java - 扫描仪不会停止获取输入

Question

好吧，非常菜鸟的问题。我正在制作一个允许用户设计调查的 CLI 应用程序。首先他们输入问题，然后输入选项的数量和选项。我正在使用扫描仪获取输入，出于某种原因，它允许用户输入大部分内容，但不能输入问题的文本。下面的代码片段。

String title = "";
Question[] questions;
int noOfQuestions = 0;
int[] noOfChoices;
Scanner entry = new Scanner(System.in);
System.out.println("Please enter the title of the survey: ");
title = entry.nextLine();
System.out.println("Please enter the number of questions: ");
noOfQuestions = entry.nextInt();
noOfChoices = new int[noOfQuestions];
questions = new Question[noOfQuestions];
for (int i = 0; i < noOfQuestions; i++) {
    questions[i] = new Question();
}
for (int i = 0; i < noOfQuestions; i++) {

    System.out.println("Please enter the text of question " + (i + 1) + ": ");
    questions[i].questionContent = entry.nextLine();
    System.out.println("Please enter the number of choices for question " + (i + 1) + ": ");
    questions[i].choices = new String[entry.nextInt()];
    for (int j = 0; j < questions[i].choices.length; j++) {
        System.out.println("Please enter choice " + (j + 1) + " for question " + (i + 1) + ": ");
        questions[i].choices[j] = entry.nextLine(); 

    }
}

谢谢:)

Answer 1

我问你是否从扫描仪读取 noOfQuestions 的原因是因为 Scanner.nextInt() 不使用分隔符(例如新行)。

这意味着下次调用 nextLine() 时，您只会从之前的 readInt() 中得到一个空字符串。

75\nQuestion 1: What is the square route of pie?
^ position before nextInt()

75\nQuestion 1: What is the square route of pie?
  ^ position after nextInt()

75\nQuestion 1: What is the square route of pie?
    ^ position after nextLine()

我的建议是按行阅读，始终使用 nextLine()，然后使用 Integer.parseInt() 进行解析。

如果那是您选择的路线，则根本不需要扫描仪；你可以只接受一个 BufferedReader。