java - 输入对话框显示随机 "-1"

Question

一切运行完美，但String am1 = (String)JOptionPane.showInputDialog显示随机默认值“-1”。

private void am1ActionPerformed(java.awt.event.ActionEvent evt) {     

getinfo();//Set the random question and answer
    am1.setEnabled(false);
Object[] options = {"Answer", "Cancel"};
int n = JOptionPane.showOptionDialog(null,
        JeopardyGUI.question1_1,//Reference the question set
        "",
        JOptionPane.YES_NO_OPTION,
        JOptionPane.PLAIN_MESSAGE,
        null,     //do not use a custom Icon
        options,  //the titles of buttons
        options[0]); //default button title

    if(n == JOptionPane.YES_OPTION){
       String am1 = (String)JOptionPane.showInputDialog("",JOptionPane.PLAIN_MESSAGE);

       if(am1.equalsIgnoreCase(JeopardyGUI.answer1_1)){
           Jscore += 100;
           JOptionPane.showMessageDialog(null, JeopardyGUI.answer1_1 );
       }
       else if(!am1.equalsIgnoreCase(JeopardyGUI.answer1_1)){
           Jscore += -100;
           JOptionPane.showMessageDialog(null, JeopardyGUI.answer1_1 );
       }
 //           else
 //               am1.setEnabled(true);

    }
    if(n == JOptionPane.NO_OPTION){
        //am1.setVisible(false);
        am1.setEnabled(true);
    }
}                                   

Answer 1

您正在使用:

public static String showInputDialog(Object message, Object initialSelectionValue)

在这种情况下，JOptionPane.PLAIN_MESSAGE 是您的初始选择值。我猜它是一个等于-1的int。你真正想要的可能是:

JOptionPane.showInputDialog("Actual message", "");

另外，请小心:

String am1 = ...

正在隐藏 am1 类成员，它看起来是某个组件。

我还可以建议将处理逻辑重写为:

if(am1 != null && am1.equalsIgnoreCase(JeopardyGUI.answer1_1)){
    Jscore += 100;
else Jscore += -100;
JOptionPane.showMessageDialog(null, JeopardyGUI.answer1_1 );