i need to update a textView from my asynctask. I have an custom adapter for the listview and there i want to have a countdown for each entry. I will start the asynctask for each entry from my Adapter. How can i update the textview each second from the asynctask?
Thanks for help :)
If you post your code, I can give you a better answer. However, a common way to update views periodically is by using Handlers.
private final Handler mHandler = new Handler(); //intialize in main thread
public void test() {
mHandler.postDelayed(new Runnable() {
#Override
public void run() {
mTextView.setText("hello");
}
}, 1000);
}
You can do something like this (this will add an entry to a list view every one second). I have used the normal ArrayAdapter to add a string. You can use your custom adapter to do something similar. The publishProgress() method basically triggers the onProgressUpdate() method which hooks to the UI thread and displays the elements getting added.:
class AddStringTask extends AsyncTask {
#Override
protected Void doInBackground(Void... params) {
for(String item : items) {
publishProgress(item);
SystemClock.sleep(1000);
}
return null;
}
#Override
protected void onProgressUpdate(String... item) {
adapter.add(item[0]);
}
#Override
protected void onPostExecute(Void unused) {
Toast.makeText(getActivity(), "Done adding string item", Toast.LENGTH_SHORT).show();
}
}
Related
I get the fact that it might take more than 10 lines of code (hopefully not more than 50), but I was wondering if you could help me anyway.
I'm trying to update one user's UI thread at runtime, based on another user's input. I've created a basic project which implements three predefined users (jim, tom and threeskin). I'd like to send a message from jim to tom and have it appear as a new Label object in tom's UI, without threeskin ever knowing about it, even though they're all logged in. Oh, and jim shouldn't have to refresh his page. The label should just spawn on screen out of it's own accord.
To say that I'd appreciate some help would be the understatement of the decade.
public class User {
public String nume;
public User(String nume) {
super();
this.nume = nume;
}
}
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
public class Engine implements ServletContextListener {
public static ArrayList<User>userbase;
public void contextDestroyed(ServletContextEvent arg0) { }
public void contextInitialized(ServletContextEvent arg0) {
System.out.println("This code is running at startup");
userbase =new ArrayList<User>();
userbase.add(new User("jim"));userbase.add(new User("tom"));userbase.add(new User("threeskin"));
}
}
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
public class InfigeUI extends UI {
User us3r;
#WebServlet(value = "/*", asyncSupported = true)
#VaadinServletConfiguration(productionMode = false, ui = InfigeUI.class)
public static class Servlet extends VaadinServlet {}
protected void init(VaadinRequest request) {
VerticalLayout everything=new VerticalLayout();
setContent(everything);
if (us3r==null){everything.addComponent(auth());}else{everything.addComponent(main());}
}
ComponentContainer auth(){
final VerticalLayout layout = new VerticalLayout();
layout.setMargin(true);
TextField userField=new TextField();
Button login = new Button("Log in");
login.addClickListener(new Button.ClickListener() {
public void buttonClick(ClickEvent event) {
us3r=login(userField.getValue());
if (us3r!=null){
saveValue(InfigeUI.this, us3r);
layout.removeAllComponents();
layout.addComponent(main());
}else{Notification.show("I only know jim, tom and threeskin. Which one are you?");}}
});
layout.addComponent(userField);
layout.addComponent(login);
return layout;
}
User login(String nume){
for (int i=0;i<Engine.userbase.size();i++){
if (nume.equals(Engine.userbase.get(i).nume)){return Engine.userbase.get(i);}
}
return null;
}
static void saveValue(InfigeUI ui,User value){
ui.us3r=value;
ui.getSession().setAttribute("something", value);
VaadinService.getCurrentRequest().getWrappedSession().setAttribute("something", value);
}
ComponentContainer main(){
VerticalLayout vl=new VerticalLayout();
Label label=new Label("This is the post-login screen");
String name=new String(us3r.nume);
Label eticheta=new Label(name);
TextField to=new TextField("Send to");
TextField message=new TextField("Message");
Button sendNow=new Button("Send now!");
vl.addComponent(eticheta);
vl.addComponent(label);
vl.addComponent(eticheta);
vl.addComponent(to);
vl.addComponent(message);
vl.addComponent(sendNow);
return vl ;
}
}
Basically you want three things
UI updates for a user which does no action himself, or in other words a message sent from the server to the browser. To enable this, you need to annotate the UI class using #Push. Otherwise, the update will only be shown when the user does something which causes a server visit, e.g. clicks a button
Some way of sending messages between UI instances (there is one UI instance per user). You can use some message bus implementation for this (CDI, Spring, ...) or you can make a simple on using a static field (static fields are shared between all users). See e.g. https://github.com/Artur-/SimpleChat for one way of doing it. It's also a good idea here to avoid all *.getCurrent methods as they in many cases will refer to another UI than you think (e.g. sender when you are in the receiver code), and you will do something else than you intend.
Safely update a UI when a message arrives. This is done using UI.access, also visible in the chat example.
First of all you need to enable the server push on your project help
based on Vaadin Documentation.
However, below code example will give what you want:
Create an Broadcast Listener Interface:
public interface BroadcastListener {
public void receiveBroadcast(final String message);
}
The Broadcaster Class:
public class Broadcaster {
private static final List<BroadcastListener> listeners = new CopyOnWriteArrayList<BroadcastListener>();
public static void register(BroadcastListener listener) {
listeners.add(listener);
}
public static void unregister(BroadcastListener listener) {
listeners.remove(listener);
}
public static void broadcast(final String message) {
for (BroadcastListener listener : listeners) {
listener.receiveBroadcast(message);
}
}
}
Your UI with Push Enalbed (via Annotation):
#Push
public class BroadcasterUI extends UI implements BroadcastListener {
#Override
protected void init(VaadinRequest request) {
final VerticalLayout layout = new VerticalLayout();
layout.setMargin(true);
setContent(layout);
final TextArea message = new TextArea("",
"The system is going down for maintenance in 10 minutes");
layout.addComponent(message);
final Button button = new Button("Broadcast");
layout.addComponent(button);
button.addClickListener(new Button.ClickListener() {
#Override
public void buttonClick(ClickEvent event) {
Broadcaster.broadcast(message.getValue());
}
});
// Register broadcast listener
Broadcaster.register(this);
}
#Override
public void detach() {
Broadcaster.unregister(this);
super.detach();
}
#Override
public void receiveBroadcast(final String message) {
access(new Runnable() {
#Override
public void run() {
Notification n = new Notification("Message received",
message, Type.TRAY_NOTIFICATION);
n.show(getPage());
}
});
}
you can find the full link here.
I am creating an Eclipse RCP application with multiple views. One of my views is a multi-page editor view. Each of those pages has a a master/details block. I need to register all of those TableViewers as selection providers for my other view to listen to.
After much research online, I came across this article about multiple selection providers in a single view. I followed the instructions to create this selection provider for multiple viewers.
class MyMultipleSelectionProvider implements ISelectionProvider {
private final ListenerList selectionListeners = new ListenerList();
private ISelectionProvider delegate;
private final ISelectionChangedListener selectionListener = new ISelectionChangedListener() {
#Override
public void selectionChanged(final SelectionChangedEvent event) {
if (event.getSelectionProvider() == AdaptabilityProfileSelectionProvider.this.delegate) {
fireSelectionChanged( event.getSelection() );
}
}
};
/**
* Sets a new selection provider to delegate to. Selection listeners
* registered with the previous delegate are removed before.
*
* #param newDelegate new selection provider
*/
public void setSelectionProviderDelegate(final ISelectionProvider newDelegate) {
if (this.delegate == newDelegate) {
return;
}
if (this.delegate != null) {
this.delegate.removeSelectionChangedListener(this.selectionListener);
}
this.delegate = newDelegate;
if (newDelegate != null) {
newDelegate.addSelectionChangedListener(this.selectionListener);
fireSelectionChanged(newDelegate.getSelection());
}
}
#Override
public void addSelectionChangedListener(final ISelectionChangedListener listener) {
this.selectionListeners.add(listener);
}
#Override
public ISelection getSelection() {
return this.delegate == null ? null : this.delegate.getSelection();
}
#Override
public void removeSelectionChangedListener(final ISelectionChangedListener listener) {
this.selectionListeners.remove(listener);
}
#Override
public void setSelection(final ISelection selection) {
if (this.delegate != null) {
this.delegate.setSelection(selection);
}
}
protected void fireSelectionChanged(final ISelection selection) {
fireSelectionChanged(this.selectionListeners, selection);
}
private void fireSelectionChanged(final ListenerList list, final ISelection selection) {
final SelectionChangedEvent event = new SelectionChangedEvent(this.delegate, selection);
final Object[] listeners = list.getListeners();
for (int i = 0; i < listeners.length; i++) {
final ISelectionChangedListener listener = (ISelectionChangedListener) listeners[i];
listener.selectionChanged(event);
}
}
}
I added a focusListener on all of the edior's viewers so they become the delegate:
tree.addFocusListener(new FocusAdapter() {
#Override
public void focusGained(final FocusEvent e) {
editor.getSelectionProvider().setSelectionProviderDelegate(MyEditorPage.this.treeViewer);
}
});
And I registered this as the selection provider for my editor:
site.setSelectionProvider( this.selectionProvider );
Then, within my view that needs to hear about the selection, I registered a selection listener for this editor:
getSite().getPage().addSelectionListener(MyEditor.ID, this.selectionListener);
When I run the application, I see that the delegate is being changed and the selection events are being fired. However, the listener list is empty.
I am never calling addSelectionChangeListener() directly. I was under the impression that that was what the selection service is for. Am I wrong? Should I be calling it? If so, when? If not, who is supposed to be adding the listener, and why isn't it happening?
If your code is based on FormEditor (or MultiPageEditorPart) then the selection provider is set to MultiPageSelectionProvider at the end of the init method. This may be overriding your site.setSelectionProvider call.
Using:
#Override
public void init(IEditorSite site, IEditorInput input)
throws PartInitException {
super.init(site, input);
site.setSelectionProvider(this.selectionProvider);
}
should make sure your provider is the one used.
I have a vaadin 7 client widget which has a DIV element in it. I am trying to register the click event on DIV elment through Event.sinkEvents. however the browser events never get fired. Here is the piece of code
public class MyWidget extends Widget{
private final DivElement popup = Document.get().createDivElement();
public MyWidget() {
initDOM();
initListeners();
}
private void initDOM(){
popup.setClassName(STYLECLASS);
setElement(popup);
}
public void initListeners(){
Event.sinkEvents(popup, Event.ONCLICK|Event.MOUSEEVENTS);
Event.setEventListener(popup, new EventListener() {
#Override
public void onBrowserEvent(Event event) {
Window.alert("clicked"); // this never get fired.
event.stopPropagation();
}
});
}
Please suggest any pointer.
Regards,
Azhar
There is never a need to do DOM.setEventListener in a widget (and in fact it should be avoided) - just override the widget's own onBrowserEvent method after sinking those events. By sinking those events and attaching the widget to a parent, GWT has internally called setEventListener on the widget itself so that it can handle its own events.
Instead of using Event#sinkEvents, use Widget#sinkEvents. And override the widget's onBrowseEvent to handle the events.
This should do it:
public class MyWidget extends Widget{
private final DivElement popup = Document.get().createDivElement();
public MyWidget() {
initDOM();
}
private void initDOM(){
popup.setClassName(STYLECLASS)
setElement(popup);
sinkEvents(Event.ONCLICK|Event.MOUSEEVENTS);
}
#Override
public void onBrowserEvent(Event event) {
super.onBrowserEvent(event);
if(event.getTypeInt()==Event.ONCLICK){
Window.alert("Clicked");
}
}
}
Yes, Overridding the onBrowserEvent method works.
below code worked.
Event.sinkEvents(popup, Event.ONCLICK|Event.MOUSEEVENTS);
replaced with
sinkEvents(Event.ONCLICK|Event.MOUSEEVENTS);
Will sink the events on widget and not on any DIV. after that below brower event got fired.
public void onBrowserEvent(Event event) {
Window.alert("clicked"); // this never get fired.
event.stopPropagation();
}
});
I am using Cell Table of GWT 2.2 version. I want to get the name of the header column on which I have clicked. I didn't get any click event on the same.
Is there any work around by which I can accomplish my task.
Something like this? ;)
public class CellTableExample implements EntryPoint, ClickHandler {
private static class SomeEntity {
/* ... */
}
private static class ClickableTextHeader extends TextHeader {
private ClickHandler handler;
public ClickableTextHeader(String text, ClickHandler handler) {
super(text);
this.handler = handler;
}
#Override
public void onBrowserEvent(Context context, final Element elem,
final NativeEvent event) {
//maybe hijack click event
if(handler != null) {
if(Event.ONCLICK == Event.getTypeInt(event.getType())) {
handler.onClick(new ClickEvent() {
{
setNativeEvent(event);
setRelativeElement(elem);
setSource(ClickableTextHeader.this);
}
});
}
}
//default dom event handler
super.onBrowserEvent(context, elem, event);
}
}
CellTable<SomeEntity> cellTable;
TextColumn<SomeEntity> firstColumn;
TextColumn<SomeEntity> secondColumn;
TextColumn<SomeEntity> thirdColumn;
#Override
public void onModuleLoad() {
/* somehow init columns - it's not the point for this example */
cellTable.addColumn(firstColumn, new ClickableTextHeader("First column header", this));
cellTable.addColumn(secondColumn, new ClickableTextHeader("Second column header", this));
cellTable.addColumn(thirdColumn, new ClickableTextHeader("Third column header", this));
}
#Override
public void onClick(ClickEvent event) {
ClickableTextHeader source = (ClickableTextHeader) event.getSource();
Window.alert(source.getValue());
}
}
Hijacking event could look simpler if we used "simple listener interface" - i just wanted to be "semanticaly compliant with out-of-the-box Handlers" :)
I have this button cell in my CellTable
ButtonCell reListCell = new ButtonCell();
reListColumn = new Column<EmployerJobs, String>(reListCell) {
#Override
public String getValue(EmployerJobs object) {
return "ReList";
}
};
ctJobs.addColumn(reListColumn,
EmployerDashBoardConstants.EMPTYHEADERCOLUMN);
but i only want this cell to be appear if the below condition pass
public void getDateDiff(final EmployerJobs object) {
rpcService.getDateDiff(object.getJobValidDate(), new AsyncCallback<Boolean>() {
public void onFailure(Throwable caught) {
}
public void onSuccess(Boolean jobExpired) {
if(jobExpired) {
// HERE I WANT TO SHOW MY RELISTCELL, means if the job is expired only then
// there will be a button showing relist would be appear in that row ,for
// the jobs which are not expired NO button should appear..
}
}
});
}
how can i achieve this?
thanks
I agree with DTing.
Quering the backend for each cell/row is not really efficient.
I would rather put the info (jobExpired) into your EmployerJobs class and transfer the info when you request the list of your EmployerJobs to be displayed in your CellTable.
You can update the list periodically to account for changes (see the expenses sample on how to do that).
But to your initial question (hiding the cell). There are two solutions:
Use an ActionCell and override the render method.
ActionCell:
ActionCell<EmployerJobs> reListCell = new ActionCell<EmployerJobs>("ReList",
new ActionCell.Delegate<EmployerJobs>() {
#Override
public void execute(EmployerJobs object) {
// code to be executed
}
})
{
#Override
public void render(Cell.Context context,EmployerJobs value,SafeHtmlBuilder sb) {
if (value.isJobExpired()) // isJobExpired returns the field jobExpired.
super.render(context,value,sb);
}
};
reListColumn = new Column<EmployerJobs, EmployerJobs>(reListCell) {
#Override
public String getValue(EmployerJobs object) {
return object;
}
};
ctJobs.addColumn(reListColumn,
EmployerDashBoardConstants.EMPTYHEADERCOLUMN);
Use a ButtonCell and override the render method of your Column.
ButtonCell:
ButtonCell reListCell = new ButtonCell();
reListColumn = new Column<EmployerJobs, String>(reListCell) {
#Override
public String getValue(EmployerJobs object) {
return "ReList";
}
#Override
public void render(Cell.Context context,EmployerJobs object,SafeHtmlBuilder sb) {
if (value.isJobExpired()) // isJobExpired returns the field jobExpired.
super.render(context,value,sb);
}
};
ctJobs.addColumn(reListColumn,
EmployerDashBoardConstants.EMPTYHEADERCOLUMN);
Just tried Umit solution #2 ButtonCell. It works!
To link an specific action to the button, reListColumn.setFieldUpdater(new FieldUpdater....
would be needed
I tried ButtonCell solution too. But if you click in a cell who as no button then an error on client side occur:
com.google.gwt.core.client.JavaScriptException: (TypeError) #com.google.gwt.core.client.impl.Impl::apply(Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)([JavaScript object(445), JavaScript object(240), JavaScript object(637)]): parent is null
So I added this to override the Event and avoid Event if I want:
#Override
public void onBrowserEvent(com.google.gwt.cell.client.Cell.Context context,
Element parent, YourObject object, NativeEvent event) {
if (object.isCompleted())
super.onBrowserEvent( context, parent, object, event);
}
I don't know if it's the better way to do it but it works.