Flex :: Get The Visible Items On A Spark List With Virtual Layout?
Apr 12, 2010
I have:
an ArrayCollection of Numbers;
a List using the above ArrayCollection as it's dataprovider, and virtualLayout=true;
a custom ItemRenderer that shows a label with:
a) the number
b) an y position depending on the number AND the highest number visible
In another words, if I have 10 numbers in the AC, and only 5 appear on the screen, the y position of those 5 will depend on the value of the maximum number for those 5. When the user scrolls, of course those 5 elements change so the position of the label in item renderers will change.
1) How can I get the list of items that are "currently" visible?
2) Which event/method to override will help me know that the List was scrolled/the visible items changed?
I'm creating a facebook application in flex. I'm actually working on the friends component that shows your friends who are using the application. now, each friend has a profile image.
I created the component using a s:List element.
In the Skin Class of the element i configured the requestedColumnCount to 3, which means it shows 3 friends. i added buttons to scroll left and right in the list.
Whenever I scroll to see a different friend, for a half of a second i see no image because the List component is loading the image in order to view it.
is there a way to make the list preload all the elements so i won't have this kind of problem ?
I have a s:List where I've defined my own itemRenderer, and would like to insert a horizontal line separating items, similar to the way the mx:LinkBar works. I don't want to have a line at the top or bottom of the list, so I can't just include an upper or lower border in the itemRenderer. I was hoping the itemRenderer could be made aware of its index in the list, but I don't see how.
[code]I want to extend the list with hyperlinks. For example in every node I should have an href attribute also. Then I need to redirect users to the selected item. I know Flash has the URLRequest class. The little problem I have now is to get the selected item. It propably is because of the dataprovider is xml and I haven't done the correct casting.
I have a Spark.List with several items ("folders") each containing an ArrayList of files inside, when I select one of these "folders" it should display the list of "files" on another Spark.List. Its working right now by doing this: private function onFolderChange (event:*):void { var list:List = event.currentTarget as List; if (list.selectedIndex != -1) { currentFolder = null; currentFolder = list.selectedItem; fileListDataProvider = currentFolder.files; fileList.selectedIndex = -1; }}
The problem is that when the "file" thumbnails cover more then the List viewport and a scroll is needed sometimes by changing from a "folder" to another "folder" the file List loses files. For example lets say there is a "Folder 1" with 30 "files" in it (10 visible and 20 hidden by the scroller) and "Folder 2" has 5 "files" (all visible), if I switch back and forth between "folders" sometimes it will display everything right. Sometimes it will display a scroll on "Folder 2" when there is no need and sometimes it will only display a few (5 or 10) "files" in "Folder 1" even though it has 30. Something is wrong with the fileList, its updating its items but not really updating well. I've tried setting the itemRenderer to null and reapplying, setting the dataProvider to null and reapplying, doing validateNow().
I have a custom component, containing a List displaying items from an XMLListCollection:
[Code]....
Also if I click twice, only 1 mouse click will cause my custom event to be dispatched (because obviously there is no change between the items). how to make my List only react to mouse clicks? UPDATE: Yes, I've tried using "change" event for the List before, but then I have the problem that it is fired, even if the List scrollbar is clicked.
I am trying to create a generic List, where I can pass the layout & item renderer as parameters.Since it is not possible to pass parameters to a MXML component's Constructor, I figured I should create my List in Actionscript.
[Code]...
I would prefer to have the List in MXML (because It will be easier using states later), but If I am forced to use pure Actionscript so I can instantiate it and pass in parameters, any help would go a long way.
In a flex project that I have that is designed to scale 100% to the web window, I have a spark list. And I have a simple itemrenderer that takes the data and displays a name, and a message. Just think of it like a simple instant messenger display. The problem is that for my msg_txt label I want to give it a width thats the width of the parent list thats holding it.I tried turning the horizontalScrollPolicy to off, also tried width="this.parent.parent.width}" (as well as this.parent.width) for the spark label inside the item renderer. and in the label i tried some things like left="0" right="0" maxWidth="{this.width}" but nothing really does the trick.How can I make this label have a max width of the list thats holding it, AND make sure it resizes if the size of the browser changes and the list size changes?heres the list:
I've created a skin that allows me to have two labels on a spark button, but the button text won't center vertically. It stays at the top of the button no matter what settings I give it. The icon in the skin DOES however, center vertically. This is the skin:
I've got the following situation, where I have an outer Vbox that is set at a fixed width, and then inside it there is a header made from an HBox and a content area (Canvas) that is much wider than the enclosing VBox (and therefore requires scrollbars on the outer VBox to see it all).
I would like to set the width of the header to fill the entire width of the outer container, but only the visible part, and to remain fixed so that when I scroll to view the content, the header doesn't move.
I'm trying to animate a list as I delete the top row. All the examples I can find use itemsChangeEffect to bind to the effect, but this property exists only in MX lists, not spark lists.
Any idea how I can get the same effect done in Spark Lists?
I'm trying to remove the top most item in the list with a slight fade out effect before the rest of the items move up to replace the gap.
I'm using flex 4.1 to write an application. i read in the documents that has the rowCount property to set how many items to display. the does not have that property. how can I limit the list to display 3 items ?
The 'recommendations' dataProvider is an ArrayCollection of String, which are generally sentences about as long as this one. By setting the variableRowHeight and wordWrap properties as shown, if a sentence is too long to fit on a single line, everything works fine- the row expands and the messages show on two lines, or occasionally three.
The space allocated for this panel within the entire canvas means if the total text size of 'recommendations' exceeds six lines, I need for the entire list scroll. This is also working just fine. The trouble is when using the mouse wheel to do the scrolling- Flex scrolls both the entire list and the single item where the mouse is hovering. Often this results in only the second half of a sentence being visible. Non-programmer friends I have asked to look at this noticed this, and tell me it as a problem. If a user does not notice the dual scrolling, and sees only a fragment of a sentence, it will be perceived as an error in the application.
I created a custom layout for a list, to be used on a mobile (android). I used this as example : [URL], using virtualization. Now the problem I have is with scrolling : when scrolling to the bottom of the list, there seems to be always a "bounce back", as if the list would have reached and as if the bounce/pull effect is taking place. But in fact the list has not reached the end at all, in fact I can not even scroll to the last element in the list. When going back from bottom to top, there's no problem at all.
I trace the top and bottom of the Scrolling Rectangle (Rectangle.getScrollRect) and there I can see that when scrolling down, the top and bottom parameters increase, but when releasing the touchscreen, all of a sudden the parameters decrease again with a certain amount, and so never reaching the end of the list. All my code is available on google project hosting : [URL]
I have a DataGrid where some number of the columns can have a labelFunction. The nature of the labelFunction result can change problematically(eg apply formatting,bypass formatting. How do I get the DataGrid to re-render the visible items so that the labelFunction will be run again to get the new data.I've tried the invalidateDisplayList, validateNow, and tried dispatching ResizeEvents on the DataGrid.
I have noticed two differences between spark and mx forms which are causing me some problems. It seems by default the mx forms are arranged to the label is above the form input item. In Spark they are arranged next to each other. Also the label in spark forms are bold by default.For example MX code could be
I have a Spark List with a data provider consisting of a list of filled out form applications. What is the best way to add a button to each List Item (form application)? This button will be named Open and will navigate to the specified form application.
I have a spark list, which is based on a dataProvider. As the application runs, the data in the dataprovider can change, and also the dataProvider can be swapped for a different one
What I need to do is make sure that something is always selected in the list (unless it is empty)
I have two spark lists and want to drag items from one list to the other. When im dragging an item and over the other list item, i want the target item to change the background coloer.Basically instead of showing the black line indicating that I will drop between elements, I want to see the target item highlight.
How do I wordwrap in a spark list w/ an itemrenderer? This posting at[URL] works 100% but when I try to set a separate item renderer, I can't get the word wrapping...instead, I get an ugly horizontal scroll bar. HEre is my mxml:
I would like to add custom right clicks to a number of spark list controls. I have tried the following as an item renderer. (as per the flex 4 cook book). Full Render code here [URL] When I right click on the Spark List I simply get the Adobe Default Context menu. This is the same default behaviour I had before I added any code to this.
how do i code it so that when user tap on item label="Page One" it will navigate to PageOneView.mxml and if it tap on "Page Two" it will go to PageTwoView.mxml and so on.
