaIcon(IconSet.USER);
icon.setColor(Color.GREY);
}
return icon.getInlineHTML();
}
};
columnConfig.setRenderer(setStatusIcon);
columnConfig.setAlignment(HorizontalAlignment.CENTER);
columnConfig.setSortable(false);
columnConfigs.add(columnConfig);
But when I apply that on my Tree Grid then just first item have an icon, and I can't expand the grid. This is my current code for that Tree Grid
List<ColumnConfig> configs = new ArrayList<ColumnConfig>();
ColumnConfig column = new ColumnConfig("topicName", MSGS.topicInfoTableTopicHeader(), 150);
column.setRenderer(new TreeGridCellRenderer<GwtTopic>());
configs.add(column);
column = new ColumnConfig("timestamp", MSGS.topicInfoTableLastPostedHeader(), 150);
configs.add(column);
store = new TreeStore<GwtTopic>();
AsyncCallback<List<GwtTopic>> topicsCallback = new AsyncCallback<List<GwtTopic>>() {
#Override
public void onSuccess(List<GwtTopic> topics) {
store.add(topics, true);
topicInfoGrid.unmask();
}
#Override
public void onFailure(Throwable t) {
FailureHandler.handle(t);
topicInfoGrid.unmask();
}
};
dataService.findTopicsTree(currentSession.getSelectedAccount().getId(), topicsCallback);
topicInfoGrid = new TreeGrid<GwtTopic>(store, new ColumnModel(configs));
topicInfoGrid.setBorders(false);
topicInfoGrid.setStateful(false);
topicInfoGrid.setLoadMask(true);
topicInfoGrid.mask("Loading");
topicInfoGrid.setStripeRows(true);
topicInfoGrid.getView().setAutoFill(true);
topicInfoGrid.getView().setEmptyText(MSGS.topicInfoGridEmptyText());
topicInfoGrid.disableTextSelection(false);
How to change this code to be able to set my own icons?

You can use the setIconProvider method to change the icon of a leaf:
topicInfoGrid.setIconProvider(new IconProvider<GwtTopic>() {
#Override
public ImageResource getIcon(GwtTopic gwtTopic) {
GwtTopicType type = gwtTopic.getType();
if (type == GwtTopicType.Folder) {
if (topicInfoGrid.isExpanded(gwtTopic)) return new TopicInfoResources.Instance.iconFolderOpen();
else return TopicInfoResources.Instance.iconFolder();
}
return TopicInfoResources.Instance.user();
}
});
And this is your interface that extends ClientBundle:
public interface TopicInfoResources extends ClientBundle
{
public static final TopicInfoResources Instance = GWT.create(TopicInfoResources.class);
#Source("folder.png") ImageResource iconFolder();
#Source("folder-open.png") ImageResource iconFolderOpen();
#Source("user.png") ImageResource user();
}
Hope this helps!

Disabling or Intercepting a Drop Outside Of A Window

I've implemented a set of draggable tabs, following the form of this example:
How to implement draggable tab using Java Swing?
Everything appears to work as I desire, however,when I drag outside of the main panel, the desktop will become a valid drop target (the resulting drop is accepted and marked successful).
Is there a way to intercept this drop to react to dropping outside of our root pane? It's simple enough to detect, but it's not clear to me how to actually capture the drop before the outside world does.
By the time DragSourceListener's dragDropEnd is called, the drop is already executed and there doesn't appear to be a good way to end dragging in dragOver/Exit/Whatever.
Gee, it'd be nice if something like this worked:
#Override
public void dragOver(DragSourceDragEvent dragEvent)
{
DragEnabledTabTransferData data = getTabTransferData(dragEvent);
DragSourceContext dragSourceContext = dragEvent.getDragSourceContext();
if (data == null)
{
dragSourceContext.setCursor(DragSource.DefaultMoveNoDrop);
return;
}
if (!data.getTabbedPane().getRootPane().getBounds().contains(dragEvent.getLocation()))
{
dragSourceContext.dragDropEnd(new DragSourceDropEvent(dragSourceContext, 999, true));
}
}
Instead the drag continues dragging along. I do, however get a dragDropEnd for my troubles.
Any ideas? I'd be pretty sad to hear that the only solution would be to have some hidden maximized global pane that acted only as a drop target to capture out-of-window events.
Here is a working example. If you drag a tab out to, say, the desktop in Linux, it'll try to cast the transfer data into a Serializable and not be happy. The drag over I was playing with is commented with "This is where I'd assume we'd be able to intercept stuff" if you want to jump straight to what I'd pointed to above.
/** "Simple" example of DnD tabbed panes. Sourced from Eugene Yokota:
* http:stackoverflow.com/questions/60269/how-to-implement-draggable-tab-using-java-swing */
import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.dnd.*;
import javax.swing.*;
public class DnDTabbedPane extends JTabbedPane {
private static final String NAME = "TabTransferData";
private final DataFlavor FLAVOR = new DataFlavor(DataFlavor.javaJVMLocalObjectMimeType, NAME);
public DnDTabbedPane() {
super();
final DragSourceListener dsl = new DragSourceListener() {
public void dragEnter(DragSourceDragEvent e) {
e.getDragSourceContext().setCursor(DragSource.DefaultMoveDrop);
}
public void dragExit(DragSourceEvent e) {
e.getDragSourceContext().setCursor(DragSource.DefaultMoveNoDrop);
}
/**
* This is where I'd assume we'd be able to intercept stuff
* so drops don't happen where we don't want them to.
*/
public void dragOver(DragSourceDragEvent e) {
TabTransferData data = getTabTransferData(e);
if (data == null) {
e.getDragSourceContext().setCursor(DragSource.DefaultMoveNoDrop);
return;
}
//This is where I ended up robokilling the drag via hackery
e.getDragSourceContext().setCursor(DragSource.DefaultMoveDrop);
}
public void dragDropEnd(DragSourceDropEvent e) {}
public void dropActionChanged(DragSourceDragEvent e) {}
};
final DragGestureListener dgl = new DragGestureListener() {
public void dragGestureRecognized(DragGestureEvent e) {
Point tabPt = e.getDragOrigin();
int dragTabIndex = indexAtLocation(tabPt.x, tabPt.y);
if (dragTabIndex < 0) {
return;
}
e.startDrag(DragSource.DefaultMoveDrop,new TabTransferable(DnDTabbedPane.this, dragTabIndex), dsl);
}
};
new DropTarget(this, DnDConstants.ACTION_COPY_OR_MOVE, new CDropTargetListener(), true);
new DragSource().createDefaultDragGestureRecognizer(this, DnDConstants.ACTION_COPY_OR_MOVE, dgl);
}
private TabTransferData getTabTransferData(DropTargetDropEvent a_event) {
try {
return (TabTransferData) a_event.getTransferable().getTransferData(FLAVOR);
} catch (Exception e) {}
return null;
}
private TabTransferData getTabTransferData(DropTargetDragEvent a_event) {
try {
return (TabTransferData) a_event.getTransferable().getTransferData(FLAVOR);
} catch (Exception e) {}
return null;
}
private TabTransferData getTabTransferData(DragSourceDragEvent a_event) {
try {
return (TabTransferData) a_event.getDragSourceContext().getTransferable().getTransferData(FLAVOR);
} catch (Exception e) {}
return null;
}
class TabTransferable implements Transferable {
private TabTransferData m_data = null;
private DataFlavor[] flavors = {FLAVOR};
public TabTransferable(DnDTabbedPane a_tabbedPane, int a_tabIndex) {
m_data = new TabTransferData(DnDTabbedPane.this, a_tabIndex);
}
public Object getTransferData(DataFlavor flavor) {
return m_data;
}
public DataFlavor[] getTransferDataFlavors() {
return flavors;
}
public boolean isDataFlavorSupported(DataFlavor flavor) {
return flavor.getHumanPresentableName().equals(NAME);
}
}
class TabTransferData {
DnDTabbedPane m_tabbedPane = null;
int m_tabIndex = -1;
public TabTransferData(DnDTabbedPane a_tabbedPane, int a_tabIndex) {
m_tabbedPane = a_tabbedPane;
m_tabIndex = a_tabIndex;
}
}
class CDropTargetListener implements DropTargetListener {
public void dragEnter(DropTargetDragEvent e) {
if (isDragAcceptable(e)) {
e.acceptDrag(e.getDropAction());
} else {
e.rejectDrag();
}
}
public void drop(DropTargetDropEvent a_event) {
if (isDropAcceptable(a_event)) {
convertTab(getTabTransferData(a_event),
getTargetTabIndex(a_event.getLocation()));
a_event.dropComplete(true);
} else {
a_event.dropComplete(false);
}
}
private boolean isTransferableGood(Transferable t, DataFlavor flavor)
{
return t == null || t.isDataFlavorSupported(flavor);
}
private boolean isDataGood(TabTransferData data)
{
if (DnDTabbedPane.this == data.m_tabbedPane && data.m_tabIndex >= 0) {
return true;
}
return false;
}
public boolean isDragAcceptable(DropTargetDragEvent e) {
Transferable t = e.getTransferable();
if (!isTransferableGood(t, e.getCurrentDataFlavors()[0])) {
return false;
}
return isDataGood(getTabTransferData(e));
}
public boolean isDropAcceptable(DropTargetDropEvent e) {
Transferable t = e.getTransferable();
if (!isTransferableGood(t, e.getCurrentDataFlavors()[0])) {
return false;
}
return isDataGood(getTabTransferData(e));
}
public void dragExit(DropTargetEvent e) {}
public void dropActionChanged(DropTargetDragEvent e) {}
public void dragOver(final DropTargetDragEvent e) {}
}
private int getTargetTabIndex(Point a_point) {
for (int i = 0; i < getTabCount(); i++) {
Rectangle r = getBoundsAt(i);
r.setRect(r.x - r.width / 2, r.y, r.width, r.height);
if (r.contains(a_point)) {
return i;
}
}
return -1;
}
private void convertTab(TabTransferData a_data, int a_targetIndex) {
DnDTabbedPane source = a_data.m_tabbedPane;
int sourceIndex = a_data.m_tabIndex;
if (sourceIndex < 0) {
return;
}
Component cmp = source.getComponentAt(sourceIndex);
String str = source.getTitleAt(sourceIndex);
if (a_targetIndex < 0 || sourceIndex == a_targetIndex) {
return;
}
source.remove(sourceIndex);
if (a_targetIndex == getTabCount()) {
addTab(str, cmp);
} else if (sourceIndex > a_targetIndex) {
insertTab(str, null, cmp, null, a_targetIndex);
} else {
insertTab(str, null, cmp, null, a_targetIndex - 1);
}
}
public static void main(String[] args)
{
JFrame window = new JFrame();
DnDTabbedPane tabbedPane = new DnDTabbedPane();
for(int i=0; i< 5; i++)
{
tabbedPane.addTab("I'm tab "+i, new JLabel("I'm tab "+i));
}
window.add(tabbedPane);
window.setSize(400, 200);
window.setVisible(true);
}
}
Thus far, the best I can do is call something to this effect when we hop out of the parent.
Component rootPane = SwingUtilities.getRoot(component);
Rectangle bounds = rootPane.getBounds();
if (!bounds.contains(location))
{
Robot robot = null;
try
{
robot = new Robot();
} catch (AWTException e)
{
return;
}
robot.keyPress(KeyEvent.VK_ESCAPE);
robot.keyRelease(KeyEvent.VK_ESCAPE);
}
It's a total hack, and doesn't solve my issue. I'd like to intercept the final drop event, see if it was outside of the frame and spawn the tab in its own JFrame.
If I was using the NetBeans, MyDoggy, or Eclipse frameworks, I guess this would all be magically handled for me. Alas.

There is no Way to Cancel the Drag directly. see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4502185
I would prefer to show the User that Drop on Desktop is not allowed, by changing the Cursor.
Your DragSourceListener dsl has in the dragOver method a DragSourceDragEvent which tells you
that the target action is NONE over the Desktop.
Change to this:
public void dragOver(DragSourceDragEvent e) {
TabTransferData data = getTabTransferData(e);
if( data == null || e.getTargetActions() == DnDConstants.ACTION_NONE ) {
e.getDragSourceContext().setCursor( DragSource.DefaultMoveNoDrop );
return;
}
e.getDragSourceContext().setCursor( DragSource.DefaultMoveDrop);
}
If you really want to Cancel, than you have to use your ESC solution or something like that:
try {
new Robot().mouseRelease( InputEvent.BUTTON1_MASK ); // if Button1 was the only Button to start a Drag
} catch( AWTException e1 ) {
}

As confirmed by #oliholz, there just isn't a way to do it without having to force a cancel via a keystroke.
However, for my needs of creating a tear-off tab, I found that creating a floating pane that was, itself, a drop target listener felt like the cleanest solution:
package com.amish.whatever;
import java.awt.MouseInfo;
import java.awt.Point;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DropTarget;
import java.awt.dnd.DropTargetDragEvent;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.dnd.DropTargetEvent;
import java.awt.dnd.DropTargetListener;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JLabel;
import javax.swing.JWindow;
import javax.swing.Timer;
public class TearAwayTab extends JWindow {
MousePoller mousePoller = new MousePoller();
public TearAwayTab() {
this.add(new JLabel("FLONT"));
this.pack();
new DropTarget(this, DnDConstants.ACTION_COPY_OR_MOVE, new EasyDropTarget(), true);
this.setVisible(false);
}
private void center(Point location)
{
Point center = new Point();
center.setLocation(location.x-this.getWidth()/2, location.y-this.getHeight()/2);
TearAwayTab.this.setLocation(center);
}
public void attach(Point location)
{
center(location);
mousePoller.start();
this.setVisible(true);
}
public void detach()
{
mousePoller.stop();
this.setVisible(false);
}
private int DELAY = 10;
private class MousePoller extends Timer{
public MousePoller(){
super(DELAY, new ActionListener() {
private Point lastPoint = MouseInfo.getPointerInfo().getLocation();
#Override
public void actionPerformed(ActionEvent e) {
Point point = MouseInfo.getPointerInfo().getLocation();
if (!point.equals(lastPoint)) {
center(point);
}
lastPoint = point;
}
});
}
}
private class EasyDropTarget implements DropTargetListener
{
#Override
public void dragEnter(DropTargetDragEvent dtde) {
dtde.acceptDrag(dtde.getDropAction());
}
#Override
public void dragOver(DropTargetDragEvent dtde) {}
#Override
public void dropActionChanged(DropTargetDragEvent dtde) {}
#Override
public void dragExit(DropTargetEvent dte) {}
#Override
public void drop(DropTargetDropEvent dtde) {
dtde.dropComplete(true);
detach();
System.out.println("DROP Intercepted");
}
}
}
The bit with the MousePoller works around scrubbing the mouse too fast for mouse listeners to reliably update the location. I'd tried with a motion listener and was able to escape the bounds of the floater quite easily.
Back in the first example, I now include the tear away tab as a private member of the tabbed pane, and call attach and detach when exiting or entering my drop areas:
final DragSourceListener dsl = new DragSourceListener() {
public void dragEnter(DragSourceDragEvent e) {
e.getDragSourceContext().setCursor(DragSource.DefaultMoveDrop);
Rectangle bounds = SwingUtilities.getRoot(DnDTabbedPane.this).getBounds();
if(bounds.contains(e.getLocation())){
tearTab.detach();
}
}
public void dragExit(DragSourceEvent e) {
e.getDragSourceContext().setCursor(DragSource.DefaultMoveNoDrop);
tearTab.attach(e.getLocation());
}
...
This also has the added benefit of preserving the DnD operation in the case of dragging out, and then back in.
Thanks for the input. If you have any other ideas/comments, I'm all ears.

This doesn't directly relate to tabs, but one way to stop drags from being able to be dragged to the desktop is to wrap whatever you're dragging in a custom wrapper class. Then, when you make your TransferHandler, make a DataFlavor localFlavor = new ActivationDataFlavor(YourWrapperClass.class, DataFlavor.javaJVMLocalObjectMimeType, "description"); Next, override the createTransferable method to have new DataHandler(passedInComponent, localFlavor.getMimeType()); and return a new Transferable in which you've overridden all the methods to only have your localFlavor. Finally, in the importData method, make sure to import your data as your localFlavor type. This will prevent dragging to the deaktop as the flavor you defined is local to the JVM.

Eclipse RCP: Generating views from form values

I want to build a user interface similar to the sketch below:
When the user fills out the form on the right and clicks the 'Plot!' button, a new closeable tab opens on the left with a chart.
I am new to RCP and have been following this tutorial. I am able to bring up tabs with charts triggered from a menu item. How do I go about:
creating the tab (view?) with the form
open a new chart tab when the user clicks the button
Edit
Here is my current code. It satisfies the basic requirements outlined in this question, but I am not sure if that is the best approach. I would be delighted if someone here can guide me in the right direction.
A view with the form; the button's listener invokes a command.
public class FormView extends ViewPart {
public static final String ID =
FormView.class.getPackage().getName() + ".Form";
private FormToolkit toolkit;
private Form form;
public Text text;
#Override
public void createPartControl(Composite parent) {
toolkit = new FormToolkit(parent.getDisplay());
form = toolkit.createForm(parent);
form.setText("Pie Chucker");
GridLayout layout = new GridLayout();
form.getBody().setLayout(layout);
layout.numColumns = 2;
GridData gd = new GridData();
gd.horizontalSpan = 2;
Label label = new Label(form.getBody(), SWT.NULL);
label.setText("Chart Title:");
text = new Text(form.getBody(), SWT.BORDER);
text.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
Button button = new Button(form.getBody(), SWT.PUSH);
button.setText("Plot");
gd = new GridData();
gd.horizontalSpan = 2;
button.setLayoutData(gd);
button.addMouseListener(new MouseAdapter() {
#Override
public void mouseDown(MouseEvent e) {
IHandlerService handlerService = (IHandlerService) getSite()
.getService(IHandlerService.class);
try {
handlerService.executeCommand(ShowChartHandler.ID, null);
} catch (Exception ex) {
throw new RuntimeException(ShowChartHandler.ID +
" not found");
}
}
});
}
#Override
public void setFocus() {
}
}
The command invoked by the button from the form. This opens a new view with a chart.
public class ShowChartHandler extends AbstractHandler implements IHandler {
public static final String ID =
ShowChartHandler.class.getPackage().getName() + ".ShowChart";
private int count = 0;
#Override
public Object execute(ExecutionEvent event) throws ExecutionException {
IWorkbenchWindow window = HandlerUtil.getActiveWorkbenchWindow(event);
try {
window.getActivePage().showView(ChartView.ID,
String.valueOf(++count), IWorkbenchPage.VIEW_ACTIVATE);
} catch (PartInitException e) {
e.printStackTrace();
}
return null;
}
}
The view with the chart. It looks up the form view and reads a value from a text field in the form (?!):
public class ChartView extends ViewPart {
public static final String ID =
ChartView.class.getPackage().getName() + ".Chart";
private static final Random random = new Random();
public ChartView() {
// TODO Auto-generated constructor stub
}
#Override
public void createPartControl(Composite parent) {
FormView form =
(FormView) Workbench.getInstance()
.getActiveWorkbenchWindow()
.getActivePage()
.findView(FormView.ID);
String title = form == null? null : form.text.getText();
if (title == null || title.trim().length() == 0) {
title = "Pie Chart";
}
setPartName(title);
JFreeChart chart = createChart(createDataset(), title);
new ChartComposite(parent, SWT.NONE, chart, true);
}
#Override
public void setFocus() {
// TODO Auto-generated method stub
}
/**
* Creates the Dataset for the Pie chart
*/
private PieDataset createDataset() {
Double[] nums = getRandomNumbers();
DefaultPieDataset dataset = new DefaultPieDataset();
dataset.setValue("One", nums[0]);
dataset.setValue("Two", nums[1]);
dataset.setValue("Three", nums[2]);
dataset.setValue("Four", nums[3]);
dataset.setValue("Five", nums[4]);
dataset.setValue("Six", nums[5]);
return dataset;
}
private Double[] getRandomNumbers() {
Double[] nums = new Double[6];
int sum = 0;
for (int i = 0; i < 5; i++) {
int r = random.nextInt(20);
nums[i] = new Double(r);
sum += r;
}
nums[5] = new Double(100 - sum);
return nums;
}
/**
* Creates the Chart based on a dataset
*/
private JFreeChart createChart(PieDataset dataset, String title) {
JFreeChart chart = ChartFactory.createPieChart(title, // chart title
dataset, // data
true, // include legend
true, false);
PiePlot plot = (PiePlot) chart.getPlot();
plot.setSectionOutlinesVisible(false);
plot.setLabelFont(new Font("SansSerif", Font.PLAIN, 12));
plot.setNoDataMessage("No data available");
plot.setCircular(false);
plot.setLabelGap(0.02);
return chart;
}
}
The perspective that ties it all together:
public class Perspective implements IPerspectiveFactory {
public void createInitialLayout(IPageLayout layout) {
layout.setEditorAreaVisible(false);
layout.addStandaloneView(FormView.ID, false,
IPageLayout.RIGHT, 0.3f,
IPageLayout.ID_EDITOR_AREA);
IFolderLayout charts = layout.createFolder("Charts",
IPageLayout.LEFT, 0.7f, FormView.ID);
charts.addPlaceholder(ChartView.ID + ":*");
}
}

I would recommend a different aproach. Eclipse has viewparts (views) and editors. It is easy to open multiple editors. Views are not so much for open multiple ones.
So my suggestion is, that you implement the part you call "FormView" as a StandAloneView and implement the "ChartView" as an editor.
I would also recommend to use a different listener for the button, so also the code will be executed when using the keyboard to click the button.
My proposal:
public class FormView extends ViewPart {
...
button.addSelectionListener(new SelectionAdapter() {
#Override
public void widgetSelected(SelectionEvent e) {
// this below can also be called by a command but you need to take care about the data, which the user put into the fields in different way.
Shell shell = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell();
IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
IWorkbenchPage page = window.getActivePage();
ChartEditorInput input = new ChartEditorInput(text.getText(),...<other data you need to pass>);
try {
page.openEditor(input, ChartEditor.ID);
} catch (PartInitException e) {
e.printStackTrace();
}
}
});
ChartView needs to be changed to ChartEditor. See here http://www.vogella.de/articles/RichClientPlatform/article.html#editor_editorinput how that is done.
ChartEditorInput hereby is a class you need to implement aside the editor class, which holds the data.
In your perspective you call:
public void createInitialLayout(IPageLayout layout) {
String editorArea = layout.getEditorArea();
layout.setFixed(false);
layout.setEditorAreaVisible(true);
layout.addStandaloneView("your.domain.and.FormView", true,IPageLayout.RIGHT, 0.15f, editorArea);
Hope this helps!