I have an webapp with a large collection. So my user get a text box to filter the collection.
But every time the user put in one letter the filter action starts. This is very slow some times.
So I want only get the value change event when the user stop typing for one second.
I tried it this way:
#Override
public void onValueChange( ValueChangeEvent<String> event )
{
Timer t = new Timer()
{
#Override
public void run()
{
addChangeHandler( new ChangeHandler()
{
#Override
public void onChange( ChangeEvent event1 )
{
ValueChangeEvent.fire( TextBoxPSG.this, getValue() );
}
} );
}
};
t.schedule( 15000 );
}
But this doesn't work.
Maybe someone has an Idea or the same problem.
Thanks in advance.
Do not use ValueChangeEvent. Use KeyUpEvent.
private static Timer timer = new Timer() {
#Override
public void run() {
// do you filter work;
}
};
...
myTextBox.addKeyUpHandler(new KeyUpHandler() {
#Override
public void onKeyUp(KeyUpEvent event) {
if (timer.isRunning()) {
timer.cancel();
}
timer.schedule(1000);
}
});
Related
Consider the following example, it creates an Observable that wraps another API that produces Widgets
public Observable<Widget> createWidgetObservable() {
return Observable.create(new Observable.OnSubscribe<Widget>() {
#Override
public void call(final Subscriber<? super Widget> subscriber) {
WidgetCreator widgetCreator = new WidgetCreator();
widgetCreator.setWidgetCreatorObserver(new WidgetCreator.WidgetCreatorObserver() {
#Override
public void onWidgetCreated(Widget widget) {
if (!subscriber.isUnsubscribed()) {
subscriber.onNext(widget);
}
}
#Override
public void onWidgetError(Throwable e) {
if (!subscriber.isUnsubscribed()) {
subscriber.onError(e);
}
}
});
}
});
}
Are the subscriber.isUnsubscribed() checks necessary prior to calling subscriber.onNext() and subscriber.onError()?
If so, are the checks always necessary or does it depend on the composition / subscriber that's using the observable?
Is it best practice to include the checks?
You can use them to narrow the window between an emission and an unsubscription but if you don't have loops, it is unnecessary most of the time. The more important thing is that if an unsubscription happen, you'd have to "unset" the WidgetCreatorObserver otherwise it will keep receiving and dropping data and keeping alive every reference it may hold.
WidgetCreator widgetCreator = new WidgetCreator();
WidgetCreator.WidgetCreatorObserver wo = new WidgetCreator.WidgetCreatorObserver() {
#Override
public void onWidgetCreated(Widget widget) {
if (!subscriber.isUnsubscribed()) {
subscriber.onNext(widget);
}
}
#Override
public void onWidgetError(Throwable e) {
if (!subscriber.isUnsubscribed()) {
subscriber.onError(e);
}
}
}
widgetCreator.setWidgetCreatorObserver(wo);
wo.add(Subscriptions.create(() -> widgetCreator.removeWidgetCreatorObserver(wo)));
I have this code:
searchButton.addClickHandler(new ClickHandler() {
#Override
public void onClick(ClickEvent event) {
statusLabel.setText("Searching...");
final String query = searchField.getText();
RootPanel.get("flickr").clear();
AsyncCallback<Flickr> ac=new AsyncCallback<Flickr>(){
#Override
public void onFailure(Throwable caught) {
}
#Override
public void onSuccess(Flickr result) {
for(Photo p:result.getPhotos().getPhoto())
{
flck.add(p);
}
statusLabel.setText("");
}
};
mashupService.getFlickrPhotos(query, ac);
if(!flck.isEmpty())
{
for(int i=0;i<flck.size();i++)
{
RootPanel.get("flickr").add(new HTML("<img src='http://farm"+flck.get(i).getFarm()+".staticflickr.com/"+flck.get(i).getServer()+"/"+flck.get(i).getId()+"_"+flck.get(i).getSecret()+".jpg'/><br/>"));
}
}
}
});
I want execute first onSuccess (have flick.add)... but it executes after of if(!flck.isEmpty)... and I need have flck with data but I can't...
When I press secont time the same button, flck have data of first onClick...
Thanks in advance
Move the code inside the onSuccess() method that is depended on the result of AsyncCallback.
It's clear from the name that AsyncCallback is just like a AJAX request that talks to server asynchronously means the execution of code is not sequential.
Just move if(!flck.isEmpty)... inside onSuccess() method.
I have a SuggestionBox in GWT. Is there a way to clear it when it blurs (unless the user made a selection, in which case an action should happen)?
Add a BlurHandler:
suggestionBox.getValueBox().addBlurHandler(new BlurHandler() {
#Override
public void onBlur(BlurEvent event) {
// your code goes here
}
});
Try this one using ValueChangeHandler:
Note: ValueChange event has same behavior as Blue event but it is fired only if value is changed in SuggestBox.
class MyMultiWordSuggestOracle extends MultiWordSuggestOracle {
private Set<String> values = new HashSet<String>();
#Override
public void add(String value) {
super.add(value);
values.add(value);
}
#Override
public void clear(){
super.clear();
values.clear();
}
public boolean contains(String value) {
return values.contains(value);
}
}
You code:
final MyMultiWordSuggestOracle oracle = new MyMultiWordSuggestOracle();
oracle.add("A");
oracle.add("AB");
oracle.add("BCD");
oracle.add("BCDE");
final SuggestBox suggestionBox = new SuggestBox(oracle);
suggestionBox.addValueChangeHandler(new ValueChangeHandler<String>() {
#Override
public void onValueChange(ValueChangeEvent<String> event) {
if (!oracle.contains(event.getValue())) {
suggestionBox.setValue("");
}
}
});
So I have a timer and it keeps on firing even though I cleared the Panel and loaded other model... my question is, how to cancel a timer when I unload a model?
So here is part of my code
public Display(List<Clarification> result) {
if (result.size() == 0) {
Window.alert("EMPTY");
} else {
RootPanel.get("Dev1").clear();
t = new Timer() {
public void run() {
cd = new ClarificationDispatcher();
cd.getClarificationsCount(result.size());
}
};
t.scheduleRepeating(5000);
}
I tried to cancel the Timer onUnload() method however, I don't believe it is getting called at all...
Thanks!
Steps to follow
use window.onunload event that is called when page is refreshed
first export cancelTimer() method to java script using JSNI and register cancelTimerFunction as java script function that is called on page unload
cancel timer on window close
Code:
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;
private static Timer timer = null;
public void onModuleLoad() {
exportCancelTimer();
final Label label = new Label("Hello ");
timer = new Timer() {
#Override
public void run() {
label.setText("Hello " + Math.random() * 100);
}
};
timer.scheduleRepeating(500);
RootPanel.get().add(label);
Window.addCloseHandler(new CloseHandler<Window>() {
#Override
public void onClose(CloseEvent<Window> event) {
timer.cancel();
}
});
}
public static void cancelTimer() {
if (timer != null) {
System.out.println("cancel");
timer.cancel();
}
}
public static native void exportCancelTimer() /*-{
$wnd.cancelTimerFunction = $entry(#com.x.y.z.GWTProject::cancelTimer());
$wnd.onunload = $wnd.cancelTimerFunction;
}-*/;
I am using gwt 2.3 with gwtp framework.In this application I wan to maintain a session time of 5 mins.This means if current user is not doing up to 5 min and he comes after five min then on his first event/action on screen a he should be be logged out.
In gwt there is class named Timer which can be used in this issues.But I am not getting how to recognize action of user on the screen.I did google on it, & found the code for gwt-ext.Below is the code of gwt-ext
Ext.get(“pagePanel”).addListener(“click”, new EventCallback() {
#Override
public void execute(EventObject e) {
MessageBox.alert(“On Mouse Click”);
}
});
Ext.get(“pagePanel”).addListener(“keydown”, new EventCallback() {
#Override
public void execute(EventObject e) {
MessageBox.alert(“On Key Press Click”);
}
});
In above code tag in working properly so I am attaching link from where I got this code.here
Same type of code I am looking in gwt.If there any other better way to do this then please let me know. Thanks in advance
If action/event can be really everythin, I would solve it with a
NativePreviewHandler in the following way:
boolean expired;
final Timer logoutTimer = new Timer() {
#Override
public void run() {
expired = true;
}
};
NativePreviewHandler nph = new NativePreviewHandler() {
#Override
public void onPreviewNativeEvent(NativePreviewEvent event) {
if (!expired) {
logoutTimer.cancel();
logoutTimer.schedule(300000);
} else {
// do your logout stuff here
}
}
};
Event.addNativePreviewHandler(nph);
If the user shell be logged out without a new action after 5 minutes:
final Timer logoutTimer = new Timer() {
#Override
public void run() {
// do your logout stuff here
}
};
NativePreviewHandler nph = new NativePreviewHandler() {
#Override
public void onPreviewNativeEvent(NativePreviewEvent event) {
// Of course do this only when logged in:
logoutTimer.cancel();
logoutTimer.schedule(300000);
}
};
Event.addNativePreviewHandler(nph);