Question

我制作一个测验程序，调用两个.txt文件（一次一个）来获取问题和答案。这两个文件有不同数量的问题和答案。它按顺序通过它们，在你得到最后一个问题的答案并点击获取问题按钮后，它会给出索引超出范围的错误。我试图找出在显示最后一个问题后让jbuttonQ被禁用的最佳方法。我想我错过了一个for循环或尝试捕获某个地方。问题和答案是单独的ArrayList

这里是jbuttonQ动作执行的代码：

 statusMessageLabel.setText("");
 jtxtA.setText("");
 jtxtQ.setText(q.getQuestion());
 jtxtCurrQ.setText(String.valueOf(q.getQNumber()));
 jbtnA.setEnabled(true);
 jbtnA.requestFocusInWindow();
 jbtnQ.setEnabled(false);

这里是jbuttonA动作执行的代码：

statusMessageLabel.setText("");
    jtxtA.setText(q.getAnswer());
    jbtnQ.setEnabled(true);
    jbtnQ.requestFocusInWindow();
    jbtnA.setEnabled(false);

这里是jbtnMenu代码：

statusMessageLabel.setText("");
    jtxtQ.setText("");
    jtxtA.setText("");
    jtxtCurrQ.setText("");
    jtxtTotQ.setText("");
    JFileChooser f = new JFileChooser(".");
    String path = "";
    f.setDialogTitle("Select quiz file.");
    FileNameExtensionFilter filter = new FileNameExtensionFilter("Text file (*.txt)","txt");
    f.setFileFilter(filter);
    JDialog dg = new JDialog();
    int rval = f.showOpenDialog(dg);
    if(rval == JFileChooser.CANCEL_OPTION){
        statusMessageLabel.setText("Open canceled.");
        jtxtFile.setText("");
    }else{
        path = f.getSelectedFile().getAbsolutePath();
        jtxtFile.setText(path);
        q = new Quiz(path); //instantiation call
        if(q.getErrorMsg().isEmpty()){
            statusMessageLabel.setText(q.getActionMsg());
            jtxtTotQ.setText(String.valueOf(q.getQCount()));
            jbtnQ.setEnabled(true);
            jbtnQ.requestFocusInWindow();
        }else{
            statusMessageLabel.setText(q.getErrorMsg());
        }
    }
}

这是Quiz.java类：

public class Quiz {
private String filename;
private String errmsg, actmsg;
private ArrayList<String> questions;
private ArrayList<String> answers;
private int qCount, qNumber;
private boolean quizover;

public Quiz(String path){
    this.errmsg = "";
    this.actmsg = "";
    questions = new ArrayList<>();
    answers = new ArrayList<>();

    try{
        BufferedReader in = new BufferedReader(new FileReader(path));
        String s = in.readLine();
        while (s != null){
            questions.add(s);
            answers.add(in.readLine());
            qCount++;
            s = in.readLine();
        }
        in.close();

    }catch(IOException e){
        this.errmsg = "Unable to open file " + path;
    }
    if (qCount > 0){
        this.actmsg = "Quiz file has " + qCount + " questions.";
        qNumber = 1;
        quizover = false;
    }else if(qCount <= 0){
        this.actmsg = "No questions in file: " + path;
        qNumber = 0;
        quizover = true;
     }
}//end of constructor
public String getErrorMsg(){
    return this.errmsg;
}
public String getActionMsg(){
    return this.actmsg;
}
public int getQCount(){
    return this.qCount;
}
public int getQNumber(){
    return this.qNumber;
}
public String getQuestion(){

    if(this.qCount == 0){
        this.errmsg = "Question requested from empty quiz.";
        return this.errmsg;
    }


    return this.questions.get(this.qNumber - 1);
}
public String getAnswer(){
    if(this.qCount == 0){
        this.errmsg = "Answer requested from empty quiz.";
        return this.errmsg;
    }
    String a = this.answers.get(this.qNumber - 1);
    qNumber ++;
    return a;
}

}

任何帮助将不胜感激。感谢。

Answer 1

我知道你还没有分享完整的代码;所以，我此时对你的代码的理解是有限的。

但是，最大的问题是你正在使用this.qCount检查“最后一个问题”，但你得到的是this.qNumber;你还需要减少qNumber。试试这样的事情：

public String getQuestion(){

    if (this.qNumber > 0) {
        return this.questions.get(this.qNumber - 1);
    }
    else {
        this.errmsg = "Question requested from empty quiz.";
        return this.errmsg;
    }
}

public String getAnswer(){

    if (this.qNumber > 0) {
        String a = this.answers.get(this.qNumber - 1);
        qNumber--;
        return a;
    }
    else {
        this.errmsg = "Answer requested from empty quiz.";
        return this.errmsg;
    }
}

Answer 2

我想通了，我改变了jbtnA代码：

 statusMessageLabel.setText("");
    if(String.valueOf(q.getQNumber()).equals(String.valueOf(q.getQCount()))){
        statusMessageLabel.setText("End of questions in file.");
        jbtnQ.setEnabled(false);
    }else{
    jtxtA.setText(q.getAnswer());
    jbtnQ.setEnabled(true);
    jbtnQ.requestFocusInWindow();
    jbtnA.setEnabled(false);
    }

在测验计划中指数超出界限

2 个答案: