如何通过另一个JFrame修改JFrame？

Question

I have two JFrames A, and B. B has a textArea. I want to add some text to that TextArea in B by clicking a button in A. here is my code:

JButton btn = new JButton("Text");
btnButton_1.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        b.textArea.setText("Button clicked");
    }
});
btnButton_1.setBounds(10, 45, 89, 23);
frmA.getContentPane().add(btnButton_1);

• b is object of class B
• textArea is JTextArea variable name in class B

Answer 1

Use repaint() method of components.

JButton btn = new JButton("Text");
        btnButton_1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                b.textArea.setText("Button clicked");
                b.frameB.repaint();
            }
        });
        btnButton_1.setBounds(10, 45, 89, 23);
        frmA.getContentPane().add(btnButton_1);