比如这个代码,运行时只能弹出一个空得frame,只有点击了textfield得位置,它才显示出来,我是在mac下编的,且有用windowbuilder,再自己修改
public KeyFrame() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
setVisible(true);
tf = new JTextField();
tf.addKeyListener(new KeyMonitor());
tf.setBounds(81, 75, 294, 133);
contentPane.add(tf);
tf.setColumns(10);
}