Question

我正在尝试创建一个聊天机器人，该机器人将继续询问有关输入主题的问题，直到用户单击“取消”按钮为止。对编码不熟悉，我不确定如何检查是否单击了取消按钮，但据我所知，一旦单击了按钮，它将返回“ null”。我认为下面的代码很接近，但是每当我取消时都会产生一条错误消息。

代码：

JOptionPane.showMessageDialog(null, "Hi! This is your chatbot. We will now begin the input taking phase");

        String topicOne = JOptionPane.showInputDialog("Please enter topic 1");
        String topicTwo = JOptionPane.showInputDialog("Please enter topic 2");
        String topicThree = JOptionPane.showInputDialog("Please enter topic 3");


        JOptionPane.showMessageDialog(null, "Thank you for the topics, we will now begin the chatting phase");

        String response = "hello";
        boolean questionMark;
        boolean containsTopicOne;
        boolean containsTopicTwo;
        boolean containsTopicThree;

        while (response != null) {
            response = JOptionPane.showInputDialog("Please tell me more about " + topicOne + ", " + topicTwo + ", " + topicThree + "...");
            questionMark = response.indexOf('?') >= 0;
            containsTopicOne = response.indexOf(topicOne) >= 0;
            containsTopicTwo = response.indexOf(topicTwo) >= 0;
            containsTopicThree = response.indexOf(topicThree) >= 0;

            if (questionMark == true) {
                JOptionPane.showMessageDialog(null, "I'll be the one asking the questions!");
                questionMark = false;
                containsTopicOne = false;
                containsTopicTwo = false;
                containsTopicThree = false;
            }
            else if (containsTopicOne == true || containsTopicTwo == true || containsTopicThree == true){
                JOptionPane.showMessageDialog(null, "NIce to know!");
                questionMark = false;
                containsTopicOne = false;
                containsTopicTwo = false;
                containsTopicThree = false;
            }
            else {
                JOptionPane.showMessageDialog(null, "Stay on topic!");
                questionMark = false;
                containsTopicOne = false;
                containsTopicTwo = false;
                containsTopicThree = false;
            }
        }
}

错误消息：线程“主”中的异常java.lang.NullPointerException 在actionPerformed.main（actionPerformed.java:31）

对于简化代码，任何帮助或建议都将非常感谢。

Answer 1

这是一个示例是/否：

if (JOptionPane.showConfirmDialog(null, "Are you sure?", "WARNING",
        JOptionPane.YES_NO_OPTION) == JOptionPane.YES_OPTION) {
    // yes selected
} else {
    // no selected
}

JOptionPane一旦单击取消按钮，如何退出代码

1 个答案: