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 object created using the uifigure function or one of its child containers.

txa = uitextarea(___,Name,Value) specifies TextArea properties using one or more name-value arguments. For example, uitextarea("Value","Comments") creates a text area that shows the text Comments. Use this option with any of the input argument combinations in the previous syntaxes.

Examples

Create Text Area

Create a text area in a UI figure.

fig = uifigure;
txa = uitextarea(fig);

Create Text Area with Placeholder Text

Create a text area in a UI figure. Specify placeholder text to describe the expected input. The placeholder text shows only when the text area is empty.

fig = uifigure;
txa = uitextarea(fig,"Placeholder","Enter feedback");

Set and Access Text Area Properties

Create a populated text area in a UI figure.

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 width and height of the text area by querying the third and fourth values of the Position property.

size = txa.Position(3:4)

size = 1×2

   150    60

Increase the text area size so that all of the content is visible without the use of a scroll bar.

txa.Position(3:4) = [155 80];

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 an app that enables a button when an app user enters text in a text area.

In a file named textAreaApp.m, write a function that implements the app:

• Create a UI figure and a grid layout manager to lay out the app.

• Create a label, text area, and button in the grid layout manager.

• Write a callback function named textEntered that enables a button when there is text in the text area, and assign the function to the ValueChangedFcn callback property of the text area. For more information about callbacks, see Create Callbacks for Apps Created Programmatically.

function textAreaApp
fig = uifigure;
g = uigridlayout(fig,[3 3]);
g.RowHeight = {'fit','fit','fit'};
g.ColumnWidth = {'1x','fit','1x'};

lbl = uilabel(g,"Text","Enter Comments:");
lbl.Layout.Row = 1;
lbl.Layout.Column = 2;
txa = uitextarea(g);
txa.Layout.Row = 2;
txa.Layout.Column = 2;
btn = uibutton(g,"Text","Submit","Enable","off");
btn.Layout.Row = 3;
btn.Layout.Column = 2;

txa.ValueChangedFcn = @(src,event) textEntered(src,event,btn);
end

function textEntered(src,event,btn)
val = src.Value;
btn.Enable = "off";
% Check each element of text area cell array for text
for k = 1:length(val)
    if ~isempty(val{k})
        btn.Enable = "on";
        break
    end
end
end

Run the textAreaApp function. Enter some text in the text area, then click outside the text area to enable the Submit button.

Input Arguments

parent — Parent container

Figure object (default) | Tab object | Panel 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 pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: uitextarea(Editable="off") specifies that the app user cannot change the text area text.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: uitextarea("Editable","off") specifies that the app user cannot change the text area text.

Note

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

Value — Value

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

Value, specified as a character vector, string scalar, cell array of character vectors, string array, or 1-D categorical array. To display multiple lines of text, specify Value as an array. Each element in the array represents a separate line of text.

txt = ["Line 1"; "Line 2"; "Line 3"; "Line 4"];
textarea = uitextarea("Value",txt);

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 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.

Note

Avoid updating the Value property of the TextArea object from within its own ValueChangingFcn callback, as this might result in unexpected behavior. To update the text area value in response to user input, use a ValueChangedFcn callback instead.

For more information about writing callbacks, see 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]

Version History

Introduced in R2016a

R2021b: Program response while a user is typing

Create a ValueChangingFcn callback to program your app to respond when a user is typing in a text area. The callback function executes repeatedly while the user types.

R2021a: Specify placeholder text

Provide a short hint that describes the expected text area input by using the Placeholder property.

For more information, see TextArea.

R2020b: Toggle text wrapping

Use the WordWrap property to toggle text wrapping. When the WordWrap property is 'on' (the default), the UI component breaks the text into new lines so that each line fits horizontally within the component. When the property is set to 'off', the text does not wrap.

For more information, see TextArea.