i have a program in flex wherein i check if a particular field is validated then the submit button is enabled. I am trying something like this:
public function init():void
{
submit.addEventListener(Event.CHANGE,enableSubmit);
}
public function enableSubmit(event:TextInput):void
{
//some code to enable the button
}
I can call init in creation complete to add event listener to submit! is this the correct way to do it ? Please help!
Yes, you can call the init in the creationComplete.
The only thing you need to change in your code is the parameter of the enableSubmit from TextInput to Event because the event is passed by parameter, like the code below:
public function enableSubmit(event:Event):void
{
//some code to enable the button
}
Also the event listener need to be added to the TextInput, so I am assuming that submit control is the TextInput submit.addEventListener(Event.CHANGE,enableSubmit);
Related
(Invalid question. You do not need to refer to it. Thank you.)
Solution : Use a common variable not $event.
I want to run the event on the other buttons.
I use $event, but I can not call function immediately.
.html
<p-fileUpload (onSelect)="runSelect($event)"
accept="image/*" #imageUpload></p-fileUpload>
<button (click)="callImageSelect()" #button2></button>
When button2 is pressed, I want to run (onSelect) event on #imageUpload.
(onSelect) have a parameter. (event.files: List of selected files)
If press button1 to run ,
and I want to put the default value in $event.
So the way I found is to use viewChild.
.ts
#ViewChild('imageUpload') imageUpload;
...
callImageSelect() {
this.imageUpload.**onSelect()**; // In this section, call (onSelect).
}
runSelect(event) {
event.files.push(defalut);
// Here I put the default value for event.
}
Is there a good way?
Thank you for your advice.
What you want is to trigger event onSelect. The point to be noted here is onSelect is not a function but event. You should not call the event instead call the function which actually triggers it.
Since you are using onSelect which is custom event so you must be using some Directive for the same. So what you should do is, access the Directive inside the component and call the function which triggers the event (EventEmitter);
Sue-do code
#Directive(selector="my-directive")
public class MyDirective {
value : string;
onSelect = new EventEmitter();
public selectionMade(){
this.onSelect.emit(value);
}
}
Component html
<button (onSelect)="runSelect($event)" myDirective #myDirective="myDirective"></button>
<button (click)="clickTest()" #button2></button>
Component ts
#ViewChild('myDirective') myDirective : MyDirective;
...
clickTest() {
this.myDirective.selectionMade(); // In this section, call (onSelect).
}
I often have the requirement to dispatch a flash.events.Event with soem custom String text, like:
protected function mouseClicked(event:Event) {
//here I'd want to notify anyone interested in the button click,
//and also transfer the name of the button (or whatever) that was clicked - assume some dynamic value
dispatchEvent(new Event("myMouseEvent"), button.name));
}
Of course the above event is invalid. But is there any event that can be used for that type of events? Maybe the TextEvent, but I don't know if I'd be misusing it here.
To include additional data with your events, create a custom event class by extending Event (or any sub-class of Event) and adding your own properties. For example:
class NameEvent extends Event {
public static const NAME_CLICK:String = "nameClick";
public var name:String;
public function NameEvent(type:String, name:String) {
this.name = name;
super(type);
}
}
dispatchEvent(new NameEvent(NameEvent.NAME_CLICK, button.name));
Note that your event type strings ("nameClick" in this example) should be globally unique, otherwise listeners could get them confused with other event types. For example "click" is already expected to be a MouseEvent. I often add prefixes to my custom event types, for example "NameEvent::click".
Another option that does not require creating a custom event is to rely on the expected target to get additional data. For example:
// dispatch a custom event from a Button
dispatchEvent(new Event("myClick"));
// handler for "myClick" events on the button
function myClicked(e:Event):void {
var button:Button = e.target as Button;
trace(button.name);
}
This is not as flexible and also more fragile than using a custom event class, but sometimes a quick easy solution.
I have a mediator created in Robotlegs, and its related view would dispatch two different kinds of events. When the mediator captures the event, it would just simply dispatch the event. The problem I ran into was that the first event is re-dispatched flawlessly, but the 2nd event was not dispatched.
However, if I manually assign a different handler to the 2nd event, the event is properly captured.
Below is the relevant code:
public class MyMediator extends Mediator
{
[Inject]
public var view:MyView;
public override function onRegister():void
{
super.onRegister();
addViewListener( SomeEventTypeA.COOL_EVENT, dispatch, SomeEventTypeA ); // This event is dispatched correctly
addViewListener( SomeEventTypeB.STUCK, dispatch, SomeEventTypeB ); // This one is not correctly dispatched
//A twist, if I uncomment the following code, the event is captured by its handler
//addViewListener( SomeEventTypeB.STUCK, view_stuck, SomeEventTypeB );
}
private function view_stuck( event:SomeEventTypeB ):void
{
//ah ha, this is called correctly if the above relevant line is uncommented
}
}
Found the cause:
The event needs to have a proper clone method in order to be re-dispatched correctly. See related link:
http://knowledge.robotlegs.org/kb/application-architecture/why-doesnt-my-event-trigger-the-command-it-is-mapped-to
I was trying to filter a combo box dataprovider based on the values in the text boxes . When the contents of the dataprovider changes Combo box automatically calls change event method . Please find the sample code below.
Filter Utility Function:
private function filterLocations(event:FocusEvent):void {
locationsList1.filterFunction = filterUtility;
locationsList1.refresh();
}
public function filterUtility(item:Object):Boolean {
// pass back whether the location square foot is with in the range specified
if((item.SQUARE_FOOTAGE >= rangeText1.text) && (item.SQUARE_FOOTAGE rangeText2.text))
return item.SQUARE_FOOTAGE;
}
// THIS WOULD BE CALLED WHEN COMBO BOX SELECTION IS DONE
private function selectLocationsReports(event:ListEvent):void {
selectedItem =(event.currentTarget as ComboBox).selectedItem.LOCATION_ID;
}
When the DataProvider gets refreshed its automatically calls change method and was throwing Null Pointer function because its prematurely calling the above selectLocationsReports method and its throwing error.
Can somebody let me know how to stop the CHANGE event from propogation when the dataprovider is refreshed.
You can't stop a CHANGE event, just don't add an event listener unless you are prepared to get the event. I don't see where your event listener for Event.CHANGE is in the code above.
Just be sure that you don't addEventListener(Event.CHANGE, selectLocationsReports) until your ComboBox is ready for it.
The other thing to do (on top of Kekoa's response) is put an if statement in the event handler, and check to make sure the data is there before you begin working with it.
A handy syntax I use frequently for this is
if(dataprovidername) {
}
I've done a lot of reading through forum posts and tutorials, but I still can't wrap my brain round events and event listeners. I have a pretty simple example, but I can't get it to work.
I have an arrayCollection of custom objects in a repeater, when one of those objects is clicked, I want a different componenet to display data associated with that object.
Here's what I have, but the listener never responds (the dispatcher seems to be working though, because the new event is created and I can see the trace with the proper output.) I suspect it is because when I call addEvent Listener, I am doing so on the wrong object. My understanding is that the object that will display the object data is the object that should have the event listener, and listen for all events of this nature, but maybe I misunderstood.
My custom event:
public class SelectObjectEvent extends Event
{
public function SelectObjectEvent(customEventString:String, myObject:customObject)
{
super(customEventString, true, false);
trace(customEventString+" "+myObject);
}
}
}
My custom object has the following function which is called on click:
public function selectObject(myObject:customObject):void
{
dispatchEvent(new SelectObjectEvent("OBJECT_SELECTED", customObject));
}
And the component I want to display the selected object has the following constructor:
public function SelectedObjectDisplayClass()
{
addEventListener("OBJECT_SELECTED", this.showObject)
}
public function showObject(event:Event):void
{
trace("Show object: "+event);
}
It's not quite clear where your last two code chunks are, but it looks like you need to be calling addEventListener on the object that extends EventDispatcher.
That is, if your second chunk belongs to a custom object called Clickable, which extends EventDispatcher and calls dispatchEvent() when clicked, then your component should be calling myClickable.addEventListener(...) where myClickable is an instance of Clickable. Does that make sense?
But assuming your 3rd code chunk is not in the same class as the second, it doesn't look like you're doing that. You're adding a listener to the class that owns the third chunk of code, which I gather is not the one that extends EventDispatcher.
Just a quick glance at your code and notice that your dispatchEvent second parameter is the class not the instance of the object. Shouldn't this be myObject?
public function selectObject(myObject:customObject):void
{
dispatchEvent(new SelectObjectEvent("OBJECT_SELECTED", **customObject**));
}