CheckBoxTree

Check box tree UI component

Since R2021a

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Description

A check box tree UI component displays a list of items in a hierarchy within an app, where each item has an associated check box. Use the CheckBoxTree object to modify the appearance and behavior of a check box tree after you create it.

Creation

Create a check box tree in an app using the uitree function, specifying the tree style as "checkbox".

Properties

Nodes

CheckedNodes — Checked nodes

[] (default) | TreeNode object | array of TreeNode objects

Checked nodes, specified as a TreeNode object or an array of TreeNode objects. Use this property to programmatically get or set the checked nodes in a check box tree.

If CheckedNodes contains a parent node, all the children of the parent node are automatically added to CheckedNodes. If CheckedNodes contains all the children of a parent node, the parent node is automatically added to CheckedNodes.

SelectedNodes — Selected node

[] (default) | TreeNode object

Selected node, specified as a TreeNode object. Use this property to get or set the selected node in a check box tree.

In the check box tree UI component, the selected node is indicated by a blue highlight.

Font and Color

FontName — Font name

system supported font name

Font name, specified as a system supported font name. The default font depends on the specific operating system and locale.

If the specified font is not available, then MATLAB^® uses the best match among the fonts available on the system where the app is running.

Example: 'Arial'

FontSize — Font size

positive number

Font size, specified as a positive number. The units of measurement are pixels. The default font size depends on the specific operating system and locale.

Example: 14

FontWeight — Font weight

'normal' (default) | 'bold'

Font weight, specified as one of these values:

• 'normal' — Default weight as defined by the particular font

• 'bold' — Thicker character outlines than 'normal'

Not all fonts have a bold font weight. For fonts that do not, specifying 'bold' results in the normal font weight.

FontAngle — Font angle

'normal' (default) | 'italic'

Font angle, specified as 'normal' or 'italic'. Not all fonts have an italic font angle. For fonts that do not, specifying 'italic' results in the normal font angle.

FontColor — Font color

[0 0 0] (default) | RGB triplet | hexadecimal color code | 'r' | 'g' | 'b' | ...

Font color, specified as an RGB triplet, a hexadecimal color code, or one of the options listed in the table.

RGB triplets and hexadecimal color codes are useful for specifying custom colors.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1]; for example, [0.4 0.6 0.7].

• A hexadecimal color code is a character vector or a string scalar that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Thus, the color codes "#FF8800", "#ff8800", "#F80", and "#f80" are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
"red"	"r"	[1 0 0]	"#FF0000"
"green"	"g"	[0 1 0]	"#00FF00"
"blue"	"b"	[0 0 1]	"#0000FF"
"cyan"	"c"	[0 1 1]	"#00FFFF"
"magenta"	"m"	[1 0 1]	"#FF00FF"
"yellow"	"y"	[1 1 0]	"#FFFF00"
"black"	"k"	[0 0 0]	"#000000"
"white"	"w"	[1 1 1]	"#FFFFFF"

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	"#0072BD"
[0.8500 0.3250 0.0980]	"#D95319"
[0.9290 0.6940 0.1250]	"#EDB120"
[0.4940 0.1840 0.5560]	"#7E2F8E"
[0.4660 0.6740 0.1880]	"#77AC30"
[0.3010 0.7450 0.9330]	"#4DBEEE"
[0.6350 0.0780 0.1840]	"#A2142F"

BackgroundColor — Background color

[1 1 1] (default) | RGB triplet | hexadecimal color code | 'r' | 'g' | 'b' | ...

Background color, specified as an RGB triplet, a hexadecimal color code, or one of the color options listed in the table.

RGB triplets and hexadecimal color codes are useful for specifying custom colors.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1]; for example, [0.4 0.6 0.7].

• A hexadecimal color code is a character vector or a string scalar that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Thus, the color codes "#FF8800", "#ff8800", "#F80", and "#f80" are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
"red"	"r"	[1 0 0]	"#FF0000"
"green"	"g"	[0 1 0]	"#00FF00"
"blue"	"b"	[0 0 1]	"#0000FF"
"cyan"	"c"	[0 1 1]	"#00FFFF"
"magenta"	"m"	[1 0 1]	"#FF00FF"
"yellow"	"y"	[1 1 0]	"#FFFF00"
"black"	"k"	[0 0 0]	"#000000"
"white"	"w"	[1 1 1]	"#FFFFFF"

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	"#0072BD"
[0.8500 0.3250 0.0980]	"#D95319"
[0.9290 0.6940 0.1250]	"#EDB120"
[0.4940 0.1840 0.5560]	"#7E2F8E"
[0.4660 0.6740 0.1880]	"#77AC30"
[0.3010 0.7450 0.9330]	"#4DBEEE"
[0.6350 0.0780 0.1840]	"#A2142F"

StyleConfigurations — Configurations of added styles

empty n-by-3 table array (default) | n-by-3 table array

This property is read-only.

Configuration of added styles created using the uistyle function, returned as an n-by-3 table array. Each row of the table array corresponds to a style that is currently applied to the check box tree. Styles that are added consecutively are given a style order number of n+1. The Target and TargetIndex columns specify the part of the tree that the style was added to. The Style column specifies the style class name.

Use this property if you want to remove a style from the tree using the removeStyle function.

Example: Remove a Style

First, add two styles to a tree.

fig = uifigure;
fig.Position = [100 100 250 350];
t = uitree(fig,'checkbox');
n1 = uitreenode(t,'Text','Fruits');
n11 = uitreenode(n1,'Text','Banana');
n12 = uitreenode(n1,'Text','Cherry');
n2 = uitreenode(t,'Text','Vegetables');
n21 = uitreenode(n2,'Text','Broccoli');
n22 = uitreenode(n2,'Text','Lettuce');
expand(t)

s1 = uistyle('FontColor',[0 0.4 0.7]);    % Blue
s2 = uistyle('FontColor',[0.1 0.5 0.1]);  % Green

addStyle(t,s1,'level',2);
addStyle(t,s2,'node',[n2 n21 n22]);

When you query t.StyleConfigurations, MATLAB returns a 2-by-3 table array. The level style was added to the tree first, so it is style order number 1. The TargetIndex value for the level style, {[ 2]}, indicates that the style was applied to the second level of nodes. Similarly, the second style was added to three nodes in the tree.

t.StyleConfigurations

ans =

  2×3 table

         Target     TargetIndex                Style          
         ______    ______________    _________________________

    1    level     {[         2]}    1×1 matlab.ui.style.Style
    2    node      {1×3 TreeNode}    1×1 matlab.ui.style.Style

Remove the second style that was added to the tree by specifying style order number 2. The tree component appearance updates to use only the first style.

removeStyle(t,2)

Interactivity

Visible — State of visibility

'on' (default) | on/off logical value

State of visibility, specified as 'on' or 'off', or as numeric or logical 1 (true) or 0 (false). A value of 'on' is equivalent to true, and 'off' is equivalent to false. Thus, you can use the value of this property as a logical value. The value is stored as an on/off logical value of type matlab.lang.OnOffSwitchState.

• 'on' — Display the object.

• 'off' — Hide the object without deleting it. You still can access the properties of an invisible UI component.

To make your app start faster, set the Visible property to 'off' for all UI components that do not need to appear at startup.

Editable — Node text editability

'off' (default) | on/off logical value

Node text editability, specified as 'off' or 'on', or as numeric or logical 1 (true) or 0 (false). A value of 'on' is equivalent to true, and 'off' is equivalent to false. Thus, you can use the value of this property as a logical value. The value is stored as an on/off logical value of type matlab.lang.OnOffSwitchState.

Set this property to 'on' to allow the user to edit the node text at run time. The Enable property must also be set to 'on' to make the text editable.

Enable — Operational state of tree

'on' (default) | on/off logical value

Operational state of tree, specified as 'on' or 'off', or as numeric or logical 1 (true) or 0 (false). A value of 'on' is equivalent to true, and 'off' is equivalent to false. Thus, you can use the value of this property as a logical value. The value is stored as an on/off logical value of type matlab.lang.OnOffSwitchState.

• If you set this property to 'on', the app user can interact with the tree and its nodes.

• If you set this property to 'off', the component appears dimmed, indicating that the app user cannot interact with it or its nodes, and that it will not trigger a callback.

Set this property to 'off' to make the tree and its nodes appear dim, indicating that the user cannot interact with the tree or its nodes.

Tooltip — Tooltip

'' (default) | character vector | cell array of character vectors | string array | 1-D categorical array

Tooltip, specified as a character vector, cell array of character vectors, string array, or 1-D categorical array. Use this property to display a message when the user hovers the pointer over the component at run time. The tooltip displays even when the component is disabled. To display multiple lines of text, specify a cell array of character vectors or a string array. Each element in the array becomes a separate line of text. If you specify this property as a categorical array, MATLAB uses the values in the array, not the full set of categories.

ContextMenu — Context menu

empty GraphicsPlaceholder array (default) | ContextMenu object

Context menu, specified as a ContextMenu object created using the uicontextmenu function. Use this property to display a context menu when you right-click on a component.

Position

Position — Location and size

[20 20 150 300] (default) | [left bottom width height]

Location and size, specified as a four-element vector of the form [left bottom width height]. This table describes each element in the vector. All measurements are in pixel units.

Element	Description
left	Distance from the inner left edge of the parent container to the left edge of the bounding box that encloses the tree
bottom	Distance from the inner bottom edge of the parent container to the bottom edge of the bounding box that encloses the tree
width	Distance between the right and left edges of the bounding box
height	Distance between the top and bottom edges of the bounding box

InnerPosition — Location and size

[20 20 150 300] (default) | [left bottom width height]

Location and size, specified as a four-element vector of the form, [left bottom width height]. The values in the vector are relative to the parent container. All measurements are in pixel units. This property value is identical to the Position property.

OuterPosition — Location and size

[20 20 150 300] (default) | [left bottom width height]

This property is read-only.

Location and size, returned as a four-element vector of the form, [left bottom width height]. The values in the vector are relative to the parent container. All measurements are in pixel units. This property value is identical to the Position property.

Layout — Layout options

empty LayoutOptions array (default) | GridLayoutOptions object

Layout options, specified as a GridLayoutOptions object. This property specifies options for components that are children of grid layout containers. If the component is not a child of a grid layout container (for example, it is a child of a figure or panel), then this property is empty and has no effect. However, if the component is a child of a grid layout container, you can place the component in the desired row and column of the grid by setting the Row and Column properties on the GridLayoutOptions object.

For example, this code places a check box tree in the third row and second column of its parent grid.

g = uigridlayout([4 3]);
cbt = uitree(g,'checkbox');
cbt.Layout.Row = 3;
cbt.Layout.Column = 2;

To make the tree span multiple rows or columns, specify the Row or Column property as a two-element vector. For example, this tree spans columns 2 through 3:

cbt.Layout.Column = [2 3];

Callbacks

CheckedNodesChangedFcn — Checked nodes changed callback

'' (default) | function handle | cell array | character vector

Checked nodes changed callback, specified as one of these values:

• A function handle.

• A cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

• A character vector containing a valid MATLAB expression (not recommended). MATLAB evaluates this expression in the base workspace.

Use this callback function to execute commands when the user checks or unchecks a node in the tree.

This callback function can access specific information about the user’s interaction with the tree, such as the previously checked nodes. MATLAB passes this information in a CheckedNodesChangedData object as the second argument to your callback function. In App Designer, the argument is called event. You can query the object properties using dot notation. For example, event.CheckedNodes returns the checked TreeNode object or objects. The CheckedNodesChangedData object is not available to callback functions specified as character vectors.

The following table describes properties of the CheckedNodesChangedData object.

Property	Description
CheckedNodes	Currently checked TreeNode objects
PreviousCheckedNodes	Previously checked TreeNode objects
IndeterminateCheckedNodes	Parent TreeNode objects that currently have both checked and unchecked children
PreviousIndeterminateCheckedNodes	Parent TreeNode objects that previously had both checked and unchecked children
LeafCheckedNodes	Currently checked TreeNode objects with no child nodes
PreviousLeafCheckedNodes	Previously checked TreeNode objects with no child nodes
ParentCheckedNodes	Currently checked TreeNode objects with child nodes
PreviousParentCheckedNodes	Previously checked TreeNode objects with child nodes
Source	Component that executes the callback
EventName	'CheckedNodesChanged'

Properties that return a list of nodes return them in a hierarchical order. For example, the CheckedNodes property first lists all checked nodes in the first level of the tree in the order in which they appear in the tree component. Then, it lists all checked nodes in the second level of the tree, again in the order in which they appear. This pattern continues until finally it lists the nodes in the last level of the tree. This matches the order that the findall function returns nodes in.

For more information about writing callbacks, see Callbacks in App Designer.

SelectionChangedFcn — Selection changed callback

'' (default) | function handle | cell array | character vector

Selection changed callback, specified as one of these values:

• A function handle.

• A cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

• A character vector containing a valid MATLAB expression (not recommended). MATLAB evaluates this expression in the base workspace.

Use this callback function to execute commands when the user selects a different node in the tree.

This callback function can access specific information about the user’s interaction with the tree, such as the selected node. MATLAB passes this information in a SelectedNodesChangedData object as the second argument to your callback function. In App Designer, the argument is called event. You can query the object properties using dot notation. For example, event.SelectedNodes returns the selected TreeNode object. The SelectedNodesChangedData object is not available to callback functions specified as character vectors.

The following table describes properties of the SelectedNodesChangedData object.

Property	Description
SelectedNodes	Most recently selected TreeNode object
PreviousSelectedNodes	Previously selected TreeNode object
Source	Component that executes the callback
EventName	'SelectionChanged'

For more information about writing callbacks, see Callbacks in App Designer.

NodeExpandedFcn — Node expanded callback

'' (default) | function handle | cell array | character vector

Node expanded callback, specified as one of these values:

• A function handle.

• A cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

• A character vector containing a valid MATLAB expression (not recommended). MATLAB evaluates this expression in the base workspace.

Use this callback function to execute commands when the user expands a node in the tree.

This callback function can access specific information about the user’s interaction with the node. MATLAB passes this information in a NodeExpandedData object as the second argument to your callback function. In App Designer, the argument is called event. You can query the object properties using dot notation. For example, event.Node returns the TreeNode object that the user collapsed. The NodeExpandedData object is not available to callback functions specified as character vectors.

The following table describes properties of the NodeExpandedData object.

Property	Description
Node	TreeNode object that the user expanded
Source	Component that executes the callback
EventName	'NodeExpanded'

For more information about writing callbacks, see Callbacks in App Designer.

NodeCollapsedFcn — Node collapsed callback

'' (default) | function handle | cell array | character vector

Node collapsed callback, specified as one of these values:

• A function handle.

• A cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

• A character vector containing a valid MATLAB expression (not recommended). MATLAB evaluates this expression in the base workspace.

Use this callback function to execute commands when the user collapses a node in the tree.

This callback function can access specific information about the user’s interaction with the node. MATLAB passes this information in a NodeCollapsedData object as the second argument to your callback function. In App Designer, the argument is called event. You can query the object properties using dot notation. For example, event.Node returns the TreeNode object that the user collapsed. The NodeCollapsedData object is not available to callback functions specified as character vectors.

The following table describes properties of the NodeCollapsedData object.

Property	Description
Node	TreeNode object that the user collapsed
Source	Component that executes the callback
EventName	'NodeCollapsed'

For more information about writing callbacks, see Callbacks in App Designer.

NodeTextChangedFcn — Node text changed callback

'' (default) | function handle | cell array | character vector

Node text changed callback, specified as one of these values:

• A function handle.

• A cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

• A character vector containing a valid MATLAB expression (not recommended). MATLAB evaluates this expression in the base workspace.

Use this callback function to execute commands when the user changes the text for a node in the tree.

This callback function can access specific information about the user’s interaction with the tree node. MATLAB passes this information in a NodeTextChangedData object as the second argument to your callback function. In App Designer, the argument is called event. You can query the object properties using dot notation. For example, event.PreviousText returns the previous node text. The NodeTextChangedData object is not available to callback functions specified as character vectors.

The following table describes the properties of the NodeTextChangedData object.

Property	Description
Node	TreeNode object that has changed text
Text	New node text
PreviousText	Previous node text
Source	Component that executes the callback
EventName	'NodeTextChanged'

For more information about writing callbacks, see Callbacks in App Designer.

ClickedFcn — Clicked function

'' (default) | function handle | cell array | character vector

Clicked function, specified as one of these values:

• A function handle.

• A cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

• A character vector containing a valid MATLAB expression (not recommended). MATLAB evaluates this expression in the base workspace.

This callback function executes when the user clicks anywhere in the tree.

This callback function can access specific information about the user’s interaction with the tree UI component. MATLAB passes this information in a ClickedData object as the second argument to your callback function. In App Designer, the argument is called event. You can query the object properties using dot notation. For example, event.InteractionInformation returns information about where the user clicked in the tree. The ClickedData object is not available to callback functions specified as character vectors.

This table lists the properties of the ClickedData object.

Property	Value
InteractionInformation	Information about where in the component the app user clicked. This information is stored as an object with these properties: Node Level ScreenLocation Location You can query the object properties using dot notation. For example, event.InteractionInformation.Node returns which node of the tree the user clicked.
Source	Component that executes the callback
EventName	'Clicked'

This table lists the properties of the InteractionInformation object associated with the tree UI component.

Property	Value
Node	The clicked node, returned as a TreeNode object. If the user clicked an area of the tree that is not associated with a node, then Node is an empty array.
Level	The level of the clicked node, returned as a scalar. Nodes parented directly to the Tree object are at level one, nodes parented to a node at level one are at level two, and so on. If the user clicked an area of the tree that is not associated with a node, then Level is an empty array.
ScreenLocation	The location where the user clicked relative to the bottom-left corner of their primary display, returned as a two-element vector of the form [x y]. The value of x represents the horizontal distance from the left edge of the display to the click location. The value of y represents the vertical distance from the bottom of edge of the display to the click location. Distances are measured in pixels.
Location	The location where the user clicked relative to the bottom-left corner of the tree parent container, returned as a two-element vector of the form [x y]. The value of x represents the horizontal distance from the left edge of parent container to the click location. The value of y represents the vertical distance from the bottom of edge of the parent container to the click location. Distances are measured in pixels.

For more information about writing callbacks, see Create Callbacks for Apps Created Programmatically.

Example: Open Dialog Box When Tree is Clicked

Create a tree with some tree nodes. Specify a ClickedFcn callback function named chooseIcon that executes when a user clicks the tree. In the chooseIcon function:

• Use the event.InteractionInformation object to access information about whether the user clicked a tree node.

• If the user did click a tree node (as opposed to a location in the tree that is not associated with a node), open a file selection dialog box for the user to choose an image for the tree node icon.

• Update the tree node icon to display the selected image.

• Bring keyboard focus back to the tree.

To try this example, save the code in a new script and run it. Click a node in the tree and select an icon image file.

fig = uifigure;
t = uitree(fig,"checkbox");
n1 = uitreenode(t);
n2 = uitreenode(t);
n11 = uitreenode(n1);
n21 = uitreenode(n2);
t.ClickedFcn = @chooseIcon;
expand(t)

function chooseIcon(src,event)
node = event.InteractionInformation.Node;
if ~isempty(node)
    [file,path] = uigetfile("*.png");
    if ~isequal(file,0)
        node.Icon = fullfile(path,file);
    end
    focus(src)
end
end

DoubleClickedFcn — Double-clicked function

'' (default) | function handle | cell array | character vector

Double-clicked function, specified as one of these values:

• A function handle.

• A cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

• A character vector containing a valid MATLAB expression (not recommended). MATLAB evaluates this expression in the base workspace.

This callback function executes when the user clicks anywhere in the tree.

This callback function can access specific information about the user’s interaction with the tree UI component. MATLAB passes this information in a DoubleClickedData object as the second argument to your callback function. In App Designer, the argument is called event. You can query the object properties using dot notation. For example, event.InteractionInformation returns information about where the user double-clicked in the tree. The DoubleClickedData object is not available to callback functions specified as character vectors.

This table lists the properties of the DoubleClickedData object.

Property	Value
InteractionInformation	Information about where in the component the app user double-clicked. This information is stored as an object with these properties: Node Level ScreenLocation Location You can query the object properties using dot notation. For example, event.InteractionInformation.Node returns which node of the tree the user double-clicked.
Source	Component that executes the callback
EventName	'DoubleClicked'

This table lists the properties of the InteractionInformation object associated with the tree UI component.

Property	Value
Node	The double-clicked node, returned as a TreeNode object. If the user double-clicked an area of the tree that is not associated with a node, then Node is an empty array.
Level	The level of the double-clicked node, returned as a scalar. Nodes parented directly to the Tree object are at level one, nodes parented to a node at level one are at level two, and so on. If the user double-clicked an area of the tree that is not associated with a node, then Level is an empty array.
ScreenLocation	The location where the user double-clicked relative to the bottom-left corner of their primary display, returned as a two-element vector of the form [x y]. The value of x represents the horizontal distance from the left edge of the display to the double-click location. The value of y represents the vertical distance from the bottom of edge of the display to the double-click location. Distances are measured in pixels.
Location	The location where the user double-clicked relative to the bottom-left corner of the tree parent container, returned as a two-element vector of the form [x y]. The value of x represents the horizontal distance from the left edge of parent container to the double-click location. The value of y represents the vertical distance from the bottom of edge of the parent container to the double-click location. Distances are measured in pixels.

For more information about writing callbacks, see Create Callbacks for Apps Created Programmatically.

Example: Open Dialog Box When Tree is Double-Clicked

Create a tree with some tree nodes. Specify a DoubleClickedFcn callback function named chooseIcon that executes when a user double-clicks the tree. In the chooseIcon function:

• Use the event.InteractionInformation object to access information about whether the user double-clicked a tree node.

• If the user did double-click a tree node (as opposed to a location in the tree that is not associated with a node), open a file selection dialog box for the user to choose an image for the tree node icon.

• Update the tree node icon to display the selected image.

• Bring keyboard focus back to the tree.

To try this example, save the code in a new script and run it. Double-click a node in the tree and select an icon image file.

fig = uifigure;
t = uitree(fig,"checkbox");
n1 = uitreenode(t);
n2 = uitreenode(t);
n11 = uitreenode(n1);
n21 = uitreenode(n2);
t.DoubleClickedFcn = @chooseIcon;
expand(t)

function chooseIcon(src,event)
node = event.InteractionInformation.Node;
if ~isempty(node)
    [file,path] = uigetfile("*.png");
    if ~isequal(file,0)
        node.Icon = fullfile(path,file);
    end
    focus(src)
end
end

CreateFcn — Creation function

'' (default) | function handle | cell array | character vector

Object creation function, specified as one of these values:

• Function handle.

• Cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

• Character vector containing a valid MATLAB expression (not recommended). MATLAB evaluates this expression in the base workspace.

For more information about specifying a callback as a function handle, cell array, or character vector, see Callbacks in App Designer.

This property specifies a callback function to execute when MATLAB creates the object. MATLAB initializes all property values before executing the CreateFcn callback. If you do not specify the CreateFcn property, then MATLAB executes a default creation function.

Setting the CreateFcn property on an existing component has no effect.

If you specify this property as a function handle or cell array, you can access the object that is being created using the first argument of the callback function. Otherwise, use the gcbo function to access the object.

DeleteFcn — Deletion function

'' (default) | function handle | cell array | character vector

Object deletion function, specified as one of these values:

• Function handle.

• Cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

• Character vector containing a valid MATLAB expression (not recommended). MATLAB evaluates this expression in the base workspace.

For more information about specifying a callback as a function handle, cell array, or character vector, see Callbacks in App Designer.

This property specifies a callback function to execute when MATLAB deletes the object. MATLAB executes the DeleteFcn callback before destroying the properties of the object. If you do not specify the DeleteFcn property, then MATLAB executes a default deletion function.

If you specify this property as a function handle or cell array, you can access the object that is being deleted using the first argument of the callback function. Otherwise, use the gcbo function to access the object.

Callback Execution Control

Interruptible — Callback interruption

'on' (default) | on/off logical value

Callback interruption, specified as 'on' or 'off', or as numeric or logical 1 (true) or 0 (false). A value of 'on' is equivalent to true, and 'off' is equivalent to false. Thus, you can use the value of this property as a logical value. The value is stored as an on/off logical value of type matlab.lang.OnOffSwitchState.

This property determines if a running callback can be interrupted. There are two callback states to consider:

• The running callback is the currently executing callback.

• The interrupting callback is a callback that tries to interrupt the running callback.

MATLAB determines callback interruption behavior whenever it executes a command that processes the callback queue. These commands include drawnow, figure, uifigure, getframe, waitfor, and pause.

If the running callback does not contain one of these commands, then no interruption occurs. MATLAB first finishes executing the running callback, and later executes the interrupting callback.

If the running callback does contain one of these commands, then the Interruptible property of the object that owns the running callback determines if the interruption occurs:

• If the value of Interruptible is 'off', then no interruption occurs. Instead, the BusyAction property of the object that owns the interrupting callback determines if the interrupting callback is discarded or added to the callback queue.

• If the value of Interruptible is 'on', then the interruption occurs. The next time MATLAB processes the callback queue, it stops the execution of the running callback and executes the interrupting callback. After the interrupting callback completes, MATLAB then resumes executing the running callback.

Note

Callback interruption and execution behave differently in these situations:

• If the interrupting callback is a DeleteFcn, CloseRequestFcn, or SizeChangedFcn callback, then the interruption occurs regardless of the Interruptible property value.

• If the running callback is currently executing the waitfor function, then the interruption occurs regardless of the Interruptible property value.

• If the interrupting callback is owned by a Timer object, then the callback executes according to schedule regardless of the Interruptible property value.

Note

When an interruption occurs, MATLAB does not save the state of properties or the display. For example, the object returned by the gca or gcf command might change when another callback executes.

BusyAction — Callback queuing

'queue' (default) | 'cancel'

Callback queuing, specified as 'queue' or 'cancel'. The BusyAction property determines how MATLAB handles the execution of interrupting callbacks. There are two callback states to consider:

• The running callback is the currently executing callback.

• The interrupting callback is a callback that tries to interrupt the running callback.

The BusyAction property determines callback queuing behavior only when both of these conditions are met:

• The running callback contains a command that processes the callback queue, such as drawnow, figure, uifigure, getframe, waitfor, or pause.

• The value of the Interruptible property of the object that owns the running callback is 'off'.

Under these conditions, the BusyAction property of the object that owns the interrupting callback determines how MATLAB handles the interrupting callback. These are possible values of the BusyAction property:

• 'queue' — Puts the interrupting callback in a queue to be processed after the running callback finishes execution.

• 'cancel' — Does not execute the interrupting callback.

BeingDeleted — Deletion status

on/off logical value

This property is read-only.

Deletion status, returned as an on/off logical value of type matlab.lang.OnOffSwitchState.

MATLAB sets the BeingDeleted property to 'on' when the DeleteFcn callback begins execution. The BeingDeleted property remains set to 'on' until the component object no longer exists.

Check the value of the BeingDeleted property to verify that the object is not about to be deleted before querying or modifying it.

Parent/Child

Parent — Parent container

Figure object (default) | Panel object | Tab object | ButtonGroup object | GridLayout object

Parent container, specified as a Figure object created using the uifigure function, or one of its child containers: Tab, Panel, ButtonGroup, or GridLayout. If no container is specified, MATLAB calls the uifigure function to create a new Figure object that serves as the parent container.

Children — Children

empty GraphicsPlaceholder array (default) | array of TreeNode objects

Children, returned as an array of TreeNode objects.

You cannot add or remove children using the Children property, but you can use the property to view the list of children. The order of the children reflects the order of the child nodes displayed on the screen. To add a child to this list, set the Parent property of the child component to be the Tree object.

To reorder the children, use the move function.

Objects with the HandleVisibility property set to 'off' are not listed in the Children property.

HandleVisibility — Visibility of object handle

'on' (default) | 'callback' | 'off'

Visibility of the object handle, specified as 'on', 'callback', or 'off'.

This property controls the visibility of the object in its parent's list of children. When an object is not visible in its parent's list of children, it is not returned by functions that obtain objects by searching the object hierarchy or querying properties. These functions include get, findobj, clf, and close. Objects are valid even if they are not visible. If you can access an object, you can set and get its properties, and pass it to any function that operates on objects.

HandleVisibility Value	Description
'on'	The object is always visible.
'callback'	The object is visible from within callbacks or functions invoked by callbacks, but not from within functions invoked from the command line. This option blocks access to the object at the command-line, but allows callback functions to access it.
'off'	The object is invisible at all times. This option is useful for preventing unintended changes to the UI by another function. Set the HandleVisibility to 'off' to temporarily hide the object during the execution of that function.

Identifiers

Type — Type of graphics object

'uicheckboxtree'

This property is read-only.

Type of graphics object, returned as 'uicheckboxtree'.

Tag — Object identifier

'' (default) | character vector | string scalar

Object identifier, specified as a character vector or string scalar. You can specify a unique Tag value to serve as an identifier for an object. When you need access to the object elsewhere in your code, you can use the findobj function to search for the object based on the Tag value.

UserData — User data

[] (default) | array

User data, specified as any MATLAB array. For example, you can specify a scalar, vector, matrix, cell array, character array, table, or structure. Use this property to store arbitrary data on an object.

If you are working in App Designer, create public or private properties in the app to share data instead of using the UserData property. For more information, see Share Data Within App Designer Apps.

Object Functions

addStyle	Add style to UI component
removeStyle	Remove style from UI component
scroll	Scroll to location within component
expand	Expand tree node
collapse	Collapse tree node
focus	Focus UI component

Examples

Create Callbacks for Check Box Tree Interactions

Create an app that displays a grocery list grouped by food category. The app user can check individual items or entire food categories, and MATLAB displays the total weight of the checked items.

Create a program file called mycheckboxtreeapp.m that contains the following commands to create a check box tree, a set of nested tree nodes, and two callback functions for the check box tree. The CheckedNodesChangedFcn property specifies the function to execute when the user checks or unchecks a node in the tree. The SelectedNodesChangedFcn property specifies the function to execute when the user selects a node in the tree.

function mycheckboxtreeapp
    fig = uifigure;
    cbt = uitree(fig,'checkbox','Position',[20 20 150 150]);
    
    % Assign callbacks in response to node check and selection
    cbt.CheckedNodesChangedFcn = @checkchange;
    cbt.SelectionChangedFcn = @selectchange;
    
    % First level nodes
    category1 = uitreenode(cbt,'Text','Vegetables','NodeData',[]);
    category2 = uitreenode(cbt,'Text','Fruits','NodeData',[]);

    % Second level nodes.
    % Node data is the weight of the food item (in grams)
    p1 = uitreenode(category1,'Text','Cucumber','NodeData',400);
    p2 = uitreenode(category1,'Text','Carrot','NodeData',65);
    p3 = uitreenode(category2,'Text','Apple','NodeData',183);
    p4 = uitreenode(category2,'Text','Banana','NodeData',120);

    % Expand the tree
    expand(cbt);
    
    % Create the function for the CheckedNodesChangedFcn callback
    % When this function is executed, it displays the total weight
    % of all checked items
    function checkchange(src,event)
        nodes = event.LeafCheckedNodes;
        if ~isempty(nodes)
            data = [nodes.NodeData];
            display(sum(data));
        end
    end

    % Create the function for the SelectedNodesChangedFcn callback
    % When this function is executed, it displays the name
    % of the selected item
    function selectchange(src,event)
        node = event.SelectedNodes;
        display(node.Text);
    end
end

When the user runs mycheckboxtreeapp and checks or unchecks a node in the tree, MATLAB displays the sum of the weights (stored in NodeData) for all the second-level checked nodes. When the user selects a node in the tree, MATLAB displays the text of that node.

Version History

Introduced in R2021a