Flex: Modify an embedded icon and use it in a button? - apache-flex

Just that, if you embed an icon:
[Embed(source='icons/checkmark.png')]
private static var CheckMark:Class;
You end up with a dynamic class. You can pretty easily assign the icon to a button at runtime by calling the setStyle method:
var btn:Button = new Button();
btn.setStyle("icon", CheckMark);
But what if you wanted to alter the icon at runtime, like changing it's alpha value or even redrawing pixels, before assigning it to the button?
So far I can't find a satisfactory answer...

This is the only answer I could find that seemed close: Dynamic Icons (example with View Source)
His solution involves a custom "DynamicIcon" class which is used in the button's icon setting, and a custom Button class which adds one method to the Button class to draw dynamic icons.
The end result is that you are able to send BitmapData to the DynamicIcon class, which will show up in the button. So, embed your image, instantiate your asset class, get the bitmapasset and modify it however you need to and send the bitmapData to the icon.
It's an interesting problem and it seems like there should be an easier solution, but this works without a lot of hassle.

The way I'd solve this is to implement a programmatic skin class that draws the icon itself manually. There's probably more work you'll have to do to ensure the button calculates the correct size as if it has an icon even though it doesn't. You may have to poke through the Button source code to look at how the reference to the icon is stored.
I love just creating programmatic skins that do exactly what I want and then using interesting CSS declarations to modify states - for instance:
button.setStyle("customIconAlpha", .4);
and then of course the skin or the custom button class would have:
var alpha:Number = getStyle("customIconAlpha") as Number;
(not sure if you have to typecast that one)

The big problem I found with programmatic skins is that the button refuses to measure the width/height. I easily got around this by overriding the get methods for each:
override public function get width():Number { return WIDTH; }
override public function get height():Number { return HEIGHT; }
In my case I needed to modify buttons in a TabNavigator, hence no easy way to subclass the button. Thankfully, the parent of each skin is the button, so using static methods within your skin, you can identify the instance of the Button to which the icon skins belong.
If you're using the cover-all "icon" style, a new skin object will be created for each state. So you'll need to keep this in mind when changing the state of the icons.

Related

What kind of button does DatePicker and ComboBox use?

I have been trying to find the button that DatePicker and ComboBox uses. I have searched through ComboBoxBase, and all other similar classes, and have been unable to find it. Is there a public version of this?
There is no ComboBoxButton class or public method that creates such a thing. You can try to reproduce what's done in the specific controls by referring to the source code.
The look of the JavaFX controls are defined in their skin classes; so ComboBoxBaseSkin for ComboBox, with some supporting classes for the popup and list view that's displayed inside the popup. For the most part, the skin class defines the layout and behavior (i.e. response to user input), and the actual look (shape of the arrow, colors, etc) is defined by the CSS file.
These buttons are defined in a pretty non-trivial way; for ComboBox the arrow itself is defined as a Region, which is placed inside the arrowButton, which is a StackPane. Then the CSS file defines the shape of the arrow and different colors and borders depending on whether it's pressed, selected, etc.
The source for JavaFX is available via OpenJFX:
Home
ComboBoxBaseSkin
modena.css
In the CSS file, I would search for combo-box (there's a couple of dozen occurrences), and pay particular attention to the .arrow-button and .arrow classes.

How can I customize the appearance of the actions in my QToolBar?

I have just changed some toolbars from Q3ToolBars (with QToolButtons explicitly added to them) into Q4 toolbars (with actions added to them straight away instead.)
The old tool buttons had a nice outline around them, but this is not displayed in the new version; the QActions in the Q4 toolbar just look like a line of icons. Is there a way to change the 'button' style in the new version (assuming these actions can be considered as such) and give them the outline? I've looked through the QToolBar reference, but the toolButtonStyle() function only appears to work with whether you want to display icon, text, etc.
...Or will I have to just make actual tool buttons and/or QPushButtons and use addWidget()?
The widget associated with a given action is accessible through QToolBar::widgetForAction (since Qt 4.2). So, you can pass your actions to this method, get the QWidgets returned by it, convert them to QToolBar, and handle them like you normally would (code not tested):
// ...
auto toolButton =
static_cast<QToolButton *>(
m_ui.toolbar->widgetForAction(m_ui.my_Action));
// Will make the toolButton always appear raised:
toolButton->setAutoRaise(false);
// ...
As far as I've been testing, some methods might not work (i.e., QWidget::hide), so do your own testing.
Yes, of course you can edit look of QToolButtons in two different ways:
You can set it style sheet using void QWidget::setStyleSheet(const QString &)
You can reimplement QToolButtons class with new paintEvent function where you will be able to exactly set how your button should looks like.

How to completely initialise a component but not add it to the display? Flex

I need to completely initialize a custom component in my Flex app (i.e. I should be able to access it from action script and get its properties and its children etc), But I do not want to add it to the display or make it visible.
I have tried to add it to my visible component, but keep it visible, but often many of its properties are set only when it is drawn, so i don't get what i need.
Is there a way to add a custom component to some sort of 'Virtual' display, that is not visible to the user?
You could add the component to an invisible Sprite - that way the component itself could both be on the stage and have its own visible property set to true.
Did you try using initialize()? After a view is added to the display list, the initialization stage begins. Calling initialize() before addChild() should let you initialize the view without needing to first add it to the stage.
For more info visit:
http://flexscript.wordpress.com/2008/10/24/flex-component-lifecycle-and-flex-component-framework/
http://blog.deadinkvinyl.com/2008/10/05/flex-3-addchild-and-initialize/
Not sure if possible without adding it to the display list, although I'd wish it were to some extent.
I once had to make custom drag proxy, which didn't work with the real component, because of some weird skinning issues. So instead I had PopupMananger add a box as a popup, added my component to the box, called validateNow on the component, drew it in a bitmap data, removed the popup, and used the bitmap data as the proxy.
So what you were trying was missing a call to validateNow most likely.

Make a Spark TitleWindow modal without using much AS3?

I want to be able to show a Spark TitleWindow container as a modal without having to construct it by code via AS3. I tried creating the TitleWindow before-hand manually by dragging and resizing it around and adding objects, etc then hiding it. Then on a button, I set the called function to the ones below:
public function doPopup():void {
testWindow.visible = true;
PopUpManager.addPopUp(testWindow, this, true);
}
Unfortunately, this only shows testWindow but not as a modal. I want it to be like this so that I can freely resize and design the layout of my TitleWindow and only have to call some function to show it as a modal one.
I'm pretty sure the reason you are seeing this behavior is because your TitleWindow (that you've declared within the mxml of the parent container) is already added to the stage even though it is set as not visible. A workaround you could try is to call this.removeElement(testWindow) in a creation complete handler for the parent container. That will get it off the stage so the PopUpManager can add it later properly.
Having said that, I would recommend putting your TitleWindow into a separate mxml file and instantiate it using the PopUpManager. It's cleaner that way and you can still use the design mode to lay it out as you see fit.
Hope that helps.
Try the Cairngorm 3 Popup library :
http://opensource.adobe.com/wiki/display/cairngorm/HowToUseCairngormPopup

how can I write a generic property modification function in Flex/Actionscript3?

I'm new to Flex, although not new to programming. I want to write a generic event handler that will be called by all my textinput boxes when they receive focus. When they have focus, I want to change the colour of the textinput box. When they lose focus, I want to restore the "inactive" color profile. I could write an ActionScript event handler for each textinput box, but we all know that's lame. :o) What I need, then, is a way to access the object which is calling the event handler.
In Delphi, I'd have written a function which passes in the Sender object, allowing me to access the calling object's properties. I'm guessing ActionScript/Flex has a completely different architecture, which is why I'm having difficulty doing this.
Thanks in anticipation!
You should subclass TextInput and handle the focus events in there. I think this would be the simplest way to achieve what you are looking for without having any complex code.
I hope I'm understanding what you're asking for... are you talking about event delegation?
This worked for me:
// 'focusOut' for blur
stage.addEventListener('focusIn', function(e:Event):void {
// The focused control is e.target
});
If you want to change the look of the focused input box, you can do this by setting the focusSkin property. If you want this to happen globally, you can put a style declaration in your CSS file.
In this CSS example I'm replacing the default focusSkin (mx.skins.halo.HaloFocusRect) with an embedded PNG file.
TextInput {
focusSkin: Embed(source="focus.png");
}
TextInput has a few properties for altering the look of the focus, like changing the opacity of the focus skin (focusAlpha property). Check the TextInput documentation for more info.

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