java如何用按钮清除文本区域？

Question

这是我第一次使用Java。如何使用按钮清除文本区域中的文本？我的输入等代码如下：

        enter = new JButton("Enter");
        enter.setActionCommand("enter");
        enter.addActionListener(this);
        delete = new JButton("Clear");
        delete.setActionCommand("delete");
//      delete.addActionListener(questionarea.setText(""));
               
        //Create and set JPanels
        topPanel = new JPanel();
        deletePanel = new JPanel();
        bottomPanel = new JPanel();
        
        topPanel.setLayout(new GridLayout(1, 1));
        bottomPanel.setLayout(new GridLayout(1, 3));
        deletePanel.setLayout(new GridLayout(1, 3));
        
        //Area for user input
        questionarea = new JTextArea();
        questionarea.setFont(new Font("Silom", Font.PLAIN, 50));
        questionarea.setEditable(false);
        
        //Adding components to panel
        topPanel.add(questionarea, BorderLayout.CENTER);
        bottomPanel.add(enter);
        deletePanel.add(delete);
        
        //Adding panels to JFrame
        add(timerPanel);
        add(bottomPanel); 
        add(deletePanel);

我使用这里的文本区域输入数字来回答一个简单的加法或减法问题：

    public void generateRandomProblem()
    {       
    if(prob == 0)
    {
            opert = '+';
            Answer = A + B;
    }   
        else
        {
            opert = '-';
            Answer = A - B;
        }
               
        String q = "" + A + " " + opert + " " + B + " = ";
        questionarea.setText(q);
    }

Answer 1

您想将setText("")放入按钮侦听器中

delete = new JButton("Clear");
delete.addActionListener(new ActionListener() {

    @Override
    public void actionPerformed(ActionEvent e) {
        questionarea.setText("");
    }
});