What is the right usage for the SingleSelectionModel? - gwt

we would like to link from a CellTable to a property editor page. We use the SingleSelectionModel to get notified, when a user clicks on an item.
It is initialized like this:
private final SingleSelectionModel<Device> selectionModel = new SingleSelectionModel<Device>();
We then assign the selection change handler:
selectionModel.addSelectionChangeHandler(this);
Our selection change handler looks like this:
#Override
public void onSelectionChange(SelectionChangeEvent event) {
Log.debug("DevicesPresenter: SelectionChangeEvent caught.");
Device selectedDevice = selectionModel.getSelectedObject();
if (selectedDevice != null) {
selectionModel.clear();
if (selectionModel.getSelectedObject() != null){
Log.debug("DevicesPresenter: selected item is " + selectionModel.getSelectedObject());
}
else{
Log.debug("DevicesPresenter: selected item is null");
}
deviceEditorDialog.setCurrentDevice(selectedDevice.getUuid());
// get the container data for this device
clientModelProvider.fetchContainersForDevice(selectedDevice.getUuid());
PlaceRequest request = new PlaceRequest.Builder()
.nameToken(NameTokens.deviceInfo)
.with("uuid", selectedDevice.getUuid())
.build();
Log.debug("Navigating to " + request.toString());
placeManager.revealPlace(request);
}
}
Now there are two issues: There always seem to be two SelectionChangeEvents at once and i really cannot see why. The other thing is: How is the right way do handle selection of items and the related clearing of the selection model? Do we do that the right way?
Thanks!

If you only want to get notified of "clicks" without keeping the "clicked" item selected, use a NoSelectionModel instead; no need to clear the selection model as soon as something is selected.
As for your other issue with being called twice, double-check that you haven't added your selection handler twice (if you can unit-test your DevicesPresenter, introspect the handlers inside the selection model for example)

In your line selectionModel.addSelectionChangeHandler(this); what does this refer?
Here my code how I use SingleSelectionModel
public class MyClass{
private final SingleSelectionModel<CountryDto> selectionModel = new SingleSelectionModel<CountryDto>();
...
public MyClass(){
cellTable.setSelectionModel(selectionModel);
selectionModel.addSelectionChangeHandler(new SelectionChangeEvent.Handler() {
#Override
public void onSelectionChange(SelectionChangeEvent event) {
CountryDto selected = selectionModel
.getSelectedObject();
if (selected != null) {
Window.alert("Selected country "+selected.getTitle());
}
}
});
}
}

Related

Swap the type of link depending on model object

I'm at complete loss how to proceed further:
I have panel with a DropDownChoice and a submit button next to it. Depending on the selected value of the DropDownChoice (Obtained upon the firing of a OnChangeAjaxBehavior attached to it, the submit button needs to either replace the whole panel with a different one, OR become an ExternalLink.
Currently, the code looks like that:
public class ReportSelectionPanel extends Panel {
protected OptionItem selectedOption ;
public ReportSelectionPanel(String id) {
super(id);
IModel<List<OptionItem>> choices = new AbstractReadOnlyModel() {
// Create a list of options to be displayed in the DropDownChoice
} ;
final IModel<OptionItem> optionModel =
new PropertyModel<OptionItem>(this,"selectedOption") ;
final DropDownChoice<OptionItem> options =
new DropDownChoice("selectChoice",optionModel,choices) ;
// I don't know what the button should be... Plain Button? A Link?
final Component button = ???
options.add( new OnChangeAjaxBehavior() {
protected void onUpdate(AjaxRequestTarget target) {
if ( selectedOption.getChild() == null ) {
// button becomes an ExternalLink.
// A new window will popup once button is clicked
} else {
// button becomes a Something, and upon clicking,
// this ReportSelectionPanel instance gets replaced by
// an new Panel instance, the type of which is
// selectedOption.getChild()
}
} ) ;
I'm really not quite sure what the commented lines should become to achieve the result. Any suggestions?
Thanks!
Eric
IMHO it's nicer to keep just one button and just react differently depending on the selected option:
final Component button = new AjaxButton("button") {
public void onClick(AjaxRequestTarget target) {
if (selectedOption.getChild() == null) {
PopupSettings popup = new PopupSettings();
popup.setTarget("'" + externalUrl + "'");
target.appendJavascript(popup.getPopupJavaScript());
} else {
ReportSelectionPanel.this.replaceWith(new ReportResultPanel("..."));
}
}
};
// not needed if options and button are inside a form
// options.add( new OnChangeAjaxBehavior() { } ) ;

checkbox not getting unchecked in wicket

I have a checkgroup and on selecting a checkbox in the group I want to get the number of selected/checked check boxes.
By the below code, I am able to get the selected number of checkboxes but on unchecking or removing the selection, i see that its still selected.
Example : I have selected 2 now I get 2 string selected.
Now I unselect one checkbox, even now i get 2 strings selected. While I expect one string to be checked.
The code is given below:
final CheckGroup myGroup = new CheckGroup("group", new ArrayList()) {
#Override
protected Collection<String> convertValue(String[] values) throws ConversionException {
Collection<String> myCollection = super.convertValue(values);
checkedString.addAll(myCollection);
HashMap<Integer, String> myTempList = new HashMap<Integer, String>();
for (String myString : checkedString) {
myTempList.put(myString.getSystemId(), myString);
}
checkedString.clear();
for (Entry<Integer, String> myEntry : myTempList.entrySet()) {
checkedString.add(myEntry.getValue());
}
return checkedString;
}
#Override
protected void onSelectionChanged(Collection newSelection) {
newSelection = checkedString;
}
#Override
protected boolean wantOnSelectionChangedNotifications() {
return true;
}
};
add(myForm);
myForm.add(myGroup);
Add a behavior to your component
sampleChckbox.add(new AjaxFormComponentUpdatingBehavior("onclick"){
#Override
protected void onUpdate(AjaxRequestTarget target) {
//perform your operation here
}
This method will fire an Ajax request on "onClick" event; which will update your backend logic at runtime
edit :
To be very specific to CheckGroup class use the AjaxFormChoiceComponentUpdatingBehavior
AjaxFormChoiceComponentUpdatingBehavior is the behavior to use with CheckGroups and RadioGroups. If you used an AjaxFormComponentUpdatingBehavior with the onchange event, you'd run into this bug with IE
. AjaxFormChoiceComponentUpdatingBehavior handles this properly, adding onclick event handlers to each of the Checks in the CheckGroup.
As a side note, what Igor stated in that mail, is that CheckBox can be replaced with AjaxCheckBox, not Check. AjaxCheckBox is nothing more than a convenience subclass of CheckBox with an AjaxFormComponentUpdatingBehavior("onclick"), as the sources show.

Access row data in DoubleCLickListener of TableViewer

I need to show some information related to the row or cell being clicked in table of TableViewer.
As far as I understand I can use (TableViewer) event.getViewer() in viewer.addDoubleClickListener() to retrieve data of current row or cell being clicked. Correct me if I am wrong.
But my run() function is in private void makeActions() where I can't access event. How can I overcome this problem?
private void hookDoubleClickAction()
{
viewer.addDoubleClickListener(new IDoubleClickListener()
{
public void doubleClick(DoubleClickEvent event)
{
//TableViewer chek = (TableViewer) event.getViewer();
doubleClickAction.run();
}
});
}
private void makeActions()
{
doubleClickAction = new Action()
{
public void run()
{
}
}
}
Keep a reference to the TableViewer as a field in your main class (or pass it as a parameter to the action constructor). You can then get the current selection from the viewer in your action using:
IStructuredSelection selection = (IStructuredSelection)viewer.getSelection();

How can I observe the changed state of model items in an ObservableList?

I have an ObservableList of model items. The model item is enabled for property binding (the setter fires a property changed event). The list is the content provider to a TableViewer which allows cell editing. I also intend to add a way of adding new rows (model items) via the TableViewer so the number of items in the list may vary with time.
So far, so good.
As this is all within an eclipse editor, I would like to know when the model gets changed. I just need one changed event from any changed model item in order to set the editor 'dirty'. I guess I could attach some kind of listener to each individual list item object but I wonder if there is a clever way to do it.
I think that I might have a solution. The following class is an inline Text editor. Changes to the model bean (all instances) are picked up using the listener added in doCreateElementObservable. My eclipse editor just needs to add its' own change listener to be kept informed.
public class InlineEditingSupport extends ObservableValueEditingSupport
{
private CellEditor cellEditor;
private String property;
private DataBindingContext dbc;
IChangeListener changeListener = new IChangeListener()
{
#Override
public void handleChange(ChangeEvent event)
{
for (ITableEditorChangeListener listener : listenersChange)
{
listener.changed();
}
}
};
public InlineEditingSupport(ColumnViewer viewer, DataBindingContext dbc, String property)
{
super(viewer, dbc);
cellEditor = new TextCellEditor((Composite) viewer.getControl());
this.property = property;
this.dbc = dbc;
}
protected CellEditor getCellEditor(Object element)
{
return cellEditor;
}
#Override
protected IObservableValue doCreateCellEditorObservable(CellEditor cellEditor)
{
return SWTObservables.observeText(cellEditor.getControl(), SWT.Modify);
}
#Override
protected IObservableValue doCreateElementObservable(Object element, ViewerCell cell)
{
IObservableValue value = BeansObservables.observeValue(element, property);
value.addChangeListener(changeListener); // ADD THIS LINE TO GET CHANGE EVENTS
return value;
}
private List<ITableEditorChangeListener> listenersChange = new ArrayList<ITableEditorChangeListener>();
public void addChangeListener(ITableEditorChangeListener listener)
{
listenersChange.remove(listener);
listenersChange.add(listener);
}
public void removeChangeListener(ITableEditorChangeListener listener)
{
listenersChange.remove(listener);
}
}

GWT CellTable SelectionModel can not deselect item after editing

Hello I have a Contact class with informations which i show in a CellTable.
The CellTable has a DataListProvider, MultiSelectionModel and KeyProvider
which checks the id of the Contact.
DataListProvider and CellTable have the same KeyProvider.
if i only select/deselect the items in the CellTable and show them in a TextBox ists working fine. But the when i change the value of the Contact item in the TextBox(Contact instance) and try to deselect the item the selectionmodel says its still selected?
I tried with clear() but its still selected!
GWT 2.5 / FireFox
ProvidesKey<Contact> keyProvider = new ProvidesKey<Contact>(){
#Override
public Object getKey(Contact item) {
return item.getIdContact();
}
};
public MyCellTable(boolean canLoad, Integer pagesize, ProvidesKey<T> keyProvider) {
super(-1, resource, keyProvider);
selectionModel = new MultiSelectionModel<T>();
selectionModel .addSelectionChangeHandler(new SelectionChangeEvent.Handler() {
#Override
public void onSelectionChange(SelectionChangeEvent event) {
selectionChange();
}
});
dataProvider = new ListDataProvider<T>(keyProvider);
dataProvider.addDataDisplay(this);
}
in the selection event i call
protected void selectionChange(){
Contact c = grid.getGrid().getSelectedItem();
if(c != null){
cpForm.enable();
cpForm.clear();
form.bind(c); // Formular which updates the selected instance
cpForm.add(form);
}else{
cpForm.disable(noseletionText);
}
}
i have no ValueUpdater
when i select an item i generate a formular and if i change something i call:
#Override
public void save() {
super.save();
ContactServiceStore.get().updateContact(manager.getBean(),
new MyAsyncCallback<Void>() {
#Override
public void onSuccess(Void result) {
onchange();
}
});
}
i if call the method without changes on the contact its still working and i can deselect but when i change the name or something else i cant select other items or deselect the current item!
You're not actually using your ProvidesKeys in your MultiSelectionModel. You need to create your MultiSelectionModel like so:
MultiSelectionModel<T> selectionModel = new MultiSelectionModel<T>(keyProvider);
If you don't supply the MultiSelectionModel with a ProvidesKey it will use the actual object as a key.
Make sure you also add the MultiSelectionModel to the table:
cellTable.setSelectionModel(selectionModel);
The reason selectionModel.clear() wasn't working was because selectionModel was not set to the table.