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'}. For example: findjobj(...,'property', {'Text','click me'}) returns all elements with the specified text label
• '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 condition. For example: findjobj(...,'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. Notes: (1) optional PropValue of element index or handle to java container; (2) normally this option would be placed last, after all filtering is complete. The elements are returned in the 4th (listing) output argument - see below.
• 'list' - same as 'print'
• 'nomenu' - skip menu processing, for "lean" list of handles & much faster processing
• 'debug' - list (in the Command Window) the positions and handles of all components encountered in the container during findjob's search

Outputs:

• handles - list of reference 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' properties were not requested

Usage examples:

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