I've a CellTable to which I attach a click handler(via addDomHandler). Then I've added a custom cell which handles onBrowserEvent(...).
I'd like to stop the event to propagate in the cell's onBrowserEvent so that the table handler is not invoked anymore. Is this possible?
table = new CellTable();
table.addDomHandler(new ClickHandler() {
#Override
public void onClick(final ClickEvent pEvent) {
Trace.info("this shouldn't trigger");
}
}, ClickEvent.getType());
table.addColumn(new IdentityColumn<MyVO>(new MyCell()));
class MyCell extends AbstractCell<MyVO> {
#Override
public void onBrowserEvent(com.google.gwt.cell.client.Cell.Context pContext, Element pParent,
Handle<DnSuggestionDetailsVO> pValue, NativeEvent pEvent,
ValueUpdater<Handle<DnSuggestionDetailsVO>> pValueUpdater) {
Trace.info("cell onBrowserEvent handled, propagation should stop here!");
pEvent.stopPropagation();
}
}
Thank you!
It's easier to cancel an event before it reaches the cell:
table.addCellPreviewHandler(new Handler<Item>() {
#Override
public void onCellPreview(CellPreviewEvent<Item> event) {
//do something
event.setCancelled(true);
}
});
Note that CellPreviewHandler already monitors all events within a table. You can use it for your ClickEvent as well (with finer control like which column is clicked) instead of adding a ClickHandler to the entire table.
Related
I have Label in view, I need that Label's view in my ViewModel. I am using Dependency Service to set focus on Controls for Accessibility service, DS requires view as a param.
This is my Label
<Label
AutomationProperties.IsInAccessibleTree="{Binding ShowNoResults}"
IsVisible="{Binding ShowNoResults}"
Text="{Binding ResultsHeader}"/>
I tried Command but Label doesn't support command. Below code also not working
var view = GetView() as HomeworkView;
I am getting view always null. How can I fix this?
I am not quite sure what are you trying to achieve, but you can't access the View elements from you view model.
If you want to do something with the control, you can use the messaging center to do it, here is an example
in your ViewModel
MessagingCenter.Send(this, "your message here");
then in your page, you need to subscribe to this message from that view model and do the desired action
MessagingCenter.Instance.Unsubscribe<ViewModelClassNamedel>(this, "your message here");
MessagingCenter.Instance.Subscribe<ViewModelClassName>(this, "your message here", (data) =>
{
this.youControlName.Focus();
});
More detail added to Mohammad's answer.
Message Center doc.
In your ViewModel (with class name "YourViewModel"):
// Here we use control name directly.
// OR could make an "enum" with a value for each control.
string controlName = ...;
MessagingCenter.Send<YourViewModel>(this, "focus", controlName);
then in your page, subscribe to this message and do the desired action
.xaml.cs:
protected override void OnAppearing() {
{
base.OnAppearing();
// Unsubscribe before Subscribe ensures you don't Subscribe twice, if the page is shown again.
MessagingCenter.Instance.Unsubscribe<YourViewModel>(this, "focus");
MessagingCenter.Instance.Subscribe<YourViewModel>(this, "focus", (controlName) =>
{
View v = null;
switch (controlName) {
case "name1":
v = this.name1;
break;
case "name2":
v = this.name2;
break;
}
if (v != null) {
//v.Focus();
// Tell VM to use v as view.
((YourViewModel)BindingContext).SetFocus(v);
}
});
}
protected override void OnDisappearing() {
MessagingCenter.Instance.Unsubscribe<YourViewModel>(this, "focus");
base.OnDisappearing();
}
If need to pass View v back to VM, because that has the logic to use it:
public class YourViewModel
{
public void SetFocus(View view)
{
... your code that needs label's view ...
}
}
Not tested. Might need some slight changes. Might need
...(this, "focus", (sender, controlName) =>
instead of
...(this, "focus", (controlName) =>
UPDATE
Simple approach, if there is only ONE View that is needed in VM.
public class YourViewModel
{
public View ViewToFocus { get; set; }
// The method that needs ViewToFocus.
void SomeMethod()
{
...
if (ViewToFocus != null)
... do something with it ...
}
}
public class YourView
{
public YourView()
{
InitializeComponent();
...
// After BindingContext is set.
((YourViewModel)BindingContext).ViewToFocus = this.yourLabelThatShouldBeFocused;
}
}
ALTERNATIVE: It might be cleaner/more robust to set ViewToFocus in page's OnAppearing, and clear it in OnDisappearing. This ensures it is never used while the page is not visible (or in some delayed action after the page has gone away). I would probably do it this way.
protected override void OnAppearing()
{
base.OnAppearing();
((YourViewModel)BindingContext).ViewToFocus = this.yourLabelThatShouldBeFocused;
}
protected override void OnDisappearing()
{
((YourViewModel)BindingContext).ViewToFocus = null;
base.OnDisappearing();
}
I'm trying to show a callout when navigating from View A (form view) to View B (map view). I pass the record detail for the callout from View A to View B and it's bound to viewmodel of View B.
I would like to access the LoadStatusChanged event on the Map property of the Esri MapView control while adhering to MVVM architecture. Here is what my control looks like:
<esri:MapView x:Name="mapViewMain"
Map="{Binding MainMap}"
Grid.Row="0"
InteractionOptions="{Binding MapViewOptions}"
GraphicsOverlays="{Binding GraphicsOverlays}">
<esri:MapView.Behaviors>
<bh:ShowCalloutOnTapBehavior CalloutClickCommand="{Binding GoToDetailCommand}" />
<bh:ShowCalloutOnDataReceivedBehavior MeterMasterRequest="{Binding RequestParameters}" Map="{Binding MainMap}" />
</esri:MapView.Behaviors>
</esri:MapView>
I think I need to create a behavior that will take in the Map, wait for it to finish load, then show callout (results of MeterMasterRequest) on MapView (the ShowCallout method is on MapView control).
public class ShowCalloutOnDataReceivedBehavior : BehaviorBase<MapView>
{
public static readonly BindableProperty MeterMasterRequestProperty =
BindableProperty.Create(nameof(MeterMasterRequest), typeof(MeterMasterRequest), typeof(ShowCalloutOnDataReceivedBehavior));
public static readonly BindableProperty MapProperty =
BindableProperty.Create(nameof(Map), typeof(Map), typeof(ShowCalloutOnDataReceivedBehavior));
public MeterMasterRequest MeterMasterRequest
{
get { return (MeterMasterRequest)GetValue(MeterMasterRequestProperty); }
set { SetValue(MeterMasterRequestProperty, value); }
}
public Map Map
{
get { return (Map)GetValue(MapProperty); }
set { SetValue(MapProperty, value); }
}
How can I bind to the Map event from here? I don't know how I can get BehaviorBase to be of type Map. I seem to only be able to set behaviors at MapView level.
You can access the Map from the MapView.Map property and the MapView is passed in to the OnAttachedTo and OnDetachingFrom methods of the Behavior class. I see you have a BehaviorBase, which hopefully has the OnAttachedTo and OnDetachingFrom overrides still marked as protected virtual so you can override them in your ShowCalloutOnDataReceivedBehavior class
Override the OnAttachedTo method and then subscribe to the LoadStatusChanged event, override OnDetachingFrom so you can unsubscribe like so:
protected override void OnAttachedTo(MapView bindable)
{
base.OnAttachedTo(bindable);
bindable.Map.LoadStatusChanged += Map_LoadStatusChanged;
}
protected override void OnDetachingFrom(MapView bindable)
{
base.OnDetachingFrom(bindable);
bindable.Map.LoadStatusChanged -= Map_LoadStatusChanged;
}
private void Map_LoadStatusChanged(object sender, Esri.ArcGISRuntime.LoadStatusEventArgs e)
{
// Do stuff when LoadStatusChanged event is fired on the Map
}
I have a table and a button and I want to emit an event ItemsSelected with the selected items of the table when the button is clicked.
The button should not know the table and it should remain only as a stream of clicks.
So this solution is discarded:
final ETable table = ...
PublishSubject<ItemSelected> selected = PublishSubject.create();
button.addSelectionListener(new SelectionListener(){
#Override
public void widgetSelected(SelectionEvent e) {
for (TableItem item : table.getSelection()) {
selected.onNext(new ItemSelected(item));
}
}
});
I would prefer a way to compose the click stream of the button with the item selection stream of the table in order to keep loose coupling between this two elements.
Because the table allows multiple selection I must first scan the items selected in order to emit an event with all the items. Something like:
public static class ItemsSelected<T> {
final List<T> items = new ArrayList<T>();
}
public abstract static class ItemSelection<T> {
public abstract void apply(ItemsSelected<T> selection);
}
public static class ItemUnselected<T> extends ItemSelection<T> {
final T item;
public ItemUnselected(T item) {
this.item = item;
}
public void apply(ItemsSelected<T> selection) {
selection.items.remove(item);
}
}
public static class ItemSelected<T> extends ItemSelection<T> {
final T item;
public ItemSelected(T item) {
this.item = item;
}
public void apply(ItemsSelected<T> selection) {
selection.items.add(item);
}
}
public static class ObservableTable<T> extends Table {
private PublishSubject<ItemSelection<T>> clicks = PublishSubject.create();
public Observable<ItemsSelected<T>> selection = clicks.scan(new ItemsSelected<T>(),
new Func2<ItemsSelected<T>, ItemSelection<T>, ItemsSelected<T>>() {
#Override
public ItemsSelected<T> call(ItemsSelected<T> t1, ItemSelection<T> t2) {
// breaking events immutability
t2.apply(t1);
return t1;
}
});
public ObservableTable(Composite parent, int style) {
super(parent, style);
this.addSelectionListener(new SelectionListener() {
#SuppressWarnings("unchecked")
#Override
public void widgetSelected(SelectionEvent e) {
if (((TableItem) e.item).getChecked())
clicks.onNext(new ItemSelected<T>((T) e.item.getData()));
else
clicks.onNext(new ItemUnselected<T>((T) e.item.getData()));
}
#Override
public void widgetDefaultSelected(SelectionEvent e) {
}
});
}
}
Then, I must combine the table.selection stream with the button.clicks stream in a selectionForAction stream. The idea is that when a ButtonClick is emitted, an SelectionForAction will be emitted if and only if an ItemSelected was previously emitted.
-------S1--U1-----S2---S3--------- table.clicks
(scan)
-------(1)--()---(2)---(2,3)------ table.selection
----O----------O-------------O---- button.clicks
(?)
-----------------------------(2,3) selectionForAction
So, wich operation should I use?
Zip: It doesn't work because if I click the button and later select an item, it should not do nothing, but with zip it will emit an event.
Join: I end up with a "solution" using join but it doesn't seem to be a good one. Somethinkg like:
table.selection.join(button.clicks, new Func1<ItemsSelected,Observable<Long>>() {
#Override
public Observable<Long> call(ItemsSelected t) {
// it doesn't seem a good idea
return Observable.timer(1, TimeUnit.DAYS);
}
}, new Func1<ClickEvent, Observable<Long>>() {
#Override
public Observable<Long> call(ClickEvent t) {
// this makes the ClickEvent be dropped if there is no previous ItemsSelected event emitted
return Observable.timer(1, TimeUnit.MILLISECONDS);
}
}, new Func2<ItemsSelected, ClickEvent, SelectionForAction>() {
#Override
public SelectionForActioncall(ItemsSelected t1, ClickEvent t2) {
return new SelectionForAction(t1.items);
}
});
Any idea?
I've found the operator that I needed to achieve the join behaviour with a very large time unit (DAYS in the example) and a very small one (MILLISECONDS).
With a variant of sample that takes another Observable as the sampler I could emit an event A only after an event of B would be emitted.
In my example the click acts as the sampler and the stream selection emits the events that I'm interested in. (This also requires to ignore the last event that is being emitted when the stream completes).
Another possible solution will be use the buffer(boundary):
The clicks stream would act as the boundary and I could avoid the scan operator because the list of items selected is created by the buffer operator. However with this solution I would not be considering unselection.
So, with sample I've achieved my original goal, however, I'm not happy with the way I handle items unselection and the final list of items selected.
In this case I need to maintain the state of the items selected in order to perform some operation on all of them when a ClickEvent occurs.
I could subscribe to the items selection/unselection and maintain a List of the items selected but then I'll have lost the possibility of compose the clicks observable with the selection observable.
With scan I maintain state and also keep the composability of observables, but representing the list of current selection as an event seems a little forced, in fact this represents a new issue: if I select x items and then click the button, an event with the selection is being emitted as expected, but if neither the items are unselected nor a new one is selected and then click again the button, nothing happens. So, it seems that selection doesn't fit as an event.
I have an MVC application in which I have to update the view with the current value of a stream.
In the model I have this method:
public Observable<Integer> getStreamInstance(){
if(stream == null){
this.stream = Observable.create((Subscriber<? super Integer> subscriber) -> {
new HeartbeatStream(frequence,subscriber).start();
});
}
return stream;
}
which I use in the controller to get the stream. Then, in the controller I have these two methods:
public void start(){
this.sb = stream.subscribe((Integer v) -> {
view.updateCurrValue(v);
});
}
public void stop(){
this.sb.unsubscribe();
}
With the start method I simply update a label in the view with the current value.
This works fine until I try to stop the updating with the unsubscribing; infact, when I press the button "stop" in the view, the label keeps updating with the current value and, if I press "start" again, the label shows the values from two different streams, the one that I first created with the first "start" and the second that seems has been created with the second pressing of "start".
Where am I wrong?
EDIT:
public class HeartbeatStream extends Thread{
private Subscriber<? super Integer> subscriber;
private int frequence;
private HeartbeatSensor sensor;
public HeartbeatStream(int freq, Subscriber<? super Integer> subscriber){
this.frequence = freq;
this.subscriber = subscriber;
sensor = new HeartbeatSensor();
}
public void run(){
while(true){
try {
subscriber.onNext(sensor.getCurrentValue());
Thread.sleep(frequence);
} catch (Exception e) {
subscriber.onError(e);
}
}
}
This is the HeartbeatStream class. HeartbeatSensor is a class that periodically generates a value that simulates the heartbeat frequence.
I'm guessing you tried to periodically signal some event that triggers the screen update. There is an operator for that:
Observable<Long> timer = Observable.interval(period, TimeUnit.MILLISECONDS,
AndroidSchedulers.mainThread());
SerialSubscription serial = new SerialSubscription();
public void start() {
serial.set(timer.subscribe(v -> view.updateCurrValue(v)));
}
public void stop() {
serial.set(Subscriptions.unsubscribed());
}
public void onDestroy() {
serial.unsubscribe();
}
Observable by design unsubscribe your observer once that all items are emitted and onComplete callback is invoked.
Look this example https://github.com/politrons/reactive/blob/master/src/test/java/rx/observables/creating/ObservableSubscription.java
I guess you're not handling the unsubscribe - although I can't see what's going on in your HeartbeatStream class.
If you're creating an Observable with Observable.create then you need to handle unsubscribing explicitly with subscriber.isUnsubscribed().
Where possible use some of the utility methods to create an Observable - they handle this all for you eg Observable.just() or Observable.from().
If this doesn't help, please post your HeartbeatStream class.
See the the docs for more details:
https://github.com/ReactiveX/RxJava/wiki/Creating-Observables
https://github.com/ReactiveX/RxJava/wiki/Async-Operators
Im getting crazy about this issue. I implemented a ListView which you can add/remove TextField dinamically, but only the last TextField is removed.
An example:
// Object type which is used in the list
public class ExampleObject implements Serializable{
private String keyword;
public String getKeyword() {
return this.keyword;
}
public void setKeyword(String s) {
keyword = s;
}
}
//ListView
List<ExampleObject> keywordList = new ArrayList<ExampleObject>();
keywordList.add(new ExampleObject());
ListView keywordView = new ListView("keywordView", keywordList) {
#Override
protected void populateItem(final ListItem item) {
ExampleObject model = (ExampleObject) item.getModelObject();
item.add(new TextField("subKeyword", new PropertyModel(model, "keyword")));
// keyword remove link
AjaxSubmitLink removeKeyword = new AjaxSubmitLink("removeKeyword", myForm)
{
#Override
protected void onSubmit(AjaxRequestTarget target, Form<?> form) {
ExampleObject selected = (ExampleObject) item.getModelObject();
// I also tried deleting by index. println shows the
// selected object is the element I want to remove, so why always
// remove last object of the list?
keywordList.remove(selected);
if (target != null) {
target.addComponent(myForm);
}
}
};
item.add(removeKeyword);
// keyword add link
AjaxSubmitLink addKeyword = new AjaxSubmitLink("addKeyword", metadataForm)
{
#Override
protected void onSubmit(AjaxRequestTarget target, Form<?> form) {
keywordList.add(new ExampleObject());
if (target != null) {
target.addComponent(myForm);
}
}
};
item.add(addKeyword);
}
keywordView.setReuseItems(true);
metadataForm.add(keywordView);
Any help would be very appreciate, because I thing this issue is really a very stupid mistake but I cant get it!
Thanks
It might be as simple as getting rid of the line
keywordView.setReuseItems(true);
The reuseItems flag is an efficiency so that the page does not rebuild the ListView items unnecessarily, but it can lead to confusion such as what you're seeing.
ListView really wasn't made for use with forms though, and you'll probably be better off with another tactic entirely.
This blog entry on building a list editor form component might be useful. It will need some changes if you're not on Wicket 1.4, but similar stuff is definitely possible in Wicket 1.3, and the comments have some hints.
Read the javadoc of ListView#setReuseItems():
"But if you modify the listView model object, than you must manually call listView.removeAll() in order to rebuild the ListItems."
You can not use a ListView this way. Either use the members of ListView provided:
removeLink(java.lang.String id, ListItem<T> item)
and
newItem(int index)
but, I never used those. If I have to display a List and be able to add remove Items dynamically, I prefer the RefreshingView.
If you do use FormComponents inside a RefreshingView, make sure you set a Reusestartegy (setItemReuseStrategy())
Bert