JtextField 位置和编辑

java源码

package textfield;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;
public class JtextField extends JFrame {
	private JTextField textField;
	public JtextField() {
		initUi();
	}
	private void initUi() {
		setTitle("example");
		setLayout(new GridLayout(0, 1));
		textField = new JTextField("Left");
		textField.setHorizontalAlignment(JTextField.LEFT);
		add(textField);
		textField = new JTextField("Center");
		textField.setHorizontalAlignment(JTextField.CENTER);
		add(textField);
		textField = new JTextField("Right");
		textField.setHorizontalAlignment(JTextField.RIGHT);
		add(textField);
		textField = new JTextField("Leading");
		textField.setHorizontalAlignment(JTextField.LEADING);
		add(textField);
		textField = new JTextField("Trailing");
		textField.setHorizontalAlignment(JTextField.TRAILING);
		add(textField);
		add(new JButton("--------------------------------------------"));
		textField = new JTextField(15);
		JButton jbtnCut = new JButton("Cut");
		JButton jbtnPaste = new JButton("Paste");
		JButton jbtnCopy = new JButton("Copy");
		jbtnCut.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent le) {
				textField.cut();
				update();
			}
		});
		jbtnPaste.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent le) {
				textField.paste();
				update();
			}
		});
		jbtnCopy.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent le) {
				textField.copy();
				update();
			}
		});
		textField.addCaretListener(new CaretListener() {
			public void caretUpdate(CaretEvent ce) {
				update();
			}
		});
		add(textField);
		add(jbtnCut);
		add(jbtnPaste);
		add(jbtnCopy);
	}
	private void update() {
		System.out.println("All text: " + textField.getText());
		if (textField.getSelectedText() != null)
			System.out.println("Selected text: " + textField.getSelectedText());
		else
			System.out.println("Selected text: ");
	}
	private void display() {
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.pack();
		this.setSize(250, (int) this.getSize().getHeight());
		this.setVisible(true);
	}
	public static void main(final String args[]) {
		new JtextField().display();
	}
}

效果图：