关于下拉框和列表框,i以及密码框和文本域的使用

首先是下拉框

public class JComboBoxDemo extends JFrame {
    public JComboBoxDemo(){
        Container container = this.getContentPane();
        JComboBox box = new JComboBox();//首先是记住名字
        box.addItem(null);//添加下拉选项的属性是addItem
        box.addItem("1");
        box.addItem("2");
        box.addItem("3");
        JPanel jPanel = new JPanel();
        jPanel.setLayout(new BorderLayout());
        jPanel.add(box);
        container.add(box);
        this.setVisible(true);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        this.setBounds(100,100,400,600);
    }

    public static void main(String[] args) {
        new JComboBoxDemo();
    }

}

然后是关于列表框的使用

public class JComboBoxDemo extends JFrame {
    public JComboBoxDemo(){
        Container container = this.getContentPane();
        Vector vector = new Vector<>();//创建一个vector容器；
        JList jList = new JList(vector);//JList中可以放容器(动态),也可以放一些静态的数组啥的.
        vector.add("1");
        vector.add(2);
        vector.add(3);
        container.add(jList);
        this.setVisible(true);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        this.setBounds(100,100,400,600);
    }

    public static void main(String[] args) {
        new JComboBoxDemo();
    }

}

下面是密码框的使用.

public class JComboBoxDemo extends JFrame {
    public JComboBoxDemo(){
        Container container = this.getContentPane();
        Vector vector = new Vector<>();
        JList jList = new JList(vector);
        vector.add("1");
        vector.add(2);
        vector.add(3);
        container.add(jList);
        this.setVisible(true);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        this.setBounds(100,100,400,600);
    }

    public static void main(String[] args) {
        new JComboBoxDemo();
    }

}

还要区别textField和textArea的区别