I am developing an isometric game.
I have a parent UIComponent (WorldMap). The player can choose MapElement s (game items) and drop them in the playable area WorldMap. This MapElement also is a UIComponent which contains child controls such as Sprite, Image, Label and custom Flex components to hold various information.
Now, I have written a logic to determine which one should appear in back and which one should appear in front in the Isometric area which I am calling idx (index) and I am seeting this value to the depth property of the MapElement.
I have added three components in the order shown in below pic and I have set the depth property each of them as 11077,11168 and 10630. If the depth property worked properly the 3rd item should have gone behind the 1st item but it seems like they are appearing in the order of they have added (default behavior)
If I am not wrong the depth value can be anything
Can some one help me?
I am aware of another solution using swapChildren, swapChildrenAt and and also addChildAt methods (which I don't want to use for my project specific reason) but I need to find out whats wrong with the depth
The problem, as I think, in your WorldMap component which, as you said, is UIComponent. Diving deeper to depth property shows that depth setter launches invalidateLayering method, which is empty in UIComponent and overrides with logic only in Group which is main container for every Flex 4 component. And here's example:
http://www.tink.ws/blog/flex-4-uicomponent-depth/
So, it looks like, you need to use at least Group or SkinnableContainer as your WorldMap in order to achieve depth property to work correctly.
Use UIComponent.addChildAt(child:DisplayObject, index:int). addChildAt adds a child DisplayObject instance to this DisplayObjectContainer instance. The child is added at the index position specified. An index of 0 represents the back (bottom) of the display list for this DisplayObjectContainer object.
Related
I have a QGraphicsScene with many QGraphicsItem like circle, rectangle, polylines, arc etc.
Every QGraphicsItem has a name. And I have a Search feature which highlights searched items using that name. When scene contains fewer items, highlighted items are seen properly. But when scene contains many items ( 100 + ) then identifying the highlighted item becomes difficult. For that I need to scroll up - down or left - right to check where is that highlighted item is.
So I want my highlighted item to be easily recognizable.
For that I was suggested, some approach like
Take searched item in front
Or
Add some marker
But I do not know, how to implement it , which Qt class should I use etc.
QGraphicsScene displays items depending on their stacking, i.e., when you call .items(), the first item in the QList is the topmost item on the scene.
The ordering of the items is depending on their respective Z-values which you can set for the QGraphicsItem by calling .setZValue()
You can read more about this on the following link: https://doc.qt.io/qt-5/qgraphicsitem.html#sorting
As for your question on how to put them in front. If you implemented your own children classes of QGraphicsItem, you can add a method or a slot to toggle them "on-top". E.g., all of the items usually have a Z-order of 0, so your method could just set it to 1 when the item is highlighted and revert it to 0 when it's not.
How can I change the z axis of components and put one in front of the other? The new layout property in Flex 4 has changed significantly & now not sure how to do it.
It works the same way that it did in Flex 3. A components Z order is defined by the order in which they are placed as child of their parent. The second child will be in front of the first child, and the third child will be in front of the first and second child and so on.
You can still use swapChildren and swapChildrenAt to change the Z-order of children.
The layout property's value will be an instance of a Layout class; which--in a simple form your measure() and updateDisplayList() methods. IT does not, specifically, relate to moving one component in front of, or behind, another.
On a Flex 4 group, you can use swapElement and swapElementsAt, although I would bet if you were to examine the code you'd find that these are just layers of abstraction over swapChildren and swapChildrenAt.
checkout the new depth property introduced in Flex 4 e.g. see http://www.tink.ws/blog/flex-4-uicomponent-depth/
Maybe this help:
container's depth
you can use depth property of flex containers to define which element can overlap other elements.
I want to create an MXML container component that has some of its own chrome -- a standard query display, et al -- and that supports the addition of child components to it. Something a lot like the existing mx:Panel class, which includes a title label, but acts like a plain mx:Box with regards to adding children.
What's the easiest way to do this?
Edit:
To be clear, I want to be able to extend the container using MXML, so the "Multiple visual children" problem is relevant.
Extend a container and add a title label. Probably the <mx:Canvas/> will work here. Make the title a public var and include a var for the styleName of the label.
Then override the addChild() method so that any child that is added is added instead to the that is your container.
Leave enough space for your title when you position your Box element (i.e., give its y property enough space. If there is no title you may want to reclaim that space.
That's the basics. Customize to your heart's content.
EDITED TO ADD: I do this creating an ActionScript class first, extending the container I am targeting, and I add the "furniture" — items the class will always use, like title in your case — by overriding createChildren and calling super.addChild(item) for those items. Calling addChild from then on, even in MXML markup, adds items to the inner container.
We do this with states.
We put the chrome for the base container in a state (in mx:AddChild elements) and then use the initialize event to switch to that state when the control is created. All the chrome is then added to the container.
That gets round the multiple sets of visual children problem.
The downsides to this approach are:
You don't see the chrome when editing descendents of the base.
You can't directly access the parent chrome controls from descendent components as they are not there at compile time (instead, you need to define properties, methods or events on the base that the descendents can access)
However, it works well for us.
I have a quick question about rendering the advanceddatagrid cells.
I need to programatically color the cell of the datagrid based on the conditions. Lets say, the stock quotes. If there is an increase from the previous day, I need to have the cell colored in GREEN and in RED, when there is a decrease.
Now, the important part here is, I need to do these things dynamically, which means, when the user enables the comparison/conditions, then the cells are colored. And when the user disables the comparison, then it again goes back to its default behavior.
I know I have to use renderers. But not sure, how to use it for the cells and that too dynamically. Can anyone please explain how to go for it?
Thanks
Item renderers are components used to define the appearance of a component's "items" or subcomponents. In the case of the ADG, the "items" are the individual cells. You can create a completely custom class to function as the renderer (given it implements certain required interfaces) or, in most cases, you extend an existing component. Since the default renderer for ADG cells doesn't support background colors, you have to create or extend a component that does and use that as the renderer. That is the basic premise that these tutorials, linked to in the following question, work from:
Setting background color for datagrid row in Adobe Flex
After creating an itemRenderer that supports a background color, you have two options as to where you can define your "conditions"; inside of the itemRenderer or using the ADG's styleFunction (additionally requiring that your itemRenderer defines a "background" style).
In your case, you could include both today's and yesterday's stock price values in the data sent to each cell and compare the two to determine the color used to draw the background. Again, more on that in the tutorial links provided above. In either the itemRenderer or the styleFunction, you would compare properties on the itemRenderer's/styleFunction's data object (corresponding to the row you're looking at), e.g.:
if(data.today > data.yesterday)
{
// set color or return style
}
else ...
To "toggle" custom cell colors, switch between your custom renderer and the default (colorless) renderer. In other words, set the itemRenderer property to your custom itemRenderer class when you need display the colors and set it to "null" when you want the "default behavior".
What is the best way to change/set a registration point on a Flex 3 display object? I know this isn't really built in to easily change, but does anyone have any suggestions on how I could extend UIComponent to achieve this?
For some reason, the Flash Player API doesn't expose the registration point of DisplayObjects (and the Flash IDE makes them a pain to modify once an object is created). The best solution, as David pointed out, is to add your component as a child of another component (UIComponent would be fine). So, for example, if I had a Button and I wanted its registration point at its center, I'd add it as a child of a UIComponent (not Canvas) and offset the child by setting its position to (-button.width/2, -button.height/2).
Put your DisplayObject inside a sprite and set the DisplayObject's x & y positions to the negitive of your target registration point. Apply all transforms to the Sprite container.
Put it inside a Canvas container, with its clipContent attribute set to false. Within the canvas, you can put your object wherever you like.