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我有一個應該是「佈局」示例。一個簡單的程序，當用戶點擊按鈕時，它會改變框架的佈局。 它工作正常，直到我現在添加了最後兩個其他框架時，我運行它的按鈕丟失。我已檢查並檢查並找不到問題。有人可以幫忙嗎？框架按鈕不可見
public class FrameLayouts {
public static void main (String [] args){
final JFrame frame1 = new JFrame("FlowLayout");
final JFrame frame2 = new JFrame("GridLayout");
final JFrame frame3 = new JFrame("BorderLayout");
frame1.setVisible(true);
frame2.setVisible(false);
frame3.setVisible(false);
frame1.setLocationRelativeTo(null);
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.setSize(500,500);
frame1.setLayout(new FlowLayout());
JButton button1 = new JButton ("Grid Layout");
JButton button2 = new JButton ("Border Layout");
JButton button3 = new JButton ("Flow Layout");
JButton button4 = new JButton ("EXTRA");
JButton button5 = new JButton ("EXTRA");
frame1.add(button4);
frame1.add(button1);
frame1.add(button2);
frame1.add(button3);
frame1.add(button5);
frame1.pack();
frame2.add(button4);
frame2.add(button1);
frame2.add(button2);
frame2.add(button3);
frame2.add(button5);
frame2.pack();
frame3.add(button4, BorderLayout.NORTH);
frame3.add(button1, BorderLayout.CENTER);
frame3.add(button2, BorderLayout.SOUTH);
frame3.add(button3, BorderLayout.EAST);
frame3.add(button5, BorderLayout.WEST);
frame3.pack();
button1.addActionListener(new ActionListener(){
public void actionPerformed (ActionEvent e){
frame2.setVisible(true);
frame2.setLocationRelativeTo(null);
frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame2.setSize(500,500);
frame2.setLayout(new GridLayout(2,3));
frame3.setVisible(false);
frame1.setVisible(false);
}
});
button2.addActionListener(new ActionListener(){
@Override
public void actionPerformed(ActionEvent e) {
frame3.setVisible(true);
frame3.setLocationRelativeTo(null);
frame3.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame3.setSize(500,500);
frame3.setLayout(new BorderLayout(5,5));
frame1.setVisible(false);
frame2.setVisible(false);
}
});
button3.addActionListener(new ActionListener(){
public void actionPerformed (ActionEvent e){
frame1.setVisible(true);
frame1.setLocationRelativeTo(null);
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.setSize(500,500);
frame1.setLayout(new FlowLayout());
frame2.setVisible(false);
frame3.setVisible(false);
}
});
}
}