我正在捕获右键单击事件以显示上下文菜单。我无法弄清楚的是,在显示上下文菜单之前,如何通过右键单击实际选择 TreeItem。
感谢所有帮助。
private Tree tree = new Tree() {
@Override
public void onBrowserEvent(Event event) {
if (event.getTypeInt() == Event.ONCONTEXTMENU) {
DOM.eventPreventDefault(event);
showContextMenu(event);
}
super.onBrowserEvent(event);
}
@Override
protected void setElement(Element elem) {
super.setElement(elem);
sinkEvents(Event.ONCONTEXTMENU);
}
};
ONMOUSEDOWN 事件在 ONCONTEXTMENU 之前触发。您是否尝试过监听 onMouseDown 事件并设置所选项目?沿着这些思路:
@Override
public void onBrowserEvent(Event event) {
switch (DOM.eventGetType(event)) {
case Event.ONMOUSEDOWN:
if (DOM.eventGetButton(event) == Event.BUTTON_RIGHT) {
TreeItem selectedItem = findSelectedItem(event);
if (selectedItem != null) {
selectedItem.setSelected(true);
}
} else {
super.onBrowserEvent(event);
}
break;
case Event.ONCONTEXTMENU:
showContextMenu(event);
break;
default:
super.onBrowserEvent(event);
break;
}
findSelectedItem 遍历树查找所选项目:
TreeItem findSelectedItem(Event e) {
return findSelectedItemRecursive(event.getClientX(), event.getClientY());
}
TreeItem findSelectedTreeItemRecursive(TreeItem root, int x, int y) {
if (null == root) {
int count = getItemCount();
for (int i = 0; i < count; i++) {
TreeItem selected = findSelectedTreeItemRecursive(getItem(i), x, y);
if (selected != null) {
return selected;
}
}
return null;
}
int count = item.getChildCount();
for (int i = 0; i < count; i++) {
TreeItem selected = findSelectedTreeItem(item.getChild(i), x, y);
if (selected != null) {
return selected;
}
}
if (x >= item.getAbsoluteLeft()
&& x <= item.getAbsoluteLeft() + item.getOffsetWidth()
&& y >= item.getAbsoluteTop()
&& y <= item.getAbsoluteTop() + item.getOffsetHeight()) {
return item;
}
return null;
}
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