We Keep Coding

What parent to set when calling FieldEditor#setEnabled?

I am building a preference page in Eclipse by extending the FieldEditorPreferencePage class. this page contains 2 fields : 1 BooleanFieldEditor (checkbox) and 1 FileFieldEditor. I would like to disable/enable the file field following the checkbox value.
I went up to something like this (some obvious code is not displayed):
public class PreferencePage extends FieldEditorPreferencePage implements IWorkbenchPreferencePage {
public static final String PREF_KEY_1 = "checkBoxPref";
public static final String PREF_KEY_2 = "filePref";
private FileFieldEditor pathField;
private BooleanFieldEditor yesOrNoField;
private Composite pathFieldParent;
#Override
protected void createFieldEditors() {
this.yesOrNoField = new BooleanFieldEditor(PREF_KEY_1, "Check this box!", getFieldEditorParent());
this.pathFieldParent = getFieldEditorParent();
this.pathField = new FileFieldEditor(PREF_KEY_2, "Path:", this.pathFieldParent);
addField(this.yesOrNoField);
addField(this.pathField);
boolean isChecked = getPreferenceStore().getBoolean(PREF_KEY_1);
updatePathFieldEnablement(! isChecked);
}
/**
* Updates the fields according to entered values
*/
private void updatePathFieldEnablement(boolean enabled) {
this.pathField.setEnabled(enabled, this.pathFieldParent);
}
#SuppressWarnings("boxing")
#Override
public void propertyChange(PropertyChangeEvent event) {
if (event.getProperty().equals(FieldEditor.VALUE) && event.getSource() == this.yesOrNoField) {
updatePathFieldEnablement(! (boolean) event.getNewValue());
}
super.propertyChange(event);
}
}
My question is about this second parameter in FieldEditor#setEnabled. This parameter is the parent composite of the FieldEditor's controls ("Used to create the controls if required" says the javadoc) . At first, I set the value with the return of getFieldEditorParent but then I got an exception "Different parent". So I ended storing it (cf. this.pathFieldParent) and give it back to setEnabled and it works (or it seems to work).
But I am not sure I am doing well, especially because I had to create a member in my class that means nothing to it (and I would have to create many of them if I had many fields to enable/disable).
Do you think I am doing well or is there a better way to provide this parent ? And could you explain to me why *setEnabled" needs it ?
Thanks.

You are using the default FLAT layout for the preference page. When this layout is used each call to getFieldEditorParent generates a new Composite so you have to make just one call and remember the correct parent. Using the GRID layout getFieldEditorParent always returns the same parent. This is the actual code:
protected Composite getFieldEditorParent() {
if (style == FLAT) {
// Create a new parent for each field editor
Composite parent = new Composite(fieldEditorParent, SWT.NULL);
parent.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
return parent;
}
// Just return the parent
return fieldEditorParent;
}
setEnabled does sometimes create a new Label control so it needs to know the correct parent Composite.

SWT , TreeViewer , CellEditor with ComboBox

While using EditingSupport for a treeColumn in a TreeViewer, Is there any way i can just reflect the Changes in the View instead of changing the model and then using getViewer().update(element,null);
Detail:
I want to achieve the following functionality:
Show a tree View with |Object| (ComboBox)property|
Upon selection and clicking on the button i want to show user the summary of changes and then upon clicking confirm i want to apply those changes to the model (Object)
I am using a TreeViewer, Within that i have a column with EditingSupport Enabled.
Whenever I select a value from the ComboBox and click somewhere else (lostFocus kind of ) the Value sets to default.
I have figured out that after SetValue() is called the TreeLabelProvider is again called(using debug points)
Is there any way i can just reflect the Changes in the View instead of changing the model and using getViewer().update(element,null);
Some FYIs :
Package Object contains multiple versions
ContentProvider does the job to fetch the object
LabelProvider gets all the Versions from the package(String[]) and shows the first one.
//Code to Create the UI
// blah
TreeViewerColumn column2 = new TreeViewerColumn(treeViewer, SWT.LEFT);
column2.getColumn().setText("Version");
column2.getColumn().setWidth(130);
treeViewer.setLabelProvider(new PackageUpdateTreeLabelProvider());
EditingSupport exampleEditingSupport = new OperationEditingSupport(
column2.getViewer());
column2.setEditingSupport(exampleEditingSupport);
OperationEditingSupport Class
private class OperationEditingSupport extends EditingSupport {
private ComboBoxCellEditor cellEditor = null;
private OperationEditingSupport(ColumnViewer viewer) {
super(viewer);
cellEditor = new ComboBoxCellEditor(
((TreeViewer) viewer).getTree(), new String[] {},
SWT.READ_ONLY);
}
#Override
protected CellEditor getCellEditor(Object element) {
// TODO Auto-generated method stub
if (element instanceof IPackageInfo) {
IPackageInfo pkg = (IPackageInfo) element;
cellEditor.setItems(PackageMgrUtil.getInstance().getVersions(
(IdmPackage) pkg, false, true));
return cellEditor;
}
return null;
}
#Override
protected boolean canEdit(Object element) {
return true;
}
#Override
protected Object getValue(Object element) {
// TODO Auto-generated method stub
return 0;
}
#Override
protected void setValue(Object element, Object value) {
/* only set new value if it differs from old one */
}
}
***************************************************
When i click on the cell of column2 i get the combo box but when i select something and move the focus somewhere else.It again shows the default Value
on debuging i found that :
it agains calls the label Provider which fetches all the Version of the package and then shows the first one hence I can not see any change.
what i want is that it should keep the selection intact without changing the underlying object.
thanks for the help.

Figured it out.
following code added to the SetValue() method solves it.
m_tree = (Tree)getViewer.getControl();
TreeItem[] ti = m_tree.getSelection();
CCombo c = ((CCombo)cellEditor.getControl());
String str = c.getItem(c.getSelectionIndex());
ti[0].setText(1, str );

Updating a Wicket WebMarkupContainer

Inside my Wicket webpage, I have a WebMarkupContainer which contains a ListView:
notifications = new ArrayList<Notification>(...);
ListView listView = new ListView("notification", notifications) {
#Override
protected void populateItem(ListItem item) {
...
}
};
container = new WebMarkupContainer("container");
container.setOutputMarkupId(true);
container.add(listView);
this.add(container);
The WebMarkupContainer is in place in order to let me dynamically update the list of items shown to the user onscreen. This is possible when the user clicks on a link or by adding the container to incoming AjaxRequestTarget.
Now I'm required to update the list without having an Ajax request:
public void refresh() {
List<Notification> newNotifications = ...
notifications.addAll(0, newNotifications);
}
This method is called in a run-time environment and the list of notifications, which is a private field of my webpage (same one as last code), will contain new objects. I want these new items displayed to the user. Is it possible to update (or re-render) the container?
I'm new to Wicket so if you have a better way to achieve the same results, I would appreciate if you could share it with me.

You would have to do it on a timer. Use AjaxSelfUpdatingTimerBehavior to do so. Just set some sensible duration and add your container to target in 'onTimer()' method.
EDIT:
If your 'refresh()' function is only called when new notifications appear, you could set a flag on your page (define boolean variable on page and change it to true when new notification appears and to false once listView is refreshed). Then you can set short duration on the behavior and 'onTimer()' would look something like that:
onTimer(AjaxRequestTarget target) {
if(newNotifications) {
target.add(container);
newNotifications = false;
}
}
And refresh
public void refresh() {
List<Notification> newNotifications = ...
notifications.addAll(0, newNotifications);
newNotifiactions = true;
}
That way container won't be refreshed too often (which might cause strange effects) and will refresh every time new notification appears.

How to set EditTextBox into edit mode by program code?

I'm using GWT with a EditTextCell, which goes into edit mode on click.
Does anybody know a way of forcing the box into edit mode by program code?
Would I have to somehow fire a ClickEvent onto that box? Or how could this be done?

You can add the following method to your CellTable or DataGrid:
public void focus(final int row, final int column) {
Scheduler.get().scheduleDeferred(new ScheduledCommand() {
#Override
public void execute() {
getRowElement(row).getCells().getItem(column).getFirstChildElement().getFirstChildElement().focus();
}
});
}
Then you can simple call .focus(row, column) when you need to set focus on a given cell.
Or you can call .getRowElement()... directly, but I recommend wrapping it in a ScheduledCommand so it does not fire too early - before the cell is ready to accept focus.

It turned out I can fire a native click event on my cell as follows:
NativeEvent nativeevent = Document.get().createClickEvent(1, 0, 0, 0, 0, false, false, false, false);
cell.getElement().dispatchEvent(nativeevent);

You can also write render event or can add clickHandler for setting the contentEditable=true or false.
private class CustomEditCell extends EditTextCell {
public void render(com.google.gwt.cell.client.Cell.Context context, String value, SafeHtmlBuilder sb) {
sb.appendHtmlConstant("<div contentEditable='true' unselectable='true' >"+value+"</div>");
}
}

How can I replace a div with a widget when it is already contained in another widget?

I'm using Ext-GWT and I think ListView is the right layout for what I need. My problem is that I have to use a HTML template for all of my items, but I want to build GWT/Ext-GWT widgets instead, so I'm using div placeholders that I will replace with the proper widgets.
How can I replace my div with a widget? My first attempt was to use RootPanel.get('div-id'), but apparently you can't create a RootPanel that is in a widget (I used debug mode to step through the code till I found that silent exception).
public class TicketContainer extends LayoutContainer {
private ArrayList<BasicTicket> tickets;
public TicketContainer(ArrayList<BasicTicket> tickets) {
this.tickets = tickets;
}
#Override
protected void onRender(Element parent, int index) {
super.onRender(parent, index);
setLayout(new FlowLayout(1));
ListStore<BasicTicket> store = new ListStore<BasicTicket>();
store.add(this.tickets);
ListView<BasicTicket> view = new ListView<BasicTicket>(store);
view.addListener(Events.Refresh, new Listener<BaseEvent>() {
#Override
public void handleEvent(BaseEvent be) {
for (BasicTicket ticket : tickets) {
// At this point I need to find the div with the id
// "ticket_"+ticket.getId() and replace it with a GWT
// widget that I can add events to and enable drag and drop
}
}
});
add(view);
}
private native String getTemplate() /*-{
return ['<tpl for=".">',
'<div id="ticket_{id}"></div>',
'</tpl>'].join("");
}-*/;
}
The full source is at https://code.launchpad.net/~asa-ayers/+junk/Kanban if you need additional context in the code.

In "pure" GWT, the answer would be to use HTMLPanel:
String id = DOM.createUniqueId();
HTMLPanel panel = new HTMLPanel("<div class=\"content\" id=\"" + id + "\"></div>");
panel.add(new Label("Something cool"), id);
As you can see, the com.google.gwt.user.client.ui.HTMLPanel.add(Widget, String) takes the id of an element withing the HTMLPanel and places the Widget inside that element.
I haven't used Ext-GWT, but you can either use HTMLPanel or search for an exquivalent in Ext-GWT.

You can also wrap an existing div in an HTML Panel.
HTMLPanel newPanel = HTMLPanel.wrap(Document.get().getElementById("yourDivId"));
newPanel.add(your_widget);