Comments on: Detecting window focus events

By: Kesh

Kesh — Mon, 09 Aug 2010 17:22:11 +0000

@Donn, thanks for the tip! That’ll do for me.

By: Donn

Donn — Sat, 07 Aug 2010 19:13:01 +0000

@Kesh – Even though the callback properties are not available the corresponding events are still generated. You can create listeners to them with:

   l = handle.listener(handle(jAxis), 'FocusGained', @callback)

It is not as convienent as the callback properties, but it works.

By: Kesh

Kesh — Thu, 05 Aug 2010 18:59:20 +0000

That’s a bummer. I wonder if there is any way for us to “attach” CallbackProperties after FIG is loaded… If you learn a way around for it, please let me know!

By: Yair Altman

Yair Altman — Thu, 05 Aug 2010 18:01:44 +0000

@Kesh - this is an undocumented bug in the way Matlab loads FIG files - it loads Java objects without the 'CallbackProperties' argument (so some equivalent action), causing the object's callbacks not to be visible in Matlab. Apparently, only GUI figures and components created in run-time have accessible callbacks. This sounds odd, and I would love to learn how to bypass this limitation, but at the moment I don't know if this is possible.

By: Kesh

Kesh — Mon, 02 Aug 2010 14:43:46 +0000

Oops, I mistakenly placed “” text in MATLAB code block. For the first get(jAxis) returned values, there are many other Callback Fields between “MouseWheelMovedCallbackData = []” and ” KeyTypedCallback = “

By: Kesh

Kesh — Mon, 02 Aug 2010 14:41:22 +0000

Hey Yair,

It’s me again. I got a funny behavior when trying to access figure focus callbacks of saved figure. Here’s an example:

Open a plain figure with nothing in it and get the AxisComponent properties:

figure
jFig = get(handle(gcf), 'JavaFrame');
jAxis = jFig.getAxisComponent;
get(jAxis)

returns what we expect:

	UIJGraphics = []
	AccessibleContext = [ (1 by 1) java.awt.Canvas$AccessibleAWTCanvas array]
	Background = [0.92549 0.913725 0.847059]
	BufferStrategy = []
	Component = [ (1 by 1) com.mathworks.hg.peer.FigureAxisComponentProxy$_AxisCanvas array]
	ComponentLightweight = off
	Enabled = on
	Focusable = on
	Font = [ (1 by 1) javax.swing.plaf.FontUIResource array]
	Foreground = [0 0 0]
	Graphics = [ (1 by 1) com.mathworks.hg.peer.AxisCanvas$HGDebugGraphics array]
	Name = fAxisComponentProxy
	NativeWindowHandle = [0]
	NativeWindowHandleValid = off
	MouseWheelMovedCallback = 
	MouseWheelMovedCallbackData = []
 
	KeyTypedCallback = 
	KeyTypedCallbackData = []
 
	BeingDeleted = off
	ButtonDownFcn = 
	Children = []
	Clipping = on
	CreateFcn = 
	DeleteFcn = 
	BusyAction = queue
	HandleVisibility = on
	HitTest = on
	Interruptible = on
	Parent = []
	Selected = off
	SelectionHighlight = on
	Tag = 
	Type = com.mathworks.hg.peer.FigureAxisComponentProxy$_AxisCanvas
	UIContextMenu = []
	UserData = []
	Visible = on

But, when this figure is saved and loaded again:

hgsave test
hgload test
 
jFig1 = get(handle(gcf), 'JavaFrame');
jAxis1 = jFig1.getAxisComponent;
get(jAxis1)

Now, AxisComponent properties are crippled:

                UIJGraphics: []
          AccessibleContext: [1x1 java.awt.Canvas$AccessibleAWTCanvas]
                 Background: [1x1 javax.swing.plaf.ColorUIResource]
             BufferStrategy: []
                  Component: [1x1 com.mathworks.hg.peer.FigureAxisComponentProxy$_AxisCanvas]
       ComponentLightweight: 0
                    Enabled: 1
                  Focusable: 1
                       Font: [1x1 javax.swing.plaf.FontUIResource]
                 Foreground: [1x1 javax.swing.plaf.ColorUIResource]
                   Graphics: [1x1 com.mathworks.hg.peer.AxisCanvas$HGDebugGraphics]
                       Name: 'fAxisComponentProxy'
         NativeWindowHandle: 0
    NativeWindowHandleValid: 0

The callback fields are no longer accessible among many others. Do you know why this happens and/or how to work around this problem to get to the focus callbacks?

TIA

By: Yair Altman

Yair Altman — Fri, 30 Jul 2010 09:32:13 +0000

@David – have a look here: http://UndocumentedMatlab.com/blog/uicontrol-callbacks/
I don’t have an immediate solution to the performance issue. JTextArea is usually performant, since it doesn’t have different fonts/styles like JEditorPane or JTextPane. Perhaps the bottleneck is in one of your callbacks or listeners?

By: David

David — Fri, 30 Jul 2010 07:47:02 +0000

Hi,

I am working with a java component in matlab. I have wrapped a JTextArea and added a scroll and some features to it. I have two problems that I would like to solve:

1) I need a callback to use when something changes in the text area. I would like to use this to implement a UNDO, crl+z, feature. Do you know a suitable callback for this?

2) When I work with the text area it is very slow to render and repaint. If i delete some text, paste large blocks etc it might not render. I have tried calling repaint without success. Do you have a solution for this?

-David

By: Donn Shull

Donn Shull — Sat, 19 Sep 2009 05:36:57 +0000

I think I found this in some of your code on the MathWorks file exchange, anyway if you don’t like having to turn warnings off you can use the undocumented use of handle as a function to get the underlying figure object and access the JavaFrame property from there without generating a warning.

hFig = figure;
obj = handle(hFig);
jFig = obj.JavaFrame;

Thanks for the great work Yair.