How would I display a backgroundImage on a List when the List is empty?
At the moment the list is populated when items are dropped inside after a drag-and-drop but I would prefer a solution that checks for any change to the data to determine if the list is empty.
The List inherits a backgroundImage from its ScrollControlBase but what would be the best way to make it appear when the list is empty and disappear when an item is added.
Any suggestions?
Thanks!
In the past, I've done it with states for a component. Quick and dirty example would be something like this in your custom component:
<mx:List currentState="{(listItemsDataProvider.length > 0) ? 'HasItemsState' : 'NoItemsState'}">
// anything else you need
</mx:List>
and of course creating those states in the component, with the NoItemsStates changing the background image, or if your component is a container, like a Canvas, then you can have the state not display the List at all.
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
<mx:Script>
<![CDATA[
import mx.collections.ArrayCollection;
[Bindable] public var listItems:ArrayCollection = new ArrayCollection();
private function removeAllItemsFromList():void
{
this.listItems.removeAll();
backgroundCheck()
}
private function addItemToList():void
{
this.listItems.addItem({data:null,label:"test"});
backgroundCheck()
}
private function backgroundCheck():void
{
if(this.listItems.length>0)
{
this.myList.setStyle("backgroundImage", null)
}
else
{
this.myList.setStyle("backgroundImage", "me.png")
}
}
]]>
</mx:Script>
<mx:VBox width="100%" height="100%">
<mx:List id="myList" width="100%" height="100%" backgroundImage="me.png" dataProvider="{this.listItems}"/>
<mx:HBox width="100%">
<mx:Button id="addItemButton" click="addItemToList()" label="add item"/>
<mx:Button id="removeItemsButton" click="removeAllItemsFromList()" label="remove all items"/>
</mx:HBox>
</mx:VBox>
</mx:Application>
This is how I would approach it, checking the dataProvider length. In your case you'd do so when the drop is complete.
You could extend the List control and override updateDisplayList(). Draw the backgroundImage if dataProvider.length == 0 else call super.updateDisplayList() to get normal List behavior. This will make the new List control easy to reuse if you need to.
Use the same property, set the image to null when you have some data. You may take a look at custom ItemRenderers as well.
Related
I have a List which has TextInput as itemRenderers for all its items. Upon application launch the items are rendered in the TextInputs correctly. The data is being populated from an Array of Objects.
What I want is, after the data has been populated in the ItemRenderers, I want to have an additional item renderer (TextInput of course)...so that if the user wants to enter another item, he can put it in the additional textInput.
And I also want to add the additional itemRenderer each time the user has added a new item and taps ENTER on the newly added item.
Below is my itemRenderer, there is the clearTxt_enterHandler handler..but I wonder how to add another itemRenderer upon "Enter".
Can somebody guide me with this?
Thx
<?xml version="1.0" encoding="utf-8"?>
<s:ItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx"
autoDrawBackground="true" xmlns:components="components.*" width="100%">
<s:layout>
<s:HorizontalLayout/>
</s:layout>
<fx:Script>http://stackoverflow.com/questions/4199373/flex-4-is-a-good-practice-store-the-loaded-bitmapdata-in-a-value-object-and-then
<![CDATA[
import mx.events.FlexEvent;
import skins.ClearableTextInputSkin;
override public function set data( value:Object ) : void {
super.data = value;
//clearTxt.text = value.label;
}
protected function clearTxt_enterHandler(event:FlexEvent):void
{
trace("On Enter");
}
]]>
</fx:Script>
<components:ClearableTextInput text="{data.label}" id="clearTxt"
skinClass="skins.ClearableTextInputSkin" enter="clearTxt_enterHandler(event)" left="10" top="36" width="220" />
</s:ItemRenderer>
And this is my list that comes from the main application:
<s:List id="myList" itemRenderer="renderers.TextInputRenderer" dataProvider="{xxx}" width="100%">
<s:layout>
<s:TileLayout requestedRowCount="2"columnAlign="justifyUsingWidth"/>
</s:layout>
</s:List>
From the ItemRenderer, dispatch an Event to request the new ItemRenderer. Be sure to make it bubbling, so that it goes all the way up to the List that owns the ItemRenderer.
protected function clearTxt_enterHandler(event:FlexEvent):void
{
dispatchEvent(new Event("myCustomRequestEvent", true));
//replace with a real custom Event; this is for brevity
}
Listen for that event on the List component and in the handler just add a new element to its dataprovider (probably with an empty label).
myList.addEventListener("myCustomRequestEvent", addRow);
private function addRow(event:Event):void {
myList.dataProvider.addItem({label: null});
//replace anonymous object with your class
}
This will add a new item to the List. In your case you may have to bind requestRowCount to the number of items in the List, so that it will grow when you add the items.
<s:VerticalLayout requestedRowCount="{myList.dataprovider.length}" />
BTW: why are you using TileLayout? If what you want is two input boxes per item, you should put two TextInputs in one ItemRenderer and use VerticalLayout. It will make your life a lot easier.
I am using a Repeater in an Accordian which does not appear to see a single element in userArray. If I add another entry to userArray then the Repeater works fine.
Thoughts??
private function currUsersServiceHandler(event:ResultEvent):void{
if (event.result.currentUsers != null)
{
if (event.result.currentUsers.user is ArrayCollection) // if more than one elements are present
{
usersArray = event.result.currentUsers.user;
}
else if (event.result.currentUsers is ObjectProxy)
{ //FIXIT usersArray populate by following line has some issue
usersArray = new ArrayCollection(ArrayUtil.toArray(event.result.currentUsers));
}
}
}
<mx:HTTPService id="currUsersService" url="currUsers.xml" result="currUsersServiceHandler(event)"/>
<mx:Accordion includeIn="UserList" x="10" y="10" width="554" height="242" >
<mx:Repeater id="rep" dataProvider="{usersArray}">
<mx:Canvas width="100%" height="100%" label="{rep.currentItem.firstName}" >
<mx:HBox>
<s:Label text="{rep.currentItem.firstName}"/>
<s:Label text="{rep.currentItem.lastName}"/>
<mx:/HBox>
</mx:Canvas>
</mx:Repeater>
</mx:Accordian>
Edit:
There is another thing I have just noticed i.e. that the accordian does show a single tab (when Array has a single element) but it's not labeled with the first name which I am setting. If I enter another user, two tabs appear and both are labeled with names I am setting. The first tab appears labeled too then.
It makes no sense to me that this would not work with 1 item in the dataProvider, but would work with two.
That said, tThis approach strikes me as convoluted and I tend to stay away from using repeaters at all. I would suggest a different approach.
First create a component to display your data. You can reuse you're existing code. Conceptually something like this:
<mx:Canvas width="100%" height="100%" >
<mx:Script><[[
public var user : Object;
]]></mx:Script>
<mx:HBox>
<s:Label text="{user.firstName}"/>
<s:Label text="{user.lastName}"/>
<mx:/HBox>
</mx:Canvas>
Then in your original component create the new instance of the component in ActionScript:
for each(var myUserObject : Object in usersArray){
var newUserDisplayObject : UserDisplayObject = new UserDisplayObject();
newUserDisplayObject.user = myUserObject;
newUserDisplayObject.label = myUserObject.firstName
accordian.addChild(newUserDisplayObject);
}
I'm displaying a list of buttons, some of which might be disabled. I need to show a tooltip on the disabled buttons with an explanation of why it's disabled, but it seems I can't disable the button without disabling the tooltip. Is there a simple way around this?
Wrap the Button in a Group, and apply the toolTip to the group instead.
<s:Group toolTip="My toolTip">
<s:Button enabled="false"/>
</s:Group>
It's a bit ugly, but it works.
One way to do this is to override the enabled getter and setter to do what you want. So in my case, I still wanted most mouse events to fire, just not the click event.
<?xml version="1.0" encoding="utf-8"?>
<s:Button buttonMode="true" click="handleClick(event)" xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:mx="library://ns.adobe.com/flex/mx" xmlns:s="library://ns.adobe.com/flex/spark">
<fx:Script>
<![CDATA[
public var data:Object;
private var _enabled:Boolean = true;
public override function get enabled():Boolean
{
return _enabled;
}
public override function set enabled(value:Boolean):void
{
_enabled = value;
invalidateDisplayList();
dispatchEvent(new Event("enabledChanged"));
invalidateSkinState();
}
protected function handleClick(event:MouseEvent):void
{
if (!_enabled)
{
event.stopPropagation();
}
}
]]>
</fx:Script>
</s:Button>
Since mouse events now fire, the tooltips work again.
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.managers.ToolTipManager;
import mx.controls.ToolTip;
private var tooltip:ToolTip;
private var p:Point;
private function whyDisable():void
{
//calculate the button position , so that roll over shows the tooltip
p=new Point();
p=localToGlobal(new Point(btn.x,btn.y));
if(btn.enabled==false)
tooltip = ToolTipManager.createToolTip('Button is disabled',p.x+(btn.width/2),p.y-20,'errorTipAbove') as ToolTip;
else
tooltip=ToolTipManager.createToolTip('Button is enabled',p.x+(btn.width/2),p.y-20,'errorTipAbove') as ToolTip;
}
]]>
</mx:Script>
<mx:VBox height="100%" width="100%" horizontalAlign="center" verticalAlign="middle">
<mx:Button id="btn" label="Show Tooltip" buttonDown="trace('ankur')" autoRepeat="true" enabled="true" rollOver="whyDisable();" rollOut="{ToolTipManager.destroyToolTip(tooltip);}"/>
</mx:VBox>
</mx:Application>
Hi, this application works on the disabled button,I used ToolTipManager to do this,
i hope this works for you
have a gr8 time
Ankur Sharma
The best choice for me was to put a void label around and in front of the element. Then, if necessary, I set the element to disable and the tooltip works in the label. If not, I put sent the label to back. It works pretty well.
if (new MainListsAdmin(this.mainApp).temInvestimentoComAqueleTipo(t)) {
deletarGroupInto.setTooltip(new Tooltip("Há investimentos vinculados a Tipo de Investimento.\nDeleção bloqueada."));
this.deletarButton.setDisable(true);
}else{
deletarGroupInto.toBack();
}
You will need to use the ToolTipManager class to create and destroy the tool tips manually.
This article should give you all the info you need to accomplish this:
http://help.adobe.com/en_US/flex/using/WS2db454920e96a9e51e63e3d11c0bf60d65-7ff6.html
I'm trying componentize one of the pieces of UI in an AIR application that I'm developing in Flex. In this example, I want to display file information on a single line (which has an icon, some text/link and the size).
My code looks like this (component is called FileDisplay):
<?xml version="1.0" encoding="utf-8"?>
<mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
public function set iconType(source:String):void {
this.ficon.source = source;
}
public function set fileName(name:String):void {
this.fname.htmlText = name;
}
public function set fileSize(size:String):void {
this.fsize.text = size;
}
]]>
</mx:Script>
<mx:Image id="ficon" />
<mx:Label id="fname" left="20" right="30" text="Filename" />
<mx:Label id="fsize" right="0" text="0 K" />
</mx:Canvas>
When I'm using this component in my main application, the actionscript looks like:
for each (var file:XML in result.files) {
var fd:FileDisplay = new FileDisplay();
fd.fileName = ''+file.name+'';
fd.iconType = getFileTypeIcon(file.name);
fd.fileSize = getFileSizeString(file.size);
this.file_list.addChild(fd);
}
However, when I do this, I get an error: Error #1009: Cannot access a property or method of a null object reference. This is because the child components of the FileDisplay are null (or at least they show up that way in the debugger).
Does anyone know if there's a way around this? Am I supposed to be waiting for events indicating the child components were created? Is there a more common pattern that solves this problem?
For now I can manually do everything in ActionScript in my main app (create a Canvas and add children to it) but I would appreciate any insight on how to separate the code more cleanly.
Bindable to the rescue:
<?xml version="1.0" encoding="utf-8"?>
<mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
[Bindable]
public var iconType:String;
[Bindable]
public var fileName:String = "Filename";
[Bindable]
public var fileSize:String = "0 K";
]]>
</mx:Script>
<mx:Image id="ficon" source="{iconType}"/>
<mx:Label id="fname" left="20" right="30" text="{fileName}" />
<mx:Label id="fsize" right="0" text="{fileSize}" />
</mx:Canvas>
the values will be automatically updated when the components are created.
The subcomponents haven't been loaded yet.
Read this: http://livedocs.adobe.com/flex/3/html/help.html?content=ascomponents_advanced_2.html#203434.
Then, when like me, you don't understand it (and it's not reliable), listen for the FlexEvent.CREATION_COMPLETE within FileDisplay, and apply your child component properties there.
Or better yet, create the three children programmatically in the "createChildren" function, and apply the settings there.
Both of these methods assume that you're setting filename, icontype, and filesize as local members before applying them to the children components, which you should be doing regardless.
What is the parent component that holds the FileDisplay component? If you're sure that the error is coming from the fact that the child components of FileDisplay aren't being instantiated then you might want to look at the creationPolicy attribute and make sure it's set to ContainerCreationPolicy.ALL on that parent component.
=Ryan
In addition to setting the CreationPolicy to all, you need to add the DisplayObject to the stage via addChild. The children of FileDisplay are not created until you add it is added to the stage. So do:
for each (var file:XML in result.files) {
var fd:FileDisplay = new FileDisplay();
this.file_list.addChild(fd);
fd.fileName = ''+file.name+'';
fd.iconType = getFileTypeIcon(file.name);
fd.fileSize = getFileSizeString(file.size);
}
I'm going spare trying to figure out the "correct" way to embed a ComboBox inside a Flex (3.4) DataGrid. By Rights (e.g. according to this page http://blog.flexmonkeypatches.com/2008/02/18/simple-datagrid-combobox-as-item-editor-example/) it should be easy, but I can't for the life of me make this work.
The difference I have to the example linked above is that my display value (what the user sees) is different to the id value I want to select on and store in my data provider.
So what I have is:
<mx:DataGridColumn headerText="Type" width="200" dataField="TransactionTypeID" editorDataField="value" textAlign="center" editable="true" rendererIsEditor="true">
<mx:itemRenderer>
<mx:Component>
<mx:ComboBox dataProvider="{parentDocument.transactionTypesData}"/>
</mx:Component>
</mx:itemRenderer>
</mx:DataGridColumn>
Where transactionTypesData has both 'data' and 'label' fields (as per what the ComboBox - why on earth it doesn't provide both a labelField and idField I'll never know).
Anyway, the above MXML code doesn't work in two ways:
The combo box does not show up with any selected item.
After selecting an item, it does not store back that selected item to the datastore.
So, has anyone got a similar situation working?
While Jeff's answer is a partial answer for one approach for this (see http://flex.gunua.com/?p=119 for a complete example of this being used to good effect), it isn't as general as I wanted.
Thankfully, I finally found some great help on Experts Exchange (the answers by hobbit72) describes how to create a custom component that works in a grid as a ItemRenderer.
I've extended that code to also support using the combo box as an ItemEditor as well. The full component is as follows:
<?xml version="1.0" encoding="utf-8"?>
<mx:ComboBox
xmlns:mx="http://www.adobe.com/2006/mxml"
dataChange="setSelected()"
change="onSelectionChange(event)"
focusEnabled="true">
<mx:Script>
<![CDATA[
import mx.events.DataGridEvent;
import mx.events.ListEvent;
import mx.controls.dataGridClasses.DataGridListData;
private var _ownerData:Object;
private var _lookupField:String = "value";
// When using this component as an itemEditor rather than an itemRenderer
// then set ' editorDataField="selectedItemKey"' on the column to
// ensure that changes to the ComboBox are propogated.
[Bindable] public var selectedItemKey:Object;
public function set lookupField (value:String) : void {
if(value) {
_lookupField = value;
setSelected();
}
}
override public function set data (value:Object) : void {
if(value) {
_ownerData = value;
setSelected();
}
}
override public function get data() : Object {
return _ownerData;
}
private function setSelected() : void {
if (dataProvider && _ownerData) {
var col:DataGridListData = DataGridListData(listData);
for each (var dp:Object in dataProvider) {
if (dp[_lookupField] == _ownerData[col.dataField]) {
selectedItem = dp;
selectedItemKey = _ownerData[col.dataField];
return;
}
}
}
selectedItem = null;
}
private function onSelectionChange (e:ListEvent) : void {
if (selectedItem && _ownerData) {
var col:DataGridListData = DataGridListData(listData);
_ownerData[col.dataField] = selectedItem[_lookupField];
selectedItemKey = selectedItem[_lookupField];
}
}
]]>
</mx:Script>
</mx:ComboBox>
Using this component is straight forward. As an ItemRenderer:
<mx:DataGridColumn headerText="Child" dataField="PersonID" editable="false" textAlign="center">
<mx:itemRenderer>
<mx:Component>
<fx:GridComboBox dataProvider="{parentDocument.childrenData}" labelField="Name" lookupField="PersonID" change="dispatchEvent(new mx.events.DataGridEvent(mx.events.DataGridEvent.ITEM_FOCUS_OUT, true, true))"/>
</mx:Component>
</mx:itemRenderer>
</mx:DataGridColumn>
Using this component is straight forward. And as an ItemEditor:
<mx:DataGridColumn labelFunction="lookupChildName" headerText="Child" dataField="PersonID" editable="true" editorDataField="selectedItemKey">
<mx:itemEditor>
<mx:Component>
<fx:GridComboBox dataProvider="{parentDocument.childrenData}" labelField="Name" lookupField="PersonID" change="dispatchEvent(new mx.events.DataGridEvent(mx.events.DataGridEvent.ITEM_FOCUS_OUT, true, true))"/>
</mx:Component>
</mx:itemEditor>
</mx:DataGridColumn>
Note that when using it as an ItemEditor, a custom labelFunction (that looks up the Name from the PersonID in my case) must be used, otherwise you only see the key in the grid when the field isn't being edited (not a problem if your keys/values are the same).
Note that in my case, I wanted the item focus out event to propogate up to provide immediate feedback to the user (my DataGrid has itemFocusOut="handleChange()"), hence the change event creating an ITEM_FOCUS_OUT event.
Note that there are probably simpler ways to have a ComboBox as an ItemEditor when you don't mind the ComboBox only shown when the user clicks on the cell to edit. The approach I wanted was a generic way to show a combo box in a DataGrid for all rows, and being editable and with decent event propogation.
The easiest way to add itemRenderers to DataGrids is to make a custom MXML component. In your case make a canvas, HBox, or VBox as the custom component and add the combobox as a child.Set the dataProvider on the dataGrid itself and assign the itemRenderer to the column, and then override the set data function of the itemRenderer to access all data from the given data provider for that instance as seen below:
<mx:HBox xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
override public function set data(value:Object):void{
trace(value.data);
trace(value.name);
}
]]>
</mx:Script>
<mx:ComboBox width="100%" height="100%" id="myComboBox"/>
</mx:HBox>
This method will be called for each instance of the itemRenderer
In my case I used a spark datagrid where one of the columns has an ItemRenderer that utilises a DropDownListBox. My problem was that when my item list change, the DropDownLists doesn't get updated with the new dataProvider. To solve this, I had to pass the dataProvider for the DropDownListBox as part of the data (of the ItemRenderer), and then by overriding the setter of the data to just assign the DropDownlListBox's dataProvider. Probably a bit of overhead, but if someone have a better solution, please let me know:
<s:GridItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx">
<fx:Script>
<![CDATA[
override public function set data(v : Object) : void {
super.data = v;
if (v == null)
return;
dropDown.dataProvider = data.dataProvider;
}
]]>
</fx:Script>
<s:DropDownList id="dropDown" width="100%" height="100%" dataProvider="{data.dataProvider}" labelField="name"/>