Java Tutorial/Swing/JTextArea
Содержание
- 1 Append some text to JTextArea
- 2 Copy selected text from one text area to another
- 3 Customizing a JTextArea Look and Feel
- 4 Delete the first 5 characters
- 5 Enumerate the content elements with a ElementIterator
- 6 Enumerating the Lines in a JTextArea Component
- 7 Hello in Japanese
- 8 Highlight of discontinous string
- 9 Insert some text after the 5th character
- 10 JTextArea: for multiple-line input.
- 11 Modifying Text in a JTextArea Component
- 12 Moving the Focus with the TAB Key in a JTextArea Component
- 13 Replace the first 3 characters with some text
- 14 Set font for I18N to JTextArea
- 15 Setting JTextArea Line Wrap and Wrap Style
- 16 Setting text drag in a JTextArea
- 17 Setting the Tab Size of a JTextArea Component
- 18 Using Actions with Text Components: JTextArea
- 19 Using JTextArea
Append some text to JTextArea
<source lang="java">
import javax.swing.JTextArea; public class Main {
public static void main(String[] argv) {
JTextArea ta = new JTextArea("Initial Text");
ta.append("some text");
}
}</source>
Copy selected text from one text area to another
<source lang="java">
import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.Box; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTextArea; public class Main extends JFrame {
private JTextArea t1 = new JTextArea("this is a test", 10, 15), t2;
private JButton copy = new JButton("Copy >>>");
public Main() {
Box b = Box.createHorizontalBox();
b.add(new JScrollPane(t1));
copy.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
t2.setText(t1.getSelectedText());
}
});
b.add(copy);
t2 = new JTextArea(10, 15);
t2.setEditable(false);
b.add(new JScrollPane(t2));
add(b);
setSize(425, 200);
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String args[]) {
new Main();
}
}</source>
Customizing a JTextArea Look and Feel
Property StringObject TypeTextArea.actionMapActionMapTextArea.backgroundColorTextArea.borderBorderTextArea.caretAspectRatioNumberTextArea.caretBlinkRateIntegerTextArea.caretForegroundColorTextArea.focusInputMapInputMapTextArea.fontFontTextArea.foregroundColorTextArea.inactiveForegroundColorTextArea.keyBindingsKeyBinding[ ]TextArea.marginInsetsTextArea.selectionBackgroundColorTextArea.selectionForegroundColorTextAreaUIString
Delete the first 5 characters
<source lang="java">
import javax.swing.JTextArea; public class Main {
public static void main(String[] argv) {
JTextArea ta = new JTextArea("Initial Text");
int start = 0;
int end = 5;
ta.replaceRange(null, start, end);
}
}</source>
Enumerate the content elements with a ElementIterator
<source lang="java">
import javax.swing.JTextArea; import javax.swing.text.Document; import javax.swing.text.Element; import javax.swing.text.ElementIterator; public class Main {
public static void main(String[] argv) throws Exception {
JTextArea textArea = new JTextArea("word1 word2\nword3\nword4");
Document doc = textArea.getDocument();
ElementIterator it = new ElementIterator(doc.getDefaultRootElement());
Element e;
while ((e = it.next()) != null) {
if (e.isLeaf()) {
int rangeStart = e.getStartOffset();
int rangeEnd = e.getEndOffset();
String line = textArea.getText(rangeStart, rangeEnd - rangeStart);
System.out.println(line);
}
}
}
}</source>
Enumerating the Lines in a JTextArea Component
<source lang="java">
import javax.swing.JTextArea; import javax.swing.text.Element; public class Main {
public static void main(String[] argv) throws Exception {
JTextArea textArea = new JTextArea("word1 word2\nword3\nword4");
Element paragraph = textArea.getDocument().getDefaultRootElement();
int contentCount = paragraph.getElementCount();
for (int i = 0; i < contentCount; i++) {
Element e = paragraph.getElement(i);
int rangeStart = e.getStartOffset();
int rangeEnd = e.getEndOffset();
String line = textArea.getText(rangeStart, rangeEnd - rangeStart);
System.out.println(line);
}
}
}</source>
Hello in Japanese
<source lang="java">
import java.awt.Font; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTextArea; public class HelloInJapanese extends JPanel {
static JFrame frame;
static String helloInJapanese = "\u4eca\u65e5\u306f.";
public HelloInJapanese(String characters) {
JTextArea area = new JTextArea(characters, 2, 30);
area.setFont(new Font("Bitstream Cyberbit", Font.PLAIN, 20));
area.setLineWrap(true);
JScrollPane scrollpane = new JScrollPane(area);
add(scrollpane);
}
public static void main(String argv[]) {
HelloInJapanese japanesePanel = new HelloInJapanese(helloInJapanese);
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add("Center", japanesePanel);
frame.pack();
frame.setVisible(true);
}
}</source>
Highlight of discontinous string
<source lang="java">
import javax.swing.JTextArea; import javax.swing.text.DefaultHighlighter; import javax.swing.text.Highlighter; public class Main {
public static void main(String args[]) {
JTextArea area = new JTextArea(5, 20);
area.setText("this is a test.");
String charsToHighlight = "aeiouAEIOU";
Highlighter h = area.getHighlighter();
h.removeAllHighlights();
String text = area.getText().toUpperCase();
for (int i = 0; i < text.length(); i += 1) {
char ch = text.charAt(i);
if (charsToHighlight.indexOf(ch) >= 0)
try {
h.addHighlight(i, i + 1, DefaultHighlighter.DefaultPainter);
} catch (Exception ble) {
}
}
}
}</source>
Insert some text after the 5th character
<source lang="java">
import javax.swing.JTextArea; public class Main {
public static void main(String[] argv) {
JTextArea ta = new JTextArea("Initial Text");
int pos = 5;
ta.insert("some text", pos);
}
}</source>
JTextArea: for multiple-line input.
Put JTextArea within a JScrollPane to allow a user to properly scroll through the contents of a JTextArea.
<source lang="java">
JTextArea textArea = new JTextArea(); JScrollPane scrollPane = new JScrollPane(textArea); content.add(scrollPane);</source>
Modifying Text in a JTextArea Component
<source lang="java">
import javax.swing.JTextArea; public class Main {
public static void main(String[] argv) {
// Create the text area
JTextArea ta = new JTextArea("Initial Text");
// Insert some text at the beginning
int pos = 0;
ta.insert("some text", pos);
}
}</source>
Moving the Focus with the TAB Key in a JTextArea Component
<source lang="java">
import java.awt.ruponent; import java.awt.event.ActionEvent; import javax.swing.AbstractAction; import javax.swing.Action; import javax.swing.JTextArea; public class Main {
public static void main(String[] argv) throws Exception {
JTextArea component = new JTextArea();
NextFocusAction nextFocusAction = new NextFocusAction();
PrevFocusAction prevFocusAction = new PrevFocusAction();
component.getActionMap().put(nextFocusAction.getValue(Action.NAME), nextFocusAction);
component.getActionMap().put(prevFocusAction.getValue(Action.NAME), prevFocusAction);
}
} class NextFocusAction extends AbstractAction{
public NextFocusAction(){
super("Move Focus Forwards");
}
public void actionPerformed(ActionEvent evt) {
((Component) evt.getSource()).transferFocus();
}
} class PrevFocusAction extends AbstractAction {
public PrevFocusAction(){
super("Move Focus Backwards");
}
public void actionPerformed(ActionEvent evt) {
((Component) evt.getSource()).transferFocusBackward();
}
}</source>
Replace the first 3 characters with some text
<source lang="java">
import javax.swing.JTextArea; public class Main {
public static void main(String[] argv) {
JTextArea ta = new JTextArea("Initial Text");
int start = 0;
int end = 3;
ta.replaceRange("new text", start, end);
}
}</source>
Set font for I18N to JTextArea
<source lang="java">
import java.awt.Font; import java.awt.GraphicsEnvironment; import javax.swing.JFrame; import javax.swing.JTextArea; public class JTextAreaI18N extends JFrame {
String davidMessage = "\u05E9\u05DC\u05D5\u05DD \u05E2\u05D5\u05DC\u05DD";
public JTextAreaI18N() {
GraphicsEnvironment.getLocalGraphicsEnvironment();
JTextArea textArea = new JTextArea(davidMessage);
textArea.setFont(new Font("LucidaSans", Font.PLAIN, 40));
this.getContentPane().add(textArea);
textArea.setVisible(true);
}
public static void main(String[] args) {
JFrame frame = new JTextAreaI18N();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
}</source>
Setting JTextArea Line Wrap and Wrap Style
<source lang="java">
JTextArea textArea = new JTextArea("..."); textArea.setLineWrap(true); textArea.setWrapStyleWord(true); JScrollPane scrollPane = new JScrollPane(textArea);</source>
Setting text drag in a JTextArea
<source lang="java">
import java.awt.BorderLayout; import javax.swing.JFrame; import javax.swing.JTextArea; import javax.swing.JTextField; public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame();
JTextArea textarea = new JTextArea();
textarea.setDragEnabled(true);
textarea.setText("Drag target");
frame.getContentPane().add(BorderLayout.CENTER, textarea);
JTextField textarea1 = new JTextField();
textarea1.setText("Drop target");
frame.getContentPane().add(BorderLayout.SOUTH, textarea1);
frame.setSize(500, 300);
frame.setVisible(true);
frame.setLocation(100, 100);
}
}</source>
Setting the Tab Size of a JTextArea Component
<source lang="java">
import java.awt.Font; import javax.swing.JTextArea; public class Main {
public static void main(String[] argv) {
JTextArea textarea = new JTextArea();
// Get the default tab size
int tabSize = textarea.getTabSize(); // 8
// Change the tab size
tabSize = 4;
textarea.setTabSize(tabSize);
Font font = textarea.getFont();
System.out.println(font);
}
}</source>
Using Actions with Text Components: JTextArea
<source lang="java">
import java.util.Arrays; import java.util.ruparator; import javax.swing.Action; import javax.swing.JTextArea; import javax.swing.text.JTextComponent; public class ListActionsJTextArea {
public static void main(String args[]) {
JTextComponent component = new JTextArea();
// Process action list
Action actions[] = component.getActions();
// Define comparator to sort actions
Comparator<Action> comparator = new Comparator<Action>() {
public int compare(Action a1, Action a2) {
String firstName = (String) a1.getValue(Action.NAME);
String secondName = (String) a2.getValue(Action.NAME);
return firstName.rupareTo(secondName);
}
};
Arrays.sort(actions, comparator);
int count = actions.length;
System.out.println("Count: " + count);
for (int i = 0; i < count; i++) {
System.out.printf("%28s : %s\n",actions[i].getValue(Action.NAME),actions[i].getClass().getName());
}
}
}</source>
Count: 53
beep : javax.swing.text.DefaultEditorKit$BeepAction
caret-backward : javax.swing.text.DefaultEditorKit$NextVisualPositionAction
caret-begin : javax.swing.text.DefaultEditorKit$BeginAction
caret-begin-line : javax.swing.text.DefaultEditorKit$BeginLineAction
caret-begin-paragraph : javax.swing.text.DefaultEditorKit$BeginParagraphAction
caret-begin-word : javax.swing.text.DefaultEditorKit$BeginWordAction
caret-down : javax.swing.text.DefaultEditorKit$NextVisualPositionAction
caret-end : javax.swing.text.DefaultEditorKit$EndAction
caret-end-line : javax.swing.text.DefaultEditorKit$EndLineAction
caret-end-paragraph : javax.swing.text.DefaultEditorKit$EndParagraphAction
caret-end-word : javax.swing.text.DefaultEditorKit$EndWordAction
caret-forward : javax.swing.text.DefaultEditorKit$NextVisualPositionAction
caret-next-word : javax.swing.text.DefaultEditorKit$NextWordAction
caret-previous-word : javax.swing.text.DefaultEditorKit$PreviousWordAction
caret-up : javax.swing.text.DefaultEditorKit$NextVisualPositionAction
copy-to-clipboard : javax.swing.text.DefaultEditorKit$CopyAction
cut-to-clipboard : javax.swing.text.DefaultEditorKit$CutAction
default-typed : javax.swing.text.DefaultEditorKit$DefaultKeyTypedAction
delete-next : javax.swing.text.DefaultEditorKit$DeleteNextCharAction
delete-previous : javax.swing.text.DefaultEditorKit$DeletePrevCharAction
dump-model : javax.swing.text.DefaultEditorKit$DumpModelAction
insert-break : javax.swing.text.DefaultEditorKit$InsertBreakAction
insert-content : javax.swing.text.DefaultEditorKit$InsertContentAction
insert-tab : javax.swing.text.DefaultEditorKit$InsertTabAction
page-down : javax.swing.text.DefaultEditorKit$VerticalPageAction
page-up : javax.swing.text.DefaultEditorKit$VerticalPageAction
paste-from-clipboard : javax.swing.text.DefaultEditorKit$PasteAction
select-all : javax.swing.text.DefaultEditorKit$SelectAllAction
select-line : javax.swing.text.DefaultEditorKit$SelectLineAction
select-paragraph : javax.swing.text.DefaultEditorKit$SelectParagraphAction
select-word : javax.swing.text.DefaultEditorKit$SelectWordAction
selection-backward : javax.swing.text.DefaultEditorKit$NextVisualPositionAction
selection-begin : javax.swing.text.DefaultEditorKit$BeginAction
selection-begin-line : javax.swing.text.DefaultEditorKit$BeginLineAction
selection-begin-paragraph : javax.swing.text.DefaultEditorKit$BeginParagraphAction
selection-begin-word : javax.swing.text.DefaultEditorKit$BeginWordAction
selection-down : javax.swing.text.DefaultEditorKit$NextVisualPositionAction
selection-end : javax.swing.text.DefaultEditorKit$EndAction
selection-end-line : javax.swing.text.DefaultEditorKit$EndLineAction
selection-end-paragraph : javax.swing.text.DefaultEditorKit$EndParagraphAction
selection-end-word : javax.swing.text.DefaultEditorKit$EndWordAction
selection-forward : javax.swing.text.DefaultEditorKit$NextVisualPositionAction
selection-next-word : javax.swing.text.DefaultEditorKit$NextWordAction
selection-page-down : javax.swing.text.DefaultEditorKit$VerticalPageAction
selection-page-left : javax.swing.text.DefaultEditorKit$PageAction
selection-page-right : javax.swing.text.DefaultEditorKit$PageAction
selection-page-up : javax.swing.text.DefaultEditorKit$VerticalPageAction
selection-previous-word : javax.swing.text.DefaultEditorKit$PreviousWordAction
selection-up : javax.swing.text.DefaultEditorKit$NextVisualPositionAction
set-read-only : javax.swing.text.DefaultEditorKit$ReadOnlyAction
set-writable : javax.swing.text.DefaultEditorKit$WritableAction
toggle-componentOrientation : javax.swing.text.DefaultEditorKit$ToggleComponentOrientationAction
unselect : javax.swing.text.DefaultEditorKit$UnselectAction
Using JTextArea
<source lang="java">
import java.awt.Dimension; import java.awt.FlowLayout; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTextArea; public class JTextAreaTest {
public static void main(String[] args) {
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame frame = new JFrame("JTextArea Test");
frame.setLayout(new FlowLayout());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
String text = "A JTextArea object represents a multiline area for displaying text. "
+ "You can change the number of lines that can be displayed at a time, "
+ "as well as the number of columns. You can wrap lines and words too. "
+ "You can also put your JTextArea in a JScrollPane to make it scrollable.";
JTextArea textAreal = new JTextArea(text, 5, 10);
textAreal.setPreferredSize(new Dimension(100, 100));
JTextArea textArea2 = new JTextArea(text, 5, 10);
textArea2.setPreferredSize(new Dimension(100, 100));
JScrollPane scrollPane = new JScrollPane(textArea2, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
textAreal.setLineWrap(true);
textArea2.setLineWrap(true);
frame.add(textAreal);
frame.add(scrollPane);
frame.pack();
frame.setVisible(true);
}
}</source>
