uitextarea

Create text area component

Syntax

txa = uitextarea

txa = uitextarea(parent)

txa = uitextarea(___,Name,Value)

Description

txa = uitextarea creates a text area in a new figure window and returns the TextArea object. MATLAB^® calls the uifigure function to create the figure.

txa = uitextarea(parent) creates the text area in the specified parent container. The parent can be a Figure created using the uifigure function, or one of its child containers.

txa = uitextarea(___,Name,Value) specifies TextArea properties using one or more Name,Value pair arguments. Use this option with any of the input argument combinations in the previous syntaxes.

Examples

Create Text Area in Figure Window

fig = uifigure;
txa = uitextarea(fig);

Set and Access Text Area Properties

Create a populated text area.

fig = uifigure;
txa = uitextarea(fig,...
                'Value', {'First Name Last Name';...
                'Address 1'; 'Address 2';'City, State'; 'Postal Code'});

Notice that the text area includes a scroll bar so that the app user can view the postal code.

Determine the current size of the text area.

size = txa.Position(3:4)

size =

   150    60

Increase the text area size so that the postal code displays without the use of a scroll bar.

txa.Position(3:4) = [155 75];

Scroll Text Area Programmatically

Scroll to the bottom of a text area programmatically.

Create a text area. Specify a size and long text for it.

fig = uifigure;
txa = uitextarea(fig);
txa.Position = [100 100 80 80];
txa.Value = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor.';

Scroll to the bottom of the text area.

scroll(txa,'bottom')

Code Response to Changed Text Area Value

Create a text area and two labels. When an app user types text and clicks outside the text area, a label thanks the app user for the input. If the app user removes the text and clicks outside the text area, the thank you text is removed.

Save the following code to comments.m on your MATLAB path. This code creates a figure window containing two labels and a text area. When an app user types text and clicks outside the text area, the ValueChangedFcn callback updates one of the labels to thank the user.

function comments
% Create figure window and components

fig = uifigure('Position',[500 500 430 275]);

label1 = uilabel(fig,...
    'Position',[100 164 100 15],...
    'Text','Enter Comments:');

label2 = uilabel(fig,...
    'Position',[100 75 175 15],...
    'Text','');

textarea = uitextarea(fig,...
    'Position',[100 100 150 60],...
    'ValueChangedFcn',@(textarea,event) textEntered(textarea, label2));

% Create ValueChangedFcn callback
    function textEntered(textarea,label2)
        val = textarea.Value;
        label2.Text = '';
        % Check each element of text area cell array for text
        for k = 1:length(val)
            if(~isempty(val{k}))
                label2.Text = 'Thank you for your comments!';
                break;
            end
        end
    end
end

Run comments, and type text in the text area field. Click outside the text area to trigger the callback.

Input Arguments

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 you do not specify a parent container, MATLAB calls the uifigure function to create a new Figure object that serves as the parent container.

Name-Value Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: 'Editable','off' specifies that the app user cannot change the text area text.

The properties listed here are a subset of the available properties. For the full list, see TextArea Properties.

Value — Value

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

Value, specified as a character vector, cell array of character vectors, string array, or 1-D categorical array. MATLAB can properly render formatted text, such as this:

cellArrayText{1} = sprintf('%s\n%s', 'Line 1', 'Line 2')
cellArrayText{2} = sprintf('%s\n%s', 'Line 3', 'Line 4')
textarea = uitextarea('Value',cellArrayText);

If you specify this property as a categorical array, MATLAB uses the values in the array, not the full set of categories.

If the text does not fit into the width of the text area, MATLAB wraps the text.

If there are too many rows to display in the text area, MATLAB adds a scroll bar.

Example: {'Joseph Welford'; 'Mary Reilly'; 'Roberta Silberlicht'}

ValueChangedFcn — Value changed callback

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

Value 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.

The callback executes when the user changes the text and either presses Tab or clicks outside the text area. It does not execute if the Value property changes programmatically.

This callback function can access specific information about the user’s interaction with the text area. MATLAB passes this information in a ValueChangedData 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.PreviousValue returns the previous value of the text area. The ValueChangedData object is not available to callback functions specified as character vectors.

The following table lists the properties of the ValueChangedData object.

Property	Value
Value	Value of text area after app user’s most recent interaction with it
PreviousValue	Value of text area before app user’s most recent interaction with it
Source	Component that executes the callback
EventName	'ValueChanged'

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

ValueChangingFcn — Value changing callback

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

Value changing 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.

This callback executes as follows:

• As the user types in the text area, the callback executes repeatedly.

• When the user presses Tab or clicks outside the text area, the callback executes.

If the text area value changes programmatically, then the callback does not execute.

This callback function can access specific information about the user’s interaction with the text area. MATLAB passes this information in a ValueChangingData 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.Value is the value in the text area that triggered the execution of the callback. The ValueChangingData object is not available to callback functions specified as character vectors.

Here are the properties of the ValueChangingData object:

Property	Description
Value	Value that triggered the execution of the callback
Source	Component that executes the callback
EventName	'ValueChanging'

The Value property of the TextArea object is not updated until the user either presses Tab or clicks outside the text area. However, you can get the text while the user is still typing by querying the Value property of the ValueChangingData object.

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

Position — Location and size of text area

[100 100 150 60] (default) | [left bottom width height]

Location and size of the text area relative to the parent, specified as the vector [left bottom width height]. This table describes each element in the vector.

Element	Description
left	Distance from the inner left edge of the parent container to the outer left edge of the text area
bottom	Distance from the inner bottom edge of the parent container to the outer bottom edge of the text area
width	Distance between the right and left outer edges of the text area
height	Distance between the top and bottom outer edges of the text area

All measurements are in pixel units.

The Position values are relative to the drawable area of the parent container. The drawable area is the area inside the borders of the container and does not include the area occupied by decorations such as a menu bar or title.

Example: [100 100 100 90]