在Java中动态生成按钮 [英] Dynamic generation of buttons in Java

问题描述

我正在尝试动态生成一个表单。基本上，我想加载要购买的项目列表，并为每个项目生成一个按钮。我可以确认这些按钮是使用调试器生成的，但它们没有被显示。这是在 JPanel 的子类之内：

  private void generate（） {
 JButton b = new JButton（height test）; 
 int btnHeight = b.getPreferredSize（）。height; 
 int pnlHeight = this.getPreferredSize（）。height; 
 int numButtons = pnlHeight / btnHeight; 
 
 setLayout（new GridLayout（numButtons，1））; 
 
迭代器<饮料> it = DrinkMenu.iterator（）; （int i = 0; i< = numButtons; ++ i）{
 if（！it.hasNext（））{
 break; 
 
 
} 
 final喝dr = it.next（）; 
 b = new DrinkBut​​ton（dr）; 
 b.addActionListener（new ActionListener（）{
 public void actionPerformed（ActionEvent e）{
 order.addDrink（dr）; 
}}） 
 add（b）; 
} 
 revalidate（）; 
} 
  

DrinkBut​​ton 是一个 JButton 的子类。任何想法？

解决方案

在我的电脑上工作...

  public class Panel扩展JPanel {
 
 public Panel（）{
 setLayout（new java.awt.GridLayout（4，4））; （int i = 0; i <16; ++ i）{
 JButton b = new JButton（String.valueOf（i））; 
 
 b.addActionListener（new java.awt.event.ActionListener（）{
 public void actionPerformed（java.awt.event.ActionEvent e）{
 // ... 
 } 
}）; 
 add（b）; 
} 
} 
 
 public static void main（String [] args）{
 SwingUtilities.invokeLater（new Runnable（）{
 @Override 
 public void run（）{
 JFrame frame = new JFrame（）; 
 frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）; 
 frame.setSize（new Dimension（300，300））; 
 frame.add（new Panel（））; 
 frame.setVisible（true）; 
} 
}）; 
} 
} 
  

据我所知，您的版本一直工作虽然我不得不删除你的喝酒代码。从这个例子开始（它显示漂亮的4x4网格的按钮），并确定你的代码有什么问题。

I am trying to dynamically generate a form. Basically, I want to load a list of items for purchase, and generate a button for each. I can confirm that the buttons are being generated with the debugger, but they aren't being displayed. This is inside a subclass of JPanel:

private void generate() {
    JButton b = new JButton("height test");
    int btnHeight = b.getPreferredSize().height;
    int pnlHeight = this.getPreferredSize().height;
    int numButtons = pnlHeight / btnHeight;

    setLayout(new GridLayout(numButtons, 1));

    Iterator<Drink> it = DrinkMenu.iterator();

    for (int i = 0; i <= numButtons; ++i) {
        if (!it.hasNext()) {
            break;
        }
        final Drink dr = it.next();
        b = new DrinkButton(dr);
        b.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                order.addDrink(dr);
        }});
        add(b);
    }
    revalidate();
}

DrinkButton is a subclass of JButton. Any ideas?

解决方案

Works on my computer...

public class Panel extends JPanel {

    public Panel() {
        setLayout(new java.awt.GridLayout(4, 4));
        for (int i = 0; i < 16; ++i) {
            JButton b = new JButton(String.valueOf(i));
            b.addActionListener(new java.awt.event.ActionListener() {
                public void actionPerformed(java.awt.event.ActionEvent e) {
                    //...
                }
            });
            add(b);
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable(){
            @Override
            public void run(){
                JFrame frame = new JFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setSize(new Dimension(300, 300));
                frame.add(new Panel());
                frame.setVisible(true);
            }
        });
    }
}

As far as I remember your version was working as well, although I had to remove your "drinking" code. Start from this example (it shows nice 4x4 grid of buttons) and determine what is wrong with your code.

这篇关于在Java中动态生成按钮的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！