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<span id=BreadCrumbs> <a href=../../index.html target=_top>Home Page</a> > <a href=../index.html target=_top>Creating a GUI with JFC/Swing</a> > <a href=index.html target=_top>Using Swing Components</a> </span> <div class=NavBit> <a target=_top href=table.html>« Previous</a> • <a target=_top href=../TOC.html>Trail</a> • <a target=_top href=textfield.html>Next »</a> </div> <div id=PageTitle>How to Use Text Areas</div> <blockquote>The<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/JTextArea.html"><code>JTextArea</code></a> classprovides a component thatdisplays multiple lines of text,optionally allowing the user to edit the text.If you need to obtain only one line of input from the user,you should use a <a href="textfield.html">text field</a> instead.If you want the text area to display its text using multiple fonts or other styles,you should use an<a href="editorpane.html">editor pane or text pane</a> instead.If the displayed texthas a limited length and is never edited by the user,consider using a <a href="label.html">label</a> instead.<p>Many of the Tutorial's examples use uneditable text areasto display program output.Here is a picture of onethat lets you enter text using a text field(at the top)and then appends the entered text to a text area(underneath).<p><center><IMG SRC="../../figures/uiswing/components/TextDemoSwing.png" WIDTH="246" HEIGHT="152" ALIGN="BOTTOM" ALT="A snapshot of TextDemo"></center></p><p>You can<a href="http://java.sun.com/docs/books/tutorialJWS/uiswing/components/examples/TextDemo.jnlp">run TextDemo</a> (it requires release 6) using<a class="TutorialLink" target="_top" href="../../information/javawebstart.html">Java<sup><font size=-2>TM</font></sup> Web Start</a>.The source code is in<a class="SourceLink" target="_blank" href="examples/TextDemo.java"><code>TextDemo.java</code></a>.Here's the codethat creates and initializes the text area:<blockquote><pre>textArea = new JTextArea(5, 20);JScrollPane scrollPane = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);textArea.setEditable(false);</pre></blockquote>The two arguments to the <code>JTextArea</code> constructorare hints as to the number of rows and columns, respectively,the text area should display.The scroll pane that contains the text areapays attention to these hints when determining how big the scroll pane should be.<p>Without the creation of the scroll pane,the text area would not automatically scroll.The <code>JScrollPane</code> constructor shown in the preceding snippetsets up the text area for viewing in a scroll pane,and specifies that the scroll pane's scroll bars should both always be visible.See <a href="scrollpane.html">How to Use Scroll Panes</a>if you want further information.<p>By default, text areas are editable.The code <code>setEditable(false)</code> makes the text area uneditable.It is still selectableand the user can copy data from it,but the user can't change the text area's contents directly.<p>The following code adds text to the text area.Note that the text system uses the '\n' characterinternally to represent newlines;for details,see the API documentation for<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/text/DefaultEditorKit.html"><code>DefaultEditorKit</code></a>.<blockquote><pre>⌨️ 快捷键说明
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