java - 如何使用按钮按下操作在面板中显示图像

Question

我想通过按按钮在面板上显示图像。我创建了一些代码

JButton btnNewButton = new JButton("next");
    btnNewButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            if(i<files1.length){
                BufferedImage bi;
                try {
                    bi = ImageIO.read(new File(""+files1[i]));
                    System.out.println(files1[i]);
                    JLabel label = new JLabel(new ImageIcon(bi));
                    panel_1.add(label);
                    panel_1.repaint();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            else
                System.out.println("end of picture");
            i++;
        }
    });

但是单击按钮后图像不显示。

Answer 1

But after click button image doesn't show.

看起来您缺少 revalidate()。将组件添加到可见 GUI 时的基本代码是:

panel.add(....);
panel.revalidate(); // to invoke the layout manager
panel.repaint();