private void beginDrag(Event evt) {
String docId = initDragParams_.getDocId();
int dragTabWidth = initDragWidth_;
// set drag element state
dragTabsHost_ = getTabBarElement();
dragScrollHost_ = dragTabsHost_.getParentElement();
outOfBounds_ = 0;
candidatePos_ = null;
startPos_ = null;
// attempt to determine which tab the cursor is over
Point hostPos = DomUtils.getRelativePosition(Document.get().getBody(), dragTabsHost_);
int dragX = evt.getClientX() - hostPos.getX();
for (int i = 0; i < dragTabsHost_.getChildCount(); i++) {
Node node = dragTabsHost_.getChild(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
int left =
DomUtils.leftRelativeTo(dragTabsHost_, Element.as(node))
- dragScrollHost_.getScrollLeft();
int right = left + Element.as(node).getOffsetWidth();
if (left <= dragX && dragX <= right) {
candidatePos_ = i;
break;
}
}
}
// let the rest of the IDE know we're dragging (this will enable us to
// disable drag targets that might otherwise be happy to accept the
// data)
curState_ = STATE_DRAGGING;
events_.fireEvent(
new DocTabDragStateChangedEvent(DocTabDragStateChangedEvent.STATE_DRAGGING));
// the relative position of the last node determines how far we
// can drag
dragMax_ =
DomUtils.leftRelativeTo(dragTabsHost_, getLastChildElement(dragTabsHost_))
+ getLastChildElement(dragTabsHost_).getClientWidth();
lastCursorX_ = evt.getClientX();
// account for cursor starting out of bounds (e.g. dragging into
// empty space on the right of the panel)
if (lastCursorX_ > dragMax_ + (initDragParams_.getCursorOffset()))
outOfBounds_ = (lastCursorX_ - dragMax_) - initDragParams_.getCursorOffset();
// attempt to ascertain whether the element being dragged is one of
// our own documents
for (DocTab tab : docTabs_) {
if (tab.getDocId() == docId) {
dragElement_ = tab.getElement().getParentElement().getParentElement();
break;
}
}
// if we couldn't find the horizontal drag position in any tab, append
// to the end
if (candidatePos_ == null) {
candidatePos_ = dragTabsHost_.getChildCount();
}
destPos_ = candidatePos_;
// if we're dragging one of our own documents, figure out its physical
// position
if (dragElement_ != null) {
for (int i = 0; i < dragTabsHost_.getChildCount(); i++) {
if (dragTabsHost_.getChild(i) == dragElement_) {
startPos_ = i;
break;
}
}
}
// compute the start location for the drag
if (candidatePos_ >= dragTabsHost_.getChildCount()) {
Element lastTab = getLastChildElement(dragTabsHost_);
lastElementX_ = DomUtils.leftRelativeTo(dragTabsHost_, lastTab) + lastTab.getOffsetWidth();
} else {
lastElementX_ =
DomUtils.leftRelativeTo(
dragTabsHost_, Element.as(dragTabsHost_.getChild(candidatePos_)));
}
// if we're dragging one of our own tabs, snap it out of the
// tabset
if (dragElement_ != null) {
dragElement_.getStyle().setPosition(Position.ABSOLUTE);
dragElement_.getStyle().setLeft(lastElementX_, Unit.PX);
dragElement_.getStyle().setZIndex(100);
Scheduler.get()
.scheduleDeferred(
new ScheduledCommand() {
@Override
public void execute() {
dragElement_.getStyle().setDisplay(Display.NONE);
}
});
}
// create the placeholder that shows where this tab will go when the
// mouse is released
dragPlaceholder_ = Document.get().createDivElement();
dragPlaceholder_.getStyle().setWidth(dragTabWidth - 4, Unit.PX);
dragPlaceholder_.getStyle().setHeight(dragTabsHost_.getClientHeight() - 3, Unit.PX);
dragPlaceholder_.getStyle().setDisplay(Display.INLINE_BLOCK);
dragPlaceholder_.getStyle().setPosition(Position.RELATIVE);
dragPlaceholder_.getStyle().setFloat(Float.LEFT);
dragPlaceholder_.getStyle().setBorderStyle(BorderStyle.DOTTED);
dragPlaceholder_.getStyle().setBorderColor("#A1A2A3");
dragPlaceholder_.getStyle().setBorderWidth(1, Unit.PX);
dragPlaceholder_.getStyle().setMarginLeft(1, Unit.PX);
dragPlaceholder_.getStyle().setMarginRight(1, Unit.PX);
dragPlaceholder_.getStyle().setProperty("borderTopLeftRadius", "4px");
dragPlaceholder_.getStyle().setProperty("borderTopRightRadius", "4px");
dragPlaceholder_.getStyle().setProperty("borderBottom", "0px");
if (candidatePos_ < dragTabsHost_.getChildCount()) {
dragTabsHost_.insertBefore(dragPlaceholder_, dragTabsHost_.getChild(candidatePos_));
} else {
dragTabsHost_.appendChild(dragPlaceholder_);
}
}
public void ensureSelectedTabIsVisible(boolean animate) {
if (currentAnimation_ != null) {
currentAnimation_.cancel();
currentAnimation_ = null;
}
Element selectedTab =
(Element)
DomUtils.findNode(
getElement(),
true,
false,
new NodePredicate() {
public boolean test(Node n) {
if (n.getNodeType() != Node.ELEMENT_NODE) return false;
return ((Element) n).getClassName().contains("gwt-TabLayoutPanelTab-selected");
}
});
if (selectedTab == null) {
return;
}
selectedTab = selectedTab.getFirstChildElement().getFirstChildElement();
Element tabBar = getTabBarElement();
if (!isVisible() || !isAttached() || tabBar.getOffsetWidth() == 0) return; // not yet loaded
final Element tabBarParent = tabBar.getParentElement();
final int start = tabBarParent.getScrollLeft();
int end =
DomUtils.ensureVisibleHoriz(
tabBarParent, selectedTab, padding_, padding_ + rightMargin_, true);
// When tabs are closed, the overall width shrinks, and this can lead
// to cases where there's too much empty space on the screen
Node lastTab = getLastChildElement(tabBar);
if (lastTab == null || lastTab.getNodeType() != Node.ELEMENT_NODE) return;
int edge =
DomUtils.getRelativePosition(tabBarParent, Element.as(lastTab)).x
+ Element.as(lastTab).getOffsetWidth();
end = Math.min(end, Math.max(0, edge - (tabBarParent.getOffsetWidth() - rightMargin_)));
if (edge <= tabBarParent.getOffsetWidth() - rightMargin_) end = 0;
if (start != end) {
if (!animate) {
tabBarParent.setScrollLeft(end);
} else {
final int finalEnd = end;
currentAnimation_ =
new Animation() {
@Override
protected void onUpdate(double progress) {
double delta = (finalEnd - start) * progress;
tabBarParent.setScrollLeft((int) (start + delta));
}
@Override
protected void onComplete() {
if (this == currentAnimation_) {
tabBarParent.setScrollLeft(finalEnd);
currentAnimation_ = null;
}
}
};
currentAnimation_.run(Math.max(200, Math.min(1500, Math.abs(end - start) * 2)));
}
}
}