findjobj - find java handles of Matlab graphic objects

Find java objects contained within a specified java container or Matlab GUI handle

Find all java objects contained within a java container or Matlab GUI handle

If no output parameter is specified, then an interactive GUI window will be displayed with a tree-view of all container components, their properties and callbacks.

Syntax:
[handles,levels,parentIds,listing] = findjobj(container,'PropName',PropValue(s),...)

Inputs:
- container - optional GUI handle. If unsupplied then current figure will be used
- 'PropName',PropValue - optional list of case insensitive property pairs. PropName may also be named -PropName.

Supported properties:
- 'position' - filter results based on those elements that contain the specified X,Y position or a java element
Note: specify a Matlab position (X,Y = pixels from bottom left corner), not a java one
- 'size' - filter results based on those elements that have the specified W,H (in pixels)
- 'class' - filter results based on those elements that contain the substring (or java class) PropValue
Note: filtering is case insensitive and relies on regexp, so you can pass wildcards etc.
- 'property' - filter results based on elements that possess the specified case-insensitive property string or have property values in cell array format: {'propName', 'propValue'}. Example: findjobj(...,'property', {'Text','click me'})
- 'depth' - filter results based on specified depth. 0=top-level, Inf=all levels (default=Inf)
- 'flat' - same as: 'depth',0
- 'not' - negates the following filter: 'not','class','c' returns all elements EXCEPT those with class 'c'
- 'persist' - persist figure components information, allowing much faster results for subsequent invocations
- 'print' - display all java elements in a hierarchical list
Note1: optional PropValue of element index or handle to java container
Note2: normally this option would be placed last, after all filtering is complete.
- 'list' - same as 'print'

Outputs:
- handles - list of handles to java elements
- levels - list of corresponding hierarchy level of the java elements (top=0)
- parentIds - list of indexes (in unfiltered handles) of the parent container of the corresponding java element
- listing - results of 'print'/'list' options (empty if 'print'/'list' were unspecified)

Sample usage:
>> hButton = uicontrol('string','click me');
>> jButton = findjobj(hButton,'nomenu'); % or: jButton = findjobj('property',{'Text','click me'});
>> jButton.setFlyOverAppearance(1);
>> jButton.setCursor(java.awt.Cursor.getPredefinedCursor(java.awt.Cursor.HAND_CURSOR));
>> set(jButton,'FocusGainedCallback',@myMatlabFunction); % some 30 callback points available...
>> jButton.get; % list all changeable properties...
>> hEditbox = uicontrol('style',edit');
>> jEditbox = findjobj(hEditbox,'nomenu');
>> jEditbox.setCaretColor(java.awt.Color.red);
>> jEditbox.KeyTypedCallback = @myCallbackFunc; % many more callbacks where this came from...
>> jEdit.requestFocus;
(Many more examples in the utility's help section)

Known issues/limitations:
- Cannot currently process multiple container objects - just one at a time
- Initial processing is a bit slow when the figure is laden with many UI components (so better use 'persist')
- Passing a container Matlab handle is currently found by position+size: should find a better way to do this
- Labels have a write-only text property in java, so can't be found using 'property',{'Text','string'} notation

Technical description:
* https://UndocumentedMatlab.com/articles/findjobj-find-underlying-java-object
* https://UndocumentedMatlab.com/articles/findjobj-gui-display-container-hierarchy

Warning:
This code heavily relies on undocumented and unsupported Matlab functionality. It works on Matlab 7+, but use at your own risk!

Bugs and suggestions:
Please send to Yair Altman (altmany at gmail dot com)

See also:
java, handle, findobj, findall