How to Get Checked items in CheckBox TreeView in JavaFx?
I don't know how to achieve this... You only get the selected items...
ObservableList<TreeItem<String>> items = treeHazardsXmi.getSelectionModel().getSelectedItems();
Assuming you are using CheckBoxTreeItems, you can iterate through the tree and test each one's selected property:
ObservableSet<CheckBoxTreeItem<?>> checkedItems = FXCollections.observableHashSet();
findCheckedItems((CheckBoxTreeItem<?>) tree.getRoot(), checkedItems);
// ...
private void findCheckedItems(CheckBoxTreeItem<?> item, ObservableSet<CheckBoxTreeItem<?>> checkedItems) {
if (item.isSelected()) {
checkedItems.add(item);
}
for (TreeItem<?> child : item.getChildren()) {
findCheckedItems((CheckBoxTreeItem<?>) child, checkedItems);
}
}
If you have a very large tree, for which that is computationally prohibitive, you can maintain a set of checked items, and by observing each item's selectedProperty, keep the set updated at all times. The downside here is that you have to be vigilant to always create the CheckBoxTreeItem so that it updates the set:
private ObservableSet<CheckBoxTreeItem<?>> checkedItems = FXCollections.observableHashSet();
private <T> CheckBoxTreeItem<T> createTreeItem(T value) {
CheckBoxTreeItem<T> item = new CheckBoxTreeItem<>(value);
item.selectedProperty().addListener((obs, wasChecked, isNowChecked) -> {
if (isNowChecked) {
checkedItems.add(item);
} else {
checkedItems.remove(item);
}
});
return item ;
}
Now, as long as your items are created via the createTreeItem() method, the checkedItems set will always contain the checked items.
Note that if your tree is dynamic (you add and remove nodes at runtime), you should go further and deregister the listener if the item is removed from the tree (left as an exercise for the reader...).
Related
I'm working in flex and I made a custom drop down where there are check boxes to allow the user to select multiple options. I used this template.
However this does not have scrolling because if you allow scrolling for some reason the checkboxes start to mess up. For instance if you have options 1 to 8 and only 1 to 5 are shown. You select option 1 and then scroll down to select option 7. When you scroll up the checkboxes start to switch around like option 3 all of a sudden is showing selected. Keep scrolling up and down and the checkbox selection just changes on it's own. I think this is a rendering issue and the actual selection data isn't changed at all (it knows only option 1 and option 7 were selected). Any ideas on how to fix this?
public function onOpen(event:DropDownEvent):void
{//load the checkboxes and set the mouse tracker
activateAllCheckBoxes();
this.scroller.verticalScrollBar.addEventListener(Event.CHANGE, list_verticalScrollBar_change);
callLater(observeMouse);
}
private function list_verticalScrollBar_change(evt:Event):void
{
//currentlySelectedCheckBoxes = selectedCheckboxes;
UpdateCheckBoxesWhenScrolling();
selectedIndex = -1;
}
protected function UpdateCheckBoxesWhenScrolling():void
{
for (var c:int = 0; c < dataGroup.numElements; c++) {
var obj:DropDownCheckBox = dataGroup.getElementAt(c) as DropDownCheckBox;
if(obj!=null)
{
var judgDebtorFromCheckBox:JudgDebtor = (obj.data) as JudgDebtor;
if(FindInCurrentList(judgDebtorFromCheckBox.JudgmentDebtorId)>0)
{
obj.checkbox.selected = true;
}
else
{
obj.checkbox.selected = false;
}
}
}
}
private function FindInCurrentList(ID:int):int
{
for(var i:int=0;i<currentlySelectedCheckBoxes.length;i++)
{
var JD:JudgDebtor = currentlySelectedCheckBoxes.getItemAt(i) as JudgDebtor;
if(JD.JudgmentDebtorId == ID)
return 1;
}
return -1;
}
So above code I register a scroll event listener on the drop down. It will update the drop down entries which has a check box and it uses an array collection called: currentlySelectedCheckBoxes. I debug the UpdateCheckBoxesWhenScrolling function and it's working fine, in other words it will check off the ones selected but for some reason it still is showing the wrong results for instance 11 entries in the list and only the second one is selected I scroll down and I can't see the the second entry but all of a sudden the last entry is showing that it's checked off.
This happens because the drop down list reuses the renderers when you scroll. For example if you have checked 1st item and scroll, the renderer for that is reused to display the item that becomes visible when you scroll. So the last item shows as checked. To avoid messing up the selection, you will have to do the following in the renderer that you are using
override public function set data(value:Object):void
{
super.data = value;
//inspect the property which indicates whether to select the checkbox or not
//and set the value of selected property accordingly
}
Hope this helps
So here's my screnario. I have a toolbar at the top (office style), with buttons. This is hosted in a shell. Some of those buttons are applicable only to certain child view models as they get loaded. Ideally what I would like to happen is have the buttons action.target repositioned to child view model as it gets created (I kind of got this working by settings Action.Target="ActiveItem" on them. This doesn't solve the problem fully though:
a) When the child viewmodel is closed and there is no active item, I want them to reposition to Shell as the target so they can be set to "default" state.
b) I noticed that when child viewmodel is closed and the shell being the conductor has it ActiveItem=null, the hooks from the action are still bound to the living instance of the last viewmodel, so doesn't looks like it got disposed of. Memory leak?
Any suggestions how to implement this scenario?
What about adding a property to your ShellViewModel which points to the action target and updating it when stuff gets activated/deactivated:
e.g.
public class ShellViewModel
{
public object ActionTarget
{
get { return _actionTarget; }
set
{
_actionTarget = value;
NotifyOfPropertyChange(() => ActionTarget);
}
}
// Then when the active item changes just update the target:
public override NotifyOfPropertyChange(string propertyName)
{
if(propertyName == "ActiveItem")
{
if(ActiveItem == null) ActionTarget = this;
else ActionTarget = ActiveItem;
}
}
}
Now bind to that:
<SomeMenu cal:Action.Target="{Binding ActionTarget}" />
Not sure if that will work or not but I'm sure I've done something similar in the past. (You may also have to explicitly call NPC on your actions before they will update after you have changed ActiveItem)
I have a simple list and a background refresh protocol.
When the list is scrolled down, the refresh scrolls it back to the top. I want to stop this.
I have tried catching the COLLECTION_CHANGE event and
validateNow(); // try to get the component to reset to the new data
list.ensureIndexIsVisible(previousIndex); // actually, I search for the previous data id in the IList, but that's not important
This fails because the list resets itself after the change (in DataGroup.commitProperties).
I hate to use a Timer, ENTER_FRAME, or callLater(), but I cannot seem to figure out a way.
The only other alternatives I can see is sub-classing the List so it can catch the dataProviderChanged event the DataGroup in the skin is throwing.
Any ideas?
Actually MUCH better solution to this is to extend DataGroup. You need to override this.
All the solutions here create a flicker as the scrollbar gets resetted to 0 and the it's set back to the previous value. That looks wrong. This solution works without any flicker and the best of all, you just change DataGroup to FixedDataGroup in your code and it works, no other changes in code are needed ;).
Enjoy guys.
public class FixedDataGroup extends spark.components.DataGroup
{
private var _dataProviderChanged:Boolean;
private var _lastScrollPosition:Number = 0;
public function FixedDataGroup()
{
super();
}
override public function set dataProvider(value:IList):void
{
if ( this.dataProvider != null && value != this.dataProvider )
{
dataProvider.removeEventListener(CollectionEvent.COLLECTION_CHANGE, onDataProviderChanged);
}
super.dataProvider = value;
if ( value != null )
{
value.addEventListener(CollectionEvent.COLLECTION_CHANGE, onDataProviderChanged);
}
}
override protected function commitProperties():void
{
var lastScrollPosition:Number = _lastScrollPosition;
super.commitProperties();
if ( _dataProviderChanged )
{
verticalScrollPosition = lastScrollPosition;
}
}
private function onDataProviderChanged(e:CollectionEvent):void
{
_dataProviderChanged = true;
invalidateProperties();
}
override public function set verticalScrollPosition(value:Number):void
{
super.verticalScrollPosition = value;
_lastScrollPosition = value;
}
}
I ll try to explain my approach...If you are still unsure let me know and I ll give you the source code as well.
1) Create a variable to store the current scroll position of the viewport.
2) Add Event listener for Event.CHANGE and MouseEvent.MOUSE_WHEEL on the scroller and update the variable created in step 1 with the current scroll position;
3) Add a event listener on your viewport for FlexEvent.UpdateComplete and set the scroll position to the variable stored.
In a nutshell, what we are doing is to have the scroll position stored in variable every time user interacts with it and when our viewport is updated (due to dataprovider change) we just set the scroll position we have stored previously in the variable.
I have faced this problem before and solved it by using a data proxy pattern with a matcher. Write a matcher for your collection that supports your list by updating only changed objects and by updating only attributes for existing objects. The goal is to avoid creation of new objects when your data source refreshes.
When you have new data for the list (after a refresh), loop through your list of new data objects, copying attributes from these objects into the objects in the collection supporting your list. Typically you will match the objects based on id. Any objects in the new list that did not exist in the old one get added. Your scroll position will normally not change and any selections are usually kept.
Here is an example.
for each(newObject:Object in newArrayValues){
var found:Boolean = false;
for each(oldObject:Object in oldArrayValues){
if(oldObject.id == newObject.id){
found = true;
oldObject.myAttribute = newObject.myAttribute;
oldObject.myAttribute2 = newObject.myAttribute2;
}
}
if(!found){
oldArrayValues.addItem(newObject);
}
}
My solution for this problem was targeting a specific situation, but it has the advantage of being very simple so perhaps you can draw something that fits your needs from it. Since I don't know exactly what issue you're trying to solve I'll give you a description of mine:
I had a List that was progressively loading data from the server. When the user scrolled down and the next batch of items would be added to the dataprovider, the scrollposition would jump back to the start.
The solution for this was as simple as stopping the propagation of the COLLECTION_CHANGE event so that the List wouldn't catch it.
myDataProvider.addEventListener(
CollectionEvent.COLLECTION_CHANGE, preventRefresh
);
private function preventRefresh(event:CollectionEvent):void {
event.stopImmediatePropagation();
}
You have to know that this effectively prevents a redraw of the List component, hence any added items would not be shown. This was not an issue for me since the items would be added at the end of the List (outside the viewport) and when the user would scroll, the List would automatically be redrawn and the new items would be displayed. Perhaps in your situation you can force the redraw if need be.
When all items had been loaded I could then remove the event listener and return to the normal behavior of the List component.
This problem has bugged me for several years and maybe someone here knows a simple solution, since I just ran into it again.
QUESTION: Is there any way to get the XtraGrid to "forget" the current focused row index before a new (different) datasource is assigned to the grid?
BACKGROUND
We use the XtraGrid as a kind of controller for what is displayed in another panel of a multipane Winform.
Now imagine a hypothetical scenario where the datasource of the XtraGrid keeps changing according to menu selections. Menu item 1 populates the grid with a list of today's entrees in the cafeteria: Id, Name. Menu item 2 populates the grid with a list of Customers the user must phone that day: ID, Name. Important thing is that these are separate distinct datasources, and the grid's datasource is being assigned and reassigned.
CRITICAL FACT FOR THIS QUESTION:
We want the grid's FocusedRowChanged event to be the single place where we trap the user's selection in the controller grid. We are a "no spaghetti code" shop. FocusedRowChanged is better than a click event because it handles keyboard navigation too. The row with the focus contains the ID of the detail record we need to fetch from the database for display in Panel #2. This works--most of the time.
Here's how it doesn't work: let's say that on a given day, the list of customers the user must contact contains only one row. So the first (and only) row in the grid is the focused row. Now let's say that the user goes up to the menu and selects the menu item to display the day's cafeteria entrees. When the user clicks on the first item in the Entrees list, the FocusedRowChanged event does NOT fire because the grid has retained a memory of the focused row index from the previous datasource. The focused row index has not changed. And thus the user's selection doesn't trigger anything.
I tried to get DevExpress to offer a second more row-object-oriented mode (as distinct from row-index-oriented approach) whereby each row in the grid would have a GUID, and the FocusedRowChanged event would fire whenever the GUID of the currently focused row differed from the GUID of the previously focused row, regardless of whether the focused row index happened to be the same. This would allow dynamic changes of datasource and enable the desired behavior. But they demurred.
So I'll ask my question again, Is there any way to get the XtraGrid to "forget" the current focused row index before a new datasource is assigned to the grid?
Tim, I had the exact same problem when the grid only had one row of data in it and then changed data sources. I solved it by setting the gridview.FocusedRowHandle = -1 after setting the new datasource.
In a similar situation, I am subscribing to the
FocusedRowObjectChanged
event (using DevExpress 16.1).
I think that the best solution to this problem is to create a new GridView object and override its DoChangeFocusedRowInternal method. Below you will find the default implementation of this method. All you need to do is to change the marked row just as your needs dictate. Also, take a look at the How to create a GridView descendant class and register it for design-time use article, it contains some useful information.
public class MyGridView : GridView {
protected override void DoChangeFocusedRowInternal(int newRowHandle, bool updateCurrentRow) {
if(this.lockFocusedRowChange != 0) return;
if(!IsValidRowHandle(newRowHandle))
newRowHandle = DevExpress.Data.DataController.InvalidRow;
if(FocusedRowHandle == newRowHandle) return; // <<<<<<
int currentRowHandle = FocusedRowHandle;
BeginLockFocusedRowChange();
try {
DoChangeFocusedRow(FocusedRowHandle, newRowHandle, updateCurrentRow);
}
finally {
EndLockFocusedRowChange();
}
RaiseFocusedRowChanged(currentRowHandle, newRowHandle);
}
}
UPDATE
My code:
namespace MyXtraGrid {
public class MyGridControl : GridControl {
protected override BaseView CreateDefaultView() {
return CreateView("MyGridView");
}
protected override void RegisterAvailableViewsCore(InfoCollection collection) {
base.RegisterAvailableViewsCore(collection);
collection.Add(new MyGridViewInfoRegistrator());
}
}
public class MyGridViewInfoRegistrator : GridInfoRegistrator {
public override string ViewName { get { return "MyGridView"; } }
public override BaseView CreateView(GridControl grid) {
return new MyGridView(grid as GridControl);
}
}
public class MyGridView : GridView {
public MyGridView(GridControl ownerGrid) : base(ownerGrid) { }
public MyGridView() { }
protected virtual bool RowEqual(int focusedRowHandle, int newRowHandle) {
if(IsDesignMode)
return focusedRowHandle == newRowHandle;
DataRow row1 = GetDataRow(focusedRowHandle);
DataRow row2 = GetDataRow(newRowHandle);
return row1 == row2;
}
protected override void DoChangeFocusedRowInternal(int newRowHandle, bool updateCurrentRow) {
if(this.lockFocusedRowChange != 0) return;
if(!IsValidRowHandle(newRowHandle))
newRowHandle = DevExpress.Data.DataController.InvalidRow;
if(RowEqual(FocusedRowHandle, newRowHandle))
return;
int currentRowHandle = FocusedRowHandle;
BeginLockFocusedRowChange();
try {
DoChangeFocusedRow(FocusedRowHandle, newRowHandle, updateCurrentRow);
}
finally {
EndLockFocusedRowChange();
}
RaiseFocusedRowChanged(currentRowHandle, newRowHandle);
}
}
}
You can subscribe on the DataSourceChanged event which will fire when Data source changes (you guessed it!) so then you can get using GetFocusedObject() the object and display the relevant items for the other grid...
Does anyone know how to programmatically expand the nodes of an AdvancedDataGrid tree column in Flex? If I was using a tree I would use something like this:
dataGrid.expandItem(treeNodeObject, true);
But I don't seem to have access to this property in the AdvancedDataGrid.
AdvancedDataGrid has an expandItem() method too:
http://livedocs.adobe.com/flex/3/langref/mx/controls/AdvancedDataGrid.html#expandItem()
Copy the sample found at the aforementioned url and call this function:
private function openMe():void
{
var obj:Object = gc.getRoot();
var temp:Object = ListCollectionView(obj).getItemAt(0);
myADG.expandItem(temp,true);
}
You could also open nodes by iterating through the dataProvider using a cursor. Here is how I open all nodes at a specified level:
private var dataCursor:IHierarchicalCollectionViewCursor;
override public function set dataProvider(value:Object):void
{
super.dataProvider = value;
/* The dataProvider property has not been updated at this point, so call
commitProperties() so that the HierarchicalData value is available. */
super.commitProperties();
if (dataProvider is HierarchicalCollectionView)
dataCursor = dataProvider.createCursor();
}
public function setOpenNodes(numLevels:int = 1):void
{
dataCursor.seek(CursorBookmark.FIRST);
while (!dataCursor.afterLast)
{
if (dataCursor.currentDepth < numLevels)
dataProvider.openNode(dataCursor.current);
else
dataProvider.closeNode(dataCursor.current);
dataCursor.moveNext();
}
dataCursor.seek(CursorBookmark.FIRST, verticalScrollPosition);
// Refresh the data provider to properly display the newly opened nodes
dataProvider.refresh();
}
Would like to add here that the AdvancedDataGrid, in spite of having an expandAll() method, has a property called displayItemsExpanded, which set to true will expand all the nodes.
For expanding particular children, the expandChildrenOf() and expandItem() methods can be used, as can be verified from the links given above.