问题
For my case, I want to insert text inside JTextArea by number line.
For e.g
name : andy
birth : jakarta, 1 jan 1990
number id : 01011990 01
age : 26
study : Informatics engineering
So, I want to insert text in last position in line 3.
I think I can use:
jTextArea.getDocument.insertString(3," my text here".null);
but it doesn't work.
So, I wish my output to be like this.
name : andy
birth : jakarta, 1 jan 1990
number id : 01011990 01 my text here
age : 26
study : Informatics engineering
回答1:
You can use the Element#getElement(int) method:
import java.awt.*;
import java.awt.event.*;
import java.util.Optional;
import javax.swing.*;
import javax.swing.text.*;
public class ElementEndOffsetTest {
public JComponent makeUI() {
String str = "name : andy\n"
+ "birth : jakarta, 1 jan 1990\n"
+ "number id : 01011990 01\n"
+ "age : 26\n"
+ "study : Informatics engineering\n";
JTextArea textArea = new JTextArea(str);
textArea.setEditable(false);
JPanel p = new JPanel(new BorderLayout());
p.add(new JScrollPane(textArea));
p.add(new JButton(new AbstractAction("add") {
@Override public void actionPerformed(ActionEvent e) {
Document doc = textArea.getDocument();
Element root = doc.getDefaultRootElement();
Optional.ofNullable(root.getElement(2)).ifPresent(el -> {
try {
doc.insertString(el.getEndOffset() - 1, " my text here", null);
} catch (BadLocationException ex) {
ex.printStackTrace();
}
});
}
}), BorderLayout.SOUTH);
return p;
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> {
JFrame f = new JFrame();
f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
f.getContentPane().add(new ElementEndOffsetTest().makeUI());
f.setSize(320, 240);
f.setLocationRelativeTo(null);
f.setVisible(true);
});
}
}
来源:https://stackoverflow.com/questions/34738025/java-inserting-text-using-jtextarea-by-number-line