I have a weird problem with verticalScrollPosition in Flex.
I have a content Canvas and a wrapper Canvas. The content is large (5000px X 5000px), the wrapper is 800px X 800px.
public var wrapper:Canvas = new Canvas();
public var content:Canvas = new Canvas();
wrapper.addChild(content);
application.addChild(wrapper);
I would like to set the wrapper's scrollbar position dynamically anytime. I can do it by calling its properties:
wrapper.verticalScrollPosition = A;
wrapper.horizontalScrollPosition = B;
This is working fine. But! If I set a default scrollbar position when the Canvas is complete:
wrapper.addEventListener(FlexEvent.CREATION_COMPLETE, function(e:FlexEvent):void{
wrapper.verticalScrollPosition = DEFAULT_A;
wrapper.horizontalScrollPosition = DEFAULT_B;
});
I can't set the verticalScrollPosition anymore:
wrapper.verticalScrollPosition = C;
trace(wrapper.verticalScrollPosition); // Outputs: DEFAULT_A
So the problem only exist if I set a default position using 'FlexEvent.CREATION_COMPLETE'.
What am I doing wrong here?
Thanks in advance.
I've found a horrible workaround - I wait 1 microsecond to set the default state:
wrapper.addEventListener(FlexEvent.CREATION_COMPLETE, function(e:FlexEvent):void{
setTimeout(
function():void{wrapper.verticalScrollPosition = DEFAULT_A;},
1
);
});
I think we can agree it's really ugly. How can I make it better?
I've found the problem. I attached the event listener to the child of the wrapper. When I added the listener to the wrapper itself it works.
So lesson I've learnt: always track the topmost ui element's events you have to work with.
Related
I have a spark skinnable component which contains a datagroup with images. The datagroup is scrolled by hovering the mouse over it. Everything works fine except one thing: after I change the datagroup provider, I need to scroll down automatically. The problem is the images are not loaded immediately after I set the provider so (contentHeight - height) does not yet represent the actual maximum scrolling position. Is there an easy way of telling the datagroup to scroll down as its content loads? Because the workaround seems to be not so straightforward.
This is the code for scrolling(thumbnailStrip is my datagroup):
private function thumbnailStrip_mouseMoveHandler(evt:MouseEvent):void {
var fr:Number = (thumbnailStrip.contentHeight - thumbnailStrip.height) / thumbnailStrip.height;
var scroll:Number = fr * evt.stageY - fr * this.y;
var ms:Number = maxScroll();
if(scroll > ms) scroll = ms;
thumbnailStrip.verticalScrollPosition = scroll;
}
private function maxScroll():Number {
return thumbnailStrip.contentHeight - thumbnailStrip.height;
}
Thanks,
Calin
thumbnailStrip.layout.verticalScrollPosition += thumbnailStrip.layout.getVerticalScrollPositionDelta(NavigationUnit.END);
This may have to run a few times to get all the way to the bottom.It's supposed to return the difference between the current scroll position and the "end" of the scroll position. As things load, I'd just keep calling this in a "callLater".
btw, there's a bug for this: http://bugs.adobe.com/jira/browse/SDK-25740 not sure if it's fixed in 4.5, ugly workaround here: http://flexponential.com/2011/02/13/scrolling-to-the-bottom-of-a-spark-list/
I thought I had a handle on AS3, DisplayObjectContainers, etc. but this basic thing is really confusing me: changing the width/height of a sprite does not affect it's visual contents - either graphics drawn within it or any children it may have.
I have searched around and found an Adobe page that represents my own little test code. From that page, I would expect the sprite to increase in visual size as it's width increases. For me, it doesn't. (http://www.adobe.com/livedocs/flash/9.0/ActionScriptLangRefV3/flash/display/DisplayObject.html#width)
width property
width:Number [read-write]
Indicates the width of the display object, in pixels. The width is calculated based on the bounds of the content of the display object. When you set the width property, the scaleX property is adjusted accordingly, as shown in the following code:
My code below doesn't affect the visual display at all - but it does set the width/height, at least according to the trace output. It does not affect the scaleX/scaleY.
What the heck am I missing here??
My setup code:
testSprite = new SpriteVisualElement();
var childSprite:SpriteVisualElement = new SpriteVisualElement();
childSprite.graphics.beginFill(0xFFFF00, 1);
childSprite.graphics.drawRect(0, 0, 200, 100);
childSprite.graphics.endFill();
childSprite.name = "child";
testSprite.addChild(childSprite);
container.addElement(testSprite);
testSprite.addEventListener(MouseEvent.CLICK, grow);
}
public function grow(event:MouseEvent):void
{
event.target.width += 5;
event.target.height += 5;
trace("grow", event.target.width);
}
If I understand the code correctly; you are changing the width / height of the sprite. But you are doing nothing to change the width/ height of the sprite's children.
In the context of a Flex Application, you can use percentageWidth and percentageHeight on the child to resize the child when the parent is resized. You could also add a listener to the the resize event and adjust sizing that way; preferably tying in to the Flex Component LifeCycle methods somehow.
I believe these approaches are all Flex specific, and dependent upon the Flex Framework. Generic Sprites, as best I understand, do not automatically size themselves to percentages of their parent container; and changing the parent will not automatically resize the parent's children.
I bet something like this would work:
public function grow(event:MouseEvent):void
{
event.target.width += 5;
event.target.height += 5;
childSprite.width += 5;
childSprite.height += 5;
trace("grow", event.target.width);
}
First, if you have a problem with a flex component, you can look over its source code.
In my environment, (as I installed flex SDK to C:\flex\flex_sdk_4.1), the source code for SpriteVisualElement is located at
C:\flex\flex_sdk_4.1\frameworks\projects\spark\src\spark\core\SpriteVisualElement.as
In the source code, you'll find that width property is overridden :
/**
* #private
*/
override public function set width(value:Number):void
{
// Apply to the current actual size
_width = value;
setActualSize(_width, _height);
// Modify the explicit width
if (_explicitWidth == value)
return;
_explicitWidth = value;
invalidateParentSizeAndDisplayList();
}
So, you cannot expect the auto-scaling of the component.
Making custom components will be one solution.
Here is a sample implementation of custom component.
Custom Component Example - wonderfl build flash online
I am trying to attach some of my actionscript class, inherited from Sprite, to my Flex application by attaching it to a UIComponent, then add UIComponent to a panel. However, the size of my Sprite class appears to be larger than the panel. So, I try to resize it using DisplayObject.scale property, but I need to know the size of my container. Since I try to make my code reusable, I figure that I should let my Sprite class handle the resize by getting it via its parent property (let's say, I can resize it by set
this.scaleX = this.parent.Width/this.width or something like this)
However, my Sprite class's parent, which is the UIComponent, has width/height of 0.
So, my question is:
1) Is there any better way to resize DisplayObject class to fit its container when attached to Flex object?
2) If you know, why my UIComponent's size remain 0 and my DisplayObject still appears at its full size?
Here's my code, using Flash Builder 4:
private var loader:Loader = new Loader();
private function testLoader():void {
var urlRequest:URLRequest = new URLRequest("http://localhost/welcome.png");
loader.load(urlRequest);
loader.contentLoaderInfo.addEventListener(Event.COMPLETE,onLoaderLoadComplete);
}
private function onLoaderLoadComplete(e:Event):void {
loader.contentLoaderInfo.removeEventListener(Event.COMPLETE,onLoaderLoadComplete);
var ui : UIComponent = new UIComponent();
ui.addChild(loader);
panelTest.addElement(ui);
trace("ui.width = " + ui.width);
trace("ui.height = " + ui.height);
trace("loader.width = " + loader.width);
trace("loader.height = " + loader.height);
trace("panelTest.width = " + panelTest.width);
trace("panelTest.height = " + panelTest.height);
}
And this is the result when run:
ui.width = 0
ui.height = 0
loader.width = 571
loader.height = 411
panelTest.width = 480
panelTest.height = 320
I think it's the other way around: the parent should set the child element size while rendering. You can override the updateDisplayList(unscaledWidth:Number, unscaledHeight:Number) method to set the size of your loader child. See Advanced Visual Components in ActionScript.
I guess that the size of your ui is not really 0. The size is updated later after the layout and rendering process. So you have to wait for the layout to complete after adding a component to stage.
About the remaining 0, unfortunately is a known (grrr) problem: http://www.mail-archive.com/flexcoders#yahoogroups.com/msg39998.html
You can try to access it in a hacked way (using the mx_internal namespace): get width of dynamically created custom uicomponent
Adding the sprite directly to the panel may also be helpful. This can be done by adding the loader to the panel's rawChildren: http://www.actionscript.org/forums/showthread.php3?p=728034
Enjoy.
Here is the problem. I've created custom RectangularBorder and set it as border skin for TitleWindow. After this manipulation inner content of window is starting at 0,0 point of it. How could I set offset of it?
Just setting top padding does not work because scroll bar still begins from the top of the window after this manipulation.
There are lots of problems with trying to skin panels in Flex 3, and TitleWindow inherits from Panel.
This is the best explanation I've seen. (I'm not the same Glenn referenced in the italics :)).
For programmatic skin it went out pretty simple. One should override function get borderMetrics to do so:
public override function get borderMetrics():EdgeMetrics
{
var borderThickness:Number = getStyle("borderThickness");
var cornerRadius:Number = getStyle("cornerRadius");
var headerHeight:Number = getStyle("headerHeight");
return new EdgeMetrics(
borderThickness,
borderThickness + headerHeight,
borderThickness,
borderThickness);
}
try to use padding-top , padding-left etc as a style for your TitleWindow
I have a function I wrote that gets the height of the application without scrolling. Meaning the height it would need to be to not have to scroll.
This is the function:
private function getContentHeight():Number
{
var height:Number = 0;
for(var i:uint = 0; i<this.numChildren; i++)
{
var d:DisplayObject = this.getChildAt(i) as DisplayObject;
//trace(d.name+":"+d.height);
height += d.height;
}
height += Number(this.getStyle('verticalGap'))*this.numChildren;
height += Number(this.getStyle('paddingTop'));
height += Number(this.getStyle('paddingBottom'));
return height;
}
This function works well but the problem is knowing when to call it. I planned on calling it after I add/remove any children from it. However thats still too soon because I don't get the correct height yet if I run it then. The fix I currently have is using a Timer to call the function about 300 milliseconds after a child is added/removed which seems to work well but I think this is a very risky fix. So I was wondering a better solution. I am thinking there has to be some sort of event I can listen for that will tell me when its ready for me to run this function, I just don't know what event that would be?
Thanks!
First of all, take a look at measuredWidth and measuredHeight properties of UIComponent (so all the controls and containers have these properties), flex already measures required width/height of the containers.
Secondly, the right place to look at this properties are creationComplete and updateComplete events. In your case, if you add some children programmaticaly, you should handle updateComplete event after you've added you children.