how to check the fragment is visible to user in Xamarin Android - android-fragments

I want to show or hide a subview in a fragment when it is shown or hidden, but no way to check the fragment is visible to user.
In android native, it seems to have a method, but Xamarin no.
Do you have any special way to get it?
I can see only a property for fragment.
public override bool UserVisibleHint {
get {
return base.UserVisibleHint;
}
set {
base.UserVisibleHint = value;
}
}
But I need a method to check this.
thanks.

You can use the IsVisible property on the Fragment (see: https://developer.xamarin.com/api/property/Android.App.Fragment.IsVisible/)
Additionally, you can override the OnHiddenChanged method on your fragment class to get notified when the Fragment's visibility changes
it seems to have a method, but Xamarin no.
What method are you referring to?

Related

Android TV: Disable collapsing on info_field on ImageCardView

I'm working with Android TV for the first time and I'm learning to use Leanback by modifying the example tv app that is provided.
The issue I'm having is that when I press left on the first item in the lists the navigation drawer opens and focus goes to the headers in the navigation drawer. When this happens, the info_field view in the ImageCardViews collapse behind the image.
What happens: The info field on the ImageCardView hides when I open the navigation drawer.
What I want to Happen: The info field remains visible when I open the navigation drawer.
I'm sure there's a way to do this because I've seen it in some Android TV apps, like Twitch. What's the best way to have the info_field visible when the navigation drawer is open?
I've worked out how to do it. In the CardPresenter, in onCreateViewHolder, when creating the ImageCardView I've overridden the BaseCardView method, setActivated(boolean activated) to always pass 'true' into it's super. And then call setActivated so that it's activated from the beginning. Like this:
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent) {
ImageCardView cardView = new ImageCardView(parent.getContext()) {
#Override
public void setActivated(boolean activated) {
super.setActivated(true);
}
#Override
public void setSelected(boolean selected) {
updateCardBackgroundColor(this, selected);
super.setSelected(selected);
}
};
cardView.setActivated(true);
cardView.setFocusable(true);
cardView.setFocusableInTouchMode(true);
return new ViewHolder(cardView)
}
So that did the trick for me. The ImageCardView never collapses.
I think if you look at this SO post you'll get most of the way there. The info view hides due to what leanback calls "expanding".
Try just calling enableMainFragmentScaling(false); in your BrowseFragment and see if that does what you want. If it doesn't feel like exactly what you want, refer to the post I linked to.
Additionally, if you've tried what I recommend in the linked SO post, you could also call the API on the BaseCardView setInfoVisibility() and pass it CARD_REGION_VISIBLE_ALWAYS. This just requires calling on a reference to your card which shouldn't need an override of the Presenter or Card.

dialogPostRun method in RunBaseReport

I have a RunBaseReport which contains overrided dialog method where I'm adding couple of my controls. One of those controls is a combobox.
Controls enabled() property should be changed when I'm modifying combobox.
So basically I need to know when the value of my dfReportType dialog field changes.
public Object dialog(Object dialog)
{
DialogRunbase dialog = dialog;
;
//adding my combobox
dfReportType = dialog.addFieldValue(typeid(ReportType), ReportType:DefaultType);
//adding some other controls here
return dialog;
}
According to many articles that I found I need to override dialogPostRun Method and do something like this:
public void dialogPostRun(DialogRunbase dialog)
{
super(dialog);
dialog.dialogForm().formRun().controlMethodOverload(true);
dialog.dialogForm().formRun().controlMethodOverloadObject(this);
}
But unfortunately I don't have this method in RunBaseReport class.
Which should be there according to msdn .
Are there any other workarounds?
I'm currently on AX 2012 but I still looked at it. I have the method available in the context menu, but not on the first column. I have to go over "Plus..." to find the method in the second column.
Well, there is no dialogPostRun method in Report object that inherits RunBaseReport, but we have this method in Class that inherits RunBaseReport.
So that was my mistake. I used report object instead of class.
If you want to make custom dialog for the report but you also want to use all default controls you should:
Create class
Inherit RunBaseReport
Override dialog, getFromDialog etc.
Override lastValueElementName method
public identifiername lastValueElementName()
{
//just put name of your report object
return reportStr(YourReportName);
}
Don't forget to add main() method if you going to make call from menuItem.

Flex 3 event bubbling set to false.. how to make it bubble then?

I have a flex app with lots of nested views and popup windows..
I'd love to catch all the CHANGE events in the application at the top level.. all of them, simply to notify the user that he has changed something (trust me it makes sense in my app).
Now, I tried to add an event listener in the Application creationComplete handler like this:
private function init():void {
this.addEventListener(flash.events.Event.CHANGE, function f():void {...})
}
but it does not work.. why? I read in the docs that event bubbling for the CHANGE event is set to false before dispatching. How can I change that? Is there any other way to achieve my goal?
thanks
Try listening to events on the SystemManager instead of the Application. As far as I understand, SystemManager sits at the very top of the display list, adding the application, popups and other UI entities as children.
In Flex 3 and below, you can retrieve it via Application.application.systemManager.
Read more on the SystemManager on Deepa's blog:
http://iamdeepa.com/blog/?p=11
I am also having trouble with a group of TextArea controls where I would like to listen for the change event on their container (parent) instead.
What I did in the end was to extend the TextArea class and create a listener for the change event. From the listener I would then dispatch a custom event that could bubble.
public class BubblingTextArea extends TextArea
{
public function BubblingTextArea()
{
super();
addEventListener(TextOperationEvent.CHANGE, changeHandler);
}
private function changeHandler(event:TextOperationEvent):void
{
dispatchEvent(new ChangeBubbleEvent(ChangeBubbleEvent.BUBBLE_CHANGE));
}
}
The custom event:
public class ChangeBubbleEvent extends Event
{
public static const BUBBLE_CHANGE:String = "bubbleChange";
public function ChangeBubbleEvent(type:String, bubbles:Boolean=true, cancelable:Boolean=false)
{
super(type, bubbles, cancelable);
}
}
I am sure someone can come up with a more elegant solution since I am still quite new to Flex and AS3 myself.
As far as I know, PopUps happen outside of the Application's main displayList, so that's probably why you're not seeing bubbling. In this case, you'll need to manually add listeners to popups. The Flash change event does bubble according to the docs: http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/events/Event.html#CHANGE
I personally like to use a framework such as RobotLegs or Parsley.
The basic idea is that each view and popup gets a mediator. The mediator's job is to communicate between the view and the command/model. Those mediators can listen directly to the view and the view's components.

Why is 'textField' not instantiated when I subclass TextArea in Flex?

I'm experimenting with TextArea and inheritance to implement some additional functionality on the protected textField property.
Unfortunately, when I create a new instance of the subclass, this property is set to null. I'm probably misunderstanding the way super() works, but I thought it would have been instantiated after the constructor finished.
Here's a small snippet of code which extends TextArea:
public final class ExtTextArea extends TextArea {
public function ExtTextArea() {
super();
}
public function testTextField():void {
if (textField == null)
Alert.show("null!");
}
}
}
The invoking code is simple:
var extTextArea:ExtTextArea = new ExtTextArea();
extTextArea.testTextField();
The Alert in ExtTestArea appears every time I run this code.
Why is this? Is there something more I need to do to access the textField property?
Since textField is "the internal UITextField that renders the text of this TextArea" I believe it will remain null until you add it to the display via .addChild(...). I ran a quick test to verify that once I've added it to the display, it is no longer null. You might want to add an event handler to the "creation complete" event and adjust it at that point (I think).
The Flex SDK comes with source code, so you can take a peek and see when this field is initialized. It is not initialized in the constrcutor, but you will see that a new TextField instantiated by createChildren(), which is called when the component is added to a layout container.

FLEX: Programmatically remove Alert?

I need to programmatically remove an alert.
This is why:
My application uses BrowserManager to enable deep linking based off of the content in the #hash part of the url. If an alert is currently up, and the user hits the back button, the application will revert back to its previous state. But the Alert will still be up, and in many cases irrelevant at that point.
So is there a way to programmatically remove the Alert? so when the hash fragment changes I can remove it.
Thanks!
It turns out the Alert.show function returns an Alert reference and then just uses PopUpManager to add it to the display list. so if you capture the return reference when you call Alert.show you can tell PopUpManager to remove it. :)
You can do this by keeping the Alert object as member data, and then setting its visible property to false when you're done with it. Next time you need to show an Alert, don't create a new one - grab the one you've already created and set its properties, then set visible to true again.
private var myAlert : Alert;
public void showAlert( message: String, title : String ) : void
{
hideAlert();
myAlert = Alert.show( message, title, Alert.OK | Alert.NONMODAL );
}
public void hideAlert() : void
{
if( myAlert != null && myAlert.visible ) {
myAlert.visible = false;
}
}
I don't think that is possible.
You can create your own alert component subclassing TitleWindow and then use PopupManager to show/hide them.

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