I'm currently recoding a TableViewer to work fully virtual. So far I'm pretty content with the results, but I still have a problem, that all visible elements in the table are refreshed on a fixed timer. The model changes continously though. This means, that if I click on an entry before a periodic update happens, the table loads in the actual value for that position, but leaves all other elements untouched. Since this is how the LazyContentProvider works that is set for the TableViewer this is not much of a problem.
Since my TableViewer is a Live-Viewer of incoming events, with the newest entry shifting all other items one down, I'd like to refresh all visible elements on adding a new event.
I've tried to use TableViewer.refresh() on adding a new item, but that does not seem to do anything.
Since the full code is pretty complex, and part of a bigger piece of code I'll provide a basic representation of the code:
public class MyClass{
public TableViewer liveViewer;
public List<String> myItems=new ArrayList<>();
void init(){
liveViewer = new TableViewer(liveComp, SWT.BORDER | SWT.FULL_SELECTION | SWT.VIRTUAL);
liveViewer.setContentProvider(new LiveViewerContentProvider(liveViewer));
liveViewer.setLabelProvider(someLabelProvider);
liveViewer.setUseHashlookup(true);
ClassThatProvidesItems.addListener(new ItemAddedListener(){
#Override
void itemAdded(String item){
myItems.add(0,item);
}
}
}
}
public class LiveViewerContentProvider implements ILazyContentProvider{
private TableViewer viewer;
private List<String> input;
public LiveViewerContentProvider(TableViewer viewer) {
this.viewer = viewer;
}
#Override
public void dispose() {
}
#Override
public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
this.input = (List<String>) newInput;
}
#Override
public void updateElement(int index) {
viewer.replace(input.get(index), index);
}
}
I'm aware, that an ArrayList is probably not the best choice, for always adding an element at the head, but please ignore it for now. I've tried to perform a liveViewer.refresh(); at the end of the listener callback, but it didn't seem to refresh my elements. What could I do to force a refresh for all visible items on adding a new one?
Thanks in advance.
I've just noticed, that my solution was almost working. The problem was, that the whole code was somewhere within a weird try-catch-block that just silently swallowed Exceptions, and didn't give me the invalid-Thread-access exception that I should have gotten for not performing the liveViewer.refresh within the Display-Thread. Wrapping the line like this fixed the issue:
Display.getDefault().asyncExec(new Runnable() {
#Override
public void run() {
liveViewer.refresh();
}
});
Related
I'm currently writing a small tool for sending sql queries to a database and recieving the according data.
Now to my problem:
I want to allow the user to enter a new search query or select from a "latest" list, where the last few queries are saved.
For that, I planned on using an editable JComboBox, but I'm having trouble diplaying multiple lines of text in the box itself.
The reason I want to do that, is because sql queries can get quite long and since I want make the box editable and at the same time keep the frame clean.
I've found ways to display multiple lines in the dropdown menu, but nothing for the box itself.
Thank you in advance and please forgive me if I overlooked something simple ;)
Greetings
Zeus
Extended editing functionality is supplied by the ComboBoxEditor, this allows you to define the actual component which is used as the combobox's editor
Based on your requirements, you're going to need (at the very least) a JTextArea, to provide (optionally) word wrapping and multiple lines
A rough and ready example might look something like this...
public class TextAreaComboBoxEditor implements ComboBoxEditor {
private JTextArea ta = new JTextArea(4, 20);
private JScrollPane sp = new JScrollPane(ta);
public TextAreaComboBoxEditor() {
ta.setWrapStyleWord(true);
ta.setLineWrap(true);
}
#Override
public Component getEditorComponent() {
return sp;
}
#Override
public void setItem(Object anObject) {
if (anObject instanceof String) {
ta.setText((String) anObject);
} else {
ta.setText(null);
}
}
#Override
public Object getItem() {
return ta.getText();
}
#Override
public void selectAll() {
ta.selectAll();
}
#Override
public void addActionListener(ActionListener l) {
}
#Override
public void removeActionListener(ActionListener l) {
}
}
This doesn't support ActionListener, as JTextArea uses the Enter key for it's own purposes. If you wanted to, you could use the key bindings API to add your own Action that can trigger the ActionListeners, for that, you'd need to supply a List or other means for managing them so you can call them back
I have this behavior added to a component(MarkupContainer)
AjaxSelfUpdatingTimerBehavior updateBehavior = new AjaxSelfUpdatingTimerBehavior(Duration.seconds(3))
{
#Override
public void onEvent(Component component, IEvent<?> event) {
// some business logic
}
};
Somewhere , on the same page I have an AjaxLink which redirects to another page(in whom constructor I pass the actual page as a parameter) and on that page I have a "Back" AjaxLink which redirects me back , calling setResponsePage(myFirstPage) .
The problem is that even though , when rendering the page the behavior updates once , it stops updating once at 3 seconds , as was constructed for.No problem faced with the behavior until leaving the page.
Probably not the best solution , but I managed to fix it by removing the behavior onBeforeRender() of the page and adding again . I declared a field on the page private int autoUpdateBehaviorId = -1;
public void addUpdateBehavior(Component c)
{
if(autoUpdateBehaviorId >= 0)
c.remove(c.getBehaviorById(autoUpdateBehaviorId));
AjaxSelfUpdatingTimerBehavior updateBehavior = new AjaxSelfUpdatingTimerBehavior(Duration.seconds(3))
{
#Override
public void onEvent(Component component, IEvent<?> event) {
// bussines logic
}
};
c.add(updateBehavior);
autoUpdateBehaviorId = c.getBehaviorId(updateBehavior);
}
#Override
protected void onBeforeRender() {
super.onBeforeRender();
addUpdateBehavior(myContainer);
}
Not necessarily the solution to your problem; but I have implemented the behavior by overriding onConfigure method of the AjaxSelfUpdatingTimerBehavior as below.
In my case, I had to update label with a count of current records in queue every 10 seconds.
Following is code snippet:
labelToBeUpdated.add(new AjaxSelfUpdatingTimerBehavior(Duration.seconds(configurableDelay)) {
#Override
public void onConfigure(Component component) {
String inProgressOutOfTotal = "10/100"; //Business logic to get total count and inprogress count
labelToBeUpdated.setDefaultModel(Model.of(inProgressOutOfTotal));
//Set visibility of the component if needed
}
}
labelToBeUpdated.setOutputMarkupId(true);
Just curious; is it that onEvent is waiting on an event on the component in order to refresh? Since onConfigure is called before the rendering cycle has begun, it is working for me.
But as Sven Meier has mentioned, you might still want to work on his advise to get your code with onEvent.
I am stuck in getting an absolute position of DialogBox. I know it is the common problem (and strange workaround) for PopupPanel (which is parent to DialogBox) to set it, but what if I want to get it, what is the exact moment when the box attached to DOM? Neither overriding show nor onAttach nor show does not help:
class MyDialog extends DialogBox {
public MyDialog(. . .) {
ComplexPanel vert = new VerticalPanel();
vert.add("Test");
vert.add(new Button("Close", new ClickHandler() {
#Override
public void onClick(ClickEvent event) {
MyDialog.this.hide();
}
}));
setWidget(vert);
this.addAttachHandler(new AttachEvent.Handler() {
#Override
public void onAttachOrDetach(AttachEvent event) {
if (event.isAttached()) Log.debug("attach:"+MyDialog.this.getAbsoluteLeft() +";"+
MyDialog.this.getAbsoluteTop());
}
});
}
#Override
protected void onLoad() {
super.onLoad();
Log.debug("load:"+this.getAbsoluteLeft() +";"+this.getAbsoluteTop());
}
#Override
public void show() {
super.show();
Log.debug("show:"+this.getAbsoluteLeft() +";"+this.getAbsoluteTop());
}
}
So when I call new MyDialog().show();, all this lines do log 0;0, however dialog is positioned in center of a page. But what I want is the sum of the chain of offsetParent positions. (And they are 0 in these moments even in JavaScript, if use JSNI to check this)
Again, setPopupPositionAndShow allows to set position but not get it :(
Finally, I've got this to work:
#Override
public void setPopupPosition(int left, int top) {
super.setPopupPosition(left, top);
if (this.isAttached()) Log.debug("setPos:"+this.getAbsoluteLeft() +";"+this.getAbsoluteTop());
}
It gets the proper position and I hope it is the right way to do it and setPopupPosition is called every time. You will even call it manually when using setPopupPositionAndShow.
I think it will be wise to let this question stay at SO "for future generations".
Upd. If you plan to call center(...) or some similar method of your dialog, be aware that setPopupPosition will be called twice or more times (may be first time with 0, 0), even if you'll check if it isAttached(). Add some additional check to ensure that positions are correct in current call.
I can't get my head round this one. I've tried to adhere to the MVC pattern for the first time and now have difficulties accessing the source of an ActionEvent because the ActionListener is located in a different class. But let the code do the talking...
In the "view":
// ControlForms.java
...
private JPanel createSearchPanel() throws SQLException {
...
comboBoxCode = new JComboBox(); // Field comboBoxCode -> JComboBox()
SwingUtilities.invokeLater(new Runnable() {
public void run() {
AutoCompleteSupport<Object> support = AutoCompleteSupport.install(
comboBoxCode, GlazedLists.eventListOf(jnlCodeArray));
}
}); // Auto-Complete comboBox from GlazedLists
...
public void setComboListener(ComboListener comboListener) {
comboBoxCode.addActionListener(comboListener);
}
...
}
Then, in what I term the controller, I have two different classes:
// Controller.java
public MyController() throws SQLException {
...
addListeners();
}
...
private void addListeners(){
View view = getView();
getView().getControlForm().setComboListener(new ComboListener());
}
and
public class ComboListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
System.out.println("ComboBox listened to! e = " + e.toString());
}
}
Now, e obviously doesn't give the name of the variable (which at the moment I wish it would), so I cannot if test for e.getSource().
My question is thus: is there either a) a way to query (via if for example) the source of e, or b) a less complicated way to get to the variable name?
Many, many thanks in advance for your insights and tips!
Why do you need the name of the variable? Why can't you do the event handling like this
public class ComboListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
JComboBox source = (JComboBox)e.getSource();
//do processing here
}
}
I'd think that if you need to do processing according the variable name, obviously you need different listeners for different combo boxes.
Generally, there are only two situations in which you should use a listener like that: a) you're going to handle a certain event the same way for a bunch of objects, or b) you're only going to use the listener for one object. In the latter case, I'd prefer handling the event locally anyway.
That said, the direct answer to your question is: you shouldn't have to check inside your ActionListener implementation to see whether the appropriate object is the source of the event; you should simply only add the ActionListener to that one object.
One final note: without knowing the specifics of your architecture... generally, MVC will treat all event handling as part of the View (it reduces coupling) and the View will pass commands or method calls or your own events (i.e., not Swing's) to the Controller.
I have a textbox and one suggestbox. I attach a value change and key up handler to the text box such that whatever the user types (or pastes) into the text box is echo-ed inside the suggestbox. I can get the suggestbox to display the suggestion list by calling showSuggestionList on each value change and key up event.
Now, how do I get the suggestbox to automatically choose the first item in the suggestion list?
One of the methods I tried is to programatically simulate key presses, i.e
suggestBox.setFocus(true);
NativeEvent enterEvent = Document.get().createKeyPressEvent(false, false, false, false, KeyCodes.KEY_ENTER);
DomEvent.fireNativeEvent(enterEvent, suggestBox);
textBox.setFocus(true);
This doesn't work at all. The enter key isn't simulated. Another possible solution is to extend SuggestionBox.SuggestionDisplay, but I'm not too sure how to that. Any pointers appreciated.
Update: I'm still working on this and trying various methods.
Here, I tried to implement my own SuggestionDisplay by subclassing DefaultSuggestionDisplay and overriding getCurrentSelection() to make accessible from my class. This doesn't work either. Null is returned.
private class CustomSuggestionDisplay extends DefaultSuggestionDisplay {
#Override
protected Suggestion getCurrentSelection() {
return super.getCurrentSelection();
}
}
suggestBox.setAutoSelectEnabled(true);
textBox.addKeyUpHandler(new KeyUpHandler() {
public void onKeyUp(KeyUpEvent event) {
suggestBox.setValue(textBox.getText(), true);
suggestBox.showSuggestionList();
if (suggestBox.isSuggestionListShowing()) {
String s = ((CustomSuggestionDisplay) suggestBox.getSuggestionDisplay()).getCurrentSelection().getDisplayString();
Window.alert(s);
}
}
});
Here, I tried to attach a value change handler to the SuggestBox, and casting the event type to SuggestOracle.Suggestion. Again, null is returned.
suggestBox.addValueChangeHandler(new ValueChangeHandler<String>() {
public void onValueChange(ValueChangeEvent<String> event) {
String s = ((SuggestOracle.Suggestion) event).getDisplayString();
Window.alert(s);
}
});
Use suggesBox.setAutoSelectEnabled(true)
Here more info about the SuggestBox of GWT:
You could try using addSelectionHandler in conjunction with setAutoSelectEnabled to receive an event whenever a suggestion is selected. You could also have your Oracle send a message when it suggests something, or your Display send a message when it displays a list:
public class AutomaticallySelectingSuggestionDisplay extends SuggestBox.DefaultSuggestionDisplay {
#Override
protected void showSuggestions(SuggestBox box, Collection<? extends SuggestOracle.Suggestion> suggestions, boolean isDisplayHtml, boolean isAutoSelectEnabled, SuggestBox.SuggestionCallback callback) {
super.showSuggestions(box, suggestions, isDisplayHtml, isAutoSelectEnabled, callback);
fireValueChangeEventWithFirstSuggestion(suggestions);
}
}
This idea feels a little muddled to me, so I hope you can find a solution just using event handlers.