Question

我有一个JButton变量用于创建不同数字的不同按钮

JButton numb;
numb = new JButton("7");
    c.fill = GridBagConstraints.HORIZONTAL;
    c.ipadx = 30;
    c.ipady = 30;
    c.gridx = 0;
    c.gridy = 3;
    c.gridwidth = 1;
    displayPanel.add(numb, c);
    numb.setFont(new Font("arial",Font.BOLD,20));
    numb.addActionListener(this);

    numb = new JButton("8");
    c.fill = GridBagConstraints.HORIZONTAL;
    c.ipadx = 30;
    c.ipady = 30;
    c.gridx = 1;
    c.gridy = 3;
    c.gridwidth = 1;
    displayPanel.add(numb, c);
    numb.setFont(new Font("arial",Font.BOLD,20));
     numb.addActionListener(this);

    numb = new JButton("9");
    c.fill = GridBagConstraints.HORIZONTAL;
    c.ipadx = 30;
    c.ipady = 30;
    c.gridx = 2;
    c.gridy = 3;
    c.gridwidth = 1;
    displayPanel.add(numb, c);
    numb.setFont(new Font("arial",Font.BOLD,20));
    numb.addActionListener(this);

喜欢这样

当点击我的按钮时，我会从按下的按钮中读取文本

我的actionPerformed看起来像这样

public void actionPerformed(ActionEvent e) {
    // add your event handling code here
    if (e.getSource()==numb){

        String button = (String)e.getActionCommand();

        display.setText(button); 

        System.out.println(button);

    }else if (e.getSource()==opButton){

        System.out.println(button);
    }

}

Answer 1

你可以打印出点击的按钮文本，如下所示：

JButton button = (JButton) e.getSource();
String text = button.getText();
display.setText(text);
System.out.println(text);

......但是你要做的事情并不是很清楚。特别是，您已经在几个不同的时间重新分配了numb的值 - 它无法引用这些按钮的所有。您可能希望为所有按钮提供一个通用操作命令，例如“数字”。然后你可以使用：

private static final String DIGIT_COMMAND = "digit";

// Assign the action command of each button as DIGIT_COMMAND...

...

public void actionPerformed(ActionEvent e) {
    if (DIGIT_COMMAND.equals(e.getActionCommand()) {
        JButton button = (JButton) e.getSource();
        String text = button.getText();
        display.setText(text);
        System.out.println(text);
    } else {
        // Handle other commands
    }
}

从一个变量多按钮读取文本

1 个答案: