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.
Related
I'm writing a program using Qt 4.8 that displays a table (QTableWidget) filled with filenames and file's params. First an user adds files to the list and then clicks process. The code itself updates the contents of the table with simple progress description. I want the table by default to be scrolled automatically to show the last processed file and that code is ready.
If I want to scroll it by hand the widget is being scrolled automatically as soon as something changes moving the viewport to the last element. I want to be able to override the automated scroll if I detect that it was the user who wanted to change view.
This behavior can be seen in many terminal emulator programs. When there's a new line added the view is scrolled but when user forces the terminal to see some previous lines the terminal does not try to scroll down.
How could I do that?
Solution:
I created an object which filters event processed by my QTableWidget and QScrollBar embedded inside. If I spot the event that should turn off automatic scrolling I just set a flag and stop scrolling view if that flag is set.
Everything is implemented inside tableController class. Here are parts of three crucial methods.
bool tableController::eventFilter(QObject* object, QEvent* event)
{
switch (event->type())
{
case QEvent::KeyPress:
case QEvent::KeyRelease:
case QEvent::Wheel:
case QEvent::MouseButtonDblClick:
case QEvent::MouseButtonPress:
case QEvent::MouseButtonRelease:
_autoScrollEnabled = false;
default:
break;
}
return QObject::eventFilter(object, event);
}
void tableController::changeFile(int idx)
{
[...]
if (_autoScrollEnabled)
{
QTableWidgetItem* s = _table.item(_engine.getLastProcessed(), 1);
_table.scrollToItem(s);
}
[...]
}
void tableController::tableController()
{
[...]
_autoScrollEnabled = true;
_table.installEventFilter(this);
_table.verticalTableScrollbar()->installEventFilter(this);
[...]
}
Thanks for all the help. I hope somebody will find it useful :)
Subclass QTableWidget and overload its wheelEvent. You can use the parameters of the supplied QWheelEvent object in order to determine if the user scrolled up or down.
Then use a simple boolean flag which is set (or reset) in your wheelEvent override. The method which is responsible for calling scrollToBottom() should then consider this boolean flag.
You will have to find a way to figure out when to set or reset that flag, e.g. always set it when the user scrolls up and reset it when the user scrolls down and the currently displayed area is at the bottom.
connect(_table->view()->verticalScrollBar(), &QAbstractSlider::actionTriggered, this, [this](int) {
_autoScrollEnabled = false;
});
I have a simple list and a background refresh protocol.
When the list is scrolled down, the refresh scrolls it back to the top. I want to stop this.
I have tried catching the COLLECTION_CHANGE event and
validateNow(); // try to get the component to reset to the new data
list.ensureIndexIsVisible(previousIndex); // actually, I search for the previous data id in the IList, but that's not important
This fails because the list resets itself after the change (in DataGroup.commitProperties).
I hate to use a Timer, ENTER_FRAME, or callLater(), but I cannot seem to figure out a way.
The only other alternatives I can see is sub-classing the List so it can catch the dataProviderChanged event the DataGroup in the skin is throwing.
Any ideas?
Actually MUCH better solution to this is to extend DataGroup. You need to override this.
All the solutions here create a flicker as the scrollbar gets resetted to 0 and the it's set back to the previous value. That looks wrong. This solution works without any flicker and the best of all, you just change DataGroup to FixedDataGroup in your code and it works, no other changes in code are needed ;).
Enjoy guys.
public class FixedDataGroup extends spark.components.DataGroup
{
private var _dataProviderChanged:Boolean;
private var _lastScrollPosition:Number = 0;
public function FixedDataGroup()
{
super();
}
override public function set dataProvider(value:IList):void
{
if ( this.dataProvider != null && value != this.dataProvider )
{
dataProvider.removeEventListener(CollectionEvent.COLLECTION_CHANGE, onDataProviderChanged);
}
super.dataProvider = value;
if ( value != null )
{
value.addEventListener(CollectionEvent.COLLECTION_CHANGE, onDataProviderChanged);
}
}
override protected function commitProperties():void
{
var lastScrollPosition:Number = _lastScrollPosition;
super.commitProperties();
if ( _dataProviderChanged )
{
verticalScrollPosition = lastScrollPosition;
}
}
private function onDataProviderChanged(e:CollectionEvent):void
{
_dataProviderChanged = true;
invalidateProperties();
}
override public function set verticalScrollPosition(value:Number):void
{
super.verticalScrollPosition = value;
_lastScrollPosition = value;
}
}
I ll try to explain my approach...If you are still unsure let me know and I ll give you the source code as well.
1) Create a variable to store the current scroll position of the viewport.
2) Add Event listener for Event.CHANGE and MouseEvent.MOUSE_WHEEL on the scroller and update the variable created in step 1 with the current scroll position;
3) Add a event listener on your viewport for FlexEvent.UpdateComplete and set the scroll position to the variable stored.
In a nutshell, what we are doing is to have the scroll position stored in variable every time user interacts with it and when our viewport is updated (due to dataprovider change) we just set the scroll position we have stored previously in the variable.
I have faced this problem before and solved it by using a data proxy pattern with a matcher. Write a matcher for your collection that supports your list by updating only changed objects and by updating only attributes for existing objects. The goal is to avoid creation of new objects when your data source refreshes.
When you have new data for the list (after a refresh), loop through your list of new data objects, copying attributes from these objects into the objects in the collection supporting your list. Typically you will match the objects based on id. Any objects in the new list that did not exist in the old one get added. Your scroll position will normally not change and any selections are usually kept.
Here is an example.
for each(newObject:Object in newArrayValues){
var found:Boolean = false;
for each(oldObject:Object in oldArrayValues){
if(oldObject.id == newObject.id){
found = true;
oldObject.myAttribute = newObject.myAttribute;
oldObject.myAttribute2 = newObject.myAttribute2;
}
}
if(!found){
oldArrayValues.addItem(newObject);
}
}
My solution for this problem was targeting a specific situation, but it has the advantage of being very simple so perhaps you can draw something that fits your needs from it. Since I don't know exactly what issue you're trying to solve I'll give you a description of mine:
I had a List that was progressively loading data from the server. When the user scrolled down and the next batch of items would be added to the dataprovider, the scrollposition would jump back to the start.
The solution for this was as simple as stopping the propagation of the COLLECTION_CHANGE event so that the List wouldn't catch it.
myDataProvider.addEventListener(
CollectionEvent.COLLECTION_CHANGE, preventRefresh
);
private function preventRefresh(event:CollectionEvent):void {
event.stopImmediatePropagation();
}
You have to know that this effectively prevents a redraw of the List component, hence any added items would not be shown. This was not an issue for me since the items would be added at the end of the List (outside the viewport) and when the user would scroll, the List would automatically be redrawn and the new items would be displayed. Perhaps in your situation you can force the redraw if need be.
When all items had been loaded I could then remove the event listener and return to the normal behavior of the List component.
I am using view stack...so when view change like when we move from one page to another hide event is dispatched.So i am saving the information of last page in hide event before i go to next page.but thing is that if i change nothing still change on view hide event is invoked nd call go to backend...i just want do call only if sumthing change in the view..like sum text value...So i have two options
use event listener on each component if sumthing change its make the flag true...nd hide event check, if flag is true send call to backend.
event listener at container level ..if sumthing change in child componenet through bubbling container knows if sum event is dispatched.nd makes the flag true.
I have doubt with container...
Can i use container, and how?
Reason why I can't use container?
What are the pros and cons either way?
I would recommend using a dataProvider with the ability to compare them. For instance, if you are changing things with textinputs, you could basically do something like this:
[Bindable]
private var myDataProvider:Object = new Object();
private function creationCompleteHandler():void {
myDataProvider.updated = false;
myDataProvider.defaultValue = 'default';
myDataProvider.defaultValueTwo = 'default';
}
etc.
Then, in your mxml, you can have something like this:
<mx:TextInput id="myText" text="{myDataProvider.defaultValue}" change="myDataProvider.defaultValue=myText.text; myDataProvider.updated=true;" />
Lastly, in your hide event, you can do the following:
private function hideEventHandler( event:Event ):void {
if( myDataProvider.updated ){
// Call your RemoteServices (or w/e) to update the information
}
}
This way, when anything changes, you can update your dataProvider and have access to the new information each time.
Hope this helps!
I've used an approach similar to your first option in a couple of my past projects. In the change event for each of my form's controls I make a call to a small function that just sets a changesMade flag to true in my model. When the user tries to navigate away from my form, I check the changesMade flag to see if I need to save the info.
Data models are your friend!
If you get in the habit of creating strongly typed data models out of your loaded data, questions like this become very basic.
I always have a key binding set to generate a code snipit similar to this...
private var _foo:String;
public function get foo():String
{
return _foo;
}
public function set foo(value:String):void
{
if(_foo == value)
return;
var oldVal:String = _foo;
_foo = value;
this.invalidateProperty("foo", oldVal, value);
}
If your data used getters/setters like this, it would be very easy to validate a change on the model level, cutting the view out of the process entirely.
I'm using MATE on an Adobe Flex project for MVC. On one of our pages, we have a dialog window that is presented to the user that displays them information that comes from RPC. The pages where this dialog pops up is unrelated to the data being displayed so this is a separate model. How do I create a MATE mapping file that will create the dialog window, make it visible to the user, and then inject in data from a model?
Thanks for reading.
Seems like you found an approach, but if you are interested in another idea, there is a really good thread on the Mate forums about how to approach popups in Mate. It includes some example code and discusses the best practices involved and why certain choices are being made:
Converting app with popups to Mate << Mate Forums
If I understand you correctly, here is some code to do what you need (adapted from that thread). It injects the result of an RPC call into the view (keeping the map agnostic of how the view displays that data), and the view will create a popup whenever there is data, and remove the popup whenever there is no data. The thread has further explanation of most of this code.
EventMap:
<Injectors target="{PopupParentView}">
<PropertyInjector destinationKey="rpcData"
source="{FooManager}" sourceKey="rpcData" />
</Injectors>
PopupParentView:
...
private var popup : UIComponent;
private var rpcData : Object;
private function onPreinitialize( event : Event ) : void {
BindingUtils.bindSetter(rpcDataChanged, this, "rpcData");
}
private function rpcDataChanged( value : Object ) : void {
invalidateProperties();
}
override protected function commitProperties( ) : void {
// two mutually exclusive branches: either the property can be interpreted as "show the popup"
// and the popup doesn't exist, or we shouldn't show the popup, but it does exist. all other
if ( rpcData != null && popup == null ) {
popup = PopUpManager.createPopUp(...);
} else if ( rpcData == null && popup != null ) {
// make sure to set the popup property to null
PopUpManager.removePopUp(popup);
popup = null;
}
}
</Script>
...
I've done a lot of C# programming with both Winforms and WPF. I'm working on a Flex/Air app now for cross platform support. But this is my first flex project, so I'm learning as I go.
I've got a window that I want to popup, that the user will fill out a form, then hit OK or CANCEL. I set it up the same way I would've in C#, but it doesn't work, and I can't really see a way to make it do what I want.
EDIT:
So I'm trying events now, the events just don't seem to be handled...
EDIT again:
Oh, It's because the popup manager seems to create a new instance of the Form object, rather than using the one I created already.
so in the showWindow method, I put in this code rather than the popup manager:
parent.addChild(this);
then I remove it when I close it. The only problem is, it doesn't disable the rest of the parent like the popup manager does. Any suggestions on that?
PARENT:
private function btnAdd_Clicked():void
{
var form:Form = new Form();
form.addEventListener(CloseEvent.CLOSE, onFormClosed, false, 0, true);
recipeForm.showWindow(this);
}
private function onFormClosed(e:CloseEvent):void
{
//none of these Alerts are ever shown. I also tried breakpoints in debug to try an follow the code, with no luck
Alert.show("Closed");
if(e.detail == Alert.OK)
{
Alert.show("OK");
}
else if(e.detail == Alert.CANCEL)
{
Alert.show("Cancel");
}
}
CHILD:
private function btnCancel_Clicked():void
{
okClicked = false;
closeWindow();
}
public function closeWindow():void
{
var e:CloseEvent = new CloseEvent(CloseEvent.CLOSE);
e.detail = okClicked ? Alert.OK : Alert.CANCEL;
dispatchEvent(e);
PopUpManager.removePopUp(this);
}
public function showWindow(parent:WindowedApplication):void
{
var window:IFlexDisplayObject = PopUpManager.createPopUp(parent, RecipeForm, true);
PopUpManager.centerPopUp(window);
}
You can do this at least two different ways:
FIRST WAY: Using events
Let your Form class dispatch an event when either of the buttons is clicked. After Form is instantiated from the parent view, add an eventListener for the event(s) it's known to dispatch. When the Form dispatches the event, the eventListener will be invoked. You can even reuse Flex's CloseEvent and set the "detail" property to either Alert.OK or Alert.CANCEL before dispatching it.
In Form:
var e:CloseEvent = new CloseEvent(CloseEvent.CLOSE);
e.detail = okClicked ? Alert.OK : Alert.CANCEL;
dispatchEvent(e);
In parent:
var f:Form = new Form();
f.addEventListener(CloseEvent.CLOSE, onClose, false, 0, true);
...
private function onClose(e:CloseEvent):void
{
if (e.detail == Alert.OK)
// do something
else if (e.detail == Alert.CANCEL)
// do something else
}
SECOND WAY: Using callbacks
Add a public var of type "Function" to your Form class and supply a callback function from the parent. This does basically the same thing as #1 except with little less abstraction / indirection.
I would recommend #1 since the event model in Flex is pretty well-conceived and more flexible than the callback.
In Form:
var e:CloseEvent = new CloseEvent(CloseEvent.CLOSE);
e.detail = okClicked ? Alert.OK : Alert.CANCEL;
dispatchEvent(e);
In parent:
var f:Form = new Form();
f.addEventListener(CloseEvent.CLOSE, onClose, false, 0, true);
...
private function onClose(e:CloseEvent):void
{
if (e.detail == Alert.OK)
// do something
else if (e.detail == Alert.CANCEL)
// do something else
}
Not sure if this is still an open issue. I ran into this very same problem and I think I figured out what is wrong. At least I did for my problem.
I implemented things exactly as you did. I also have the close attribute set to closeWindow (I'm using a TitleWindow for my dialog).
So when the window is closed via the X at the top, it will call closeWindow, also if you click on the Cancel button, it will also call closeWindow.
The problem for me was that clicking cancel, dispatches a CloseEvent which seems to be caught by a Listener which calls closeWindow again (possibly via the close attribute which probably creates its own internal listener). I'm not sure if its an infinite loop but Flex does not like this.
My solution was to create two functions, one for the X close window to call and one for the Cancel button to dispatch a CloseEvent of its own. This seemed to work for me. Hope it helps you.