java - 我的扫描仪会跳过下一个 double 型和下一个整数吗？

Question

这个问题已经有答案了:

Scanner is skipping nextLine() after using next() or nextFoo()? (25 个回答)

已关闭 9 年前。

每当我运行扫描仪时，它都会跳过重量后的高度(双)循环。它还会在年龄之后跳过 level(int) 循环。

这是我的扫描仪类。

导入java.util.Scanner;

 public class HowHealthy
 {
   public static void main(String[] args)
    {
   String aGender = "";

   //New healthy objec tis created
   Healthy person = new Healthy();

   //Scanner object is created
   Scanner in = new Scanner(System.in);

   String name = "";
   while(!person.setName(name))
   {
       System.out.print("Person's name: ");
       name = in.nextLine();
       if(!person.setName(name))
       {
           System.out.println("Invalid name - must be at least one character!");
       }
   }

   char gender = '\0';
   while(!person.setGender(gender))
   {
       System.out.print(name + ", are you male of female (M/F): ");
       gender = in.nextLine().toUpperCase().charAt(0);
       if(!person.setGender(gender))
       {
           System.out.println("Invalid gender - must be M or F (upper or lower case)":
       }
    }

   double weight = 0;
   while(!person.setWeight(weight))
   {
       System.out.print(name + "'s weight (pounds): ");
       weight = in.nextDouble();
       in.nextLine();
       if(!person.setWeight(weight))
       {
           System.out.println("Invalid weight - must be at least 100 pounds!");
       }
    }

   double height = 0;
   while(!person.setHeight(height))
   {
       System.out.print(name + "'s height (inches): ");
       height = in.nextDouble();
       if(!person.setHeight(height))
       {
           System.out.println("Invalid height - must be 60..84, inclusively!");
       }
   }

   int age = 0;
   while(!person.setAge(age))
   {
       System.out.print(name + "'s age (years): ");
       age = in.nextInt();
       in.nextLine();
       if(!person.setAge(age))
       {
           System.out.println("Invalid age - must be at least 18!");
        }
   }

   System.out.println();

   System.out.println("Activity Level: Use these categories:");
   System.out.println("\t1 - Sedentary (little or no exercise, desk job)");
   System.out.println("\t2 - Lightly active (little exercise / sports 3-5 days/wk");
   System.out.println("\t3 - Moderately active(moderate exercise / sports 3-5
   System.out.println("\t4 - Very active (hard exercise / sports 6 -7 day/wk)");
   System.out.println("\t5 - Extra active (hard daily exercise / sports \n\t physica2X)

    int level = 0;
   while(!person.setLevel(level))
   {
       System.out.print("How active are you? ");
       level = in.nextInt();
       if(!person.setLevel(level))
       {
           System.out.println("Invalid acitvity level - must be 1..5, inclusively!");
        }
   }


   System.out.println();

   //Creates a new Healthy object and prints values based on user's input

   System.out.println(person.getName()+ "'s information");
   System.out.printf("Weight: %.1f %s \n", person.getWeight(), "pounds");
   System.out.printf("Height: %.1f %s \n", person.getHeight(), "inches");
   System.out.println("Age: " + person.getAge() + " years");

   if (gender == 'M')
   {
      aGender = "male";
   }      
   else
   {
      aGender = "female";
   }
   System.out.println("These are for a " + aGender);
   System.out.println();

   //Calculates the person's BMR, BMI and TDEE based on user input
   System.out.printf("BMR is %.2f \n", person.calcBMR());
   System.out.printf("BMI is %.2f \n", person.calcBMI());
   System.out.printf("TDEE is %.2f \n", person.calcTDEE());

   //Determines person's weight status based on BMI calculated
   double BMI = person.calcBMI();

   //Displays person's weight status
   System.out.println("Your BMI classifies you as " + person.calcWeightStatus());  

    }
   }

这是我的扫描仪类(class)。

Answer 1

在这两种情况下，执行 in.nextInt() 后都会丢失 in.nextLine()。如果所有其他代码行都使用 in.nextDouble() 和 in.nextLine() 之类的东西工作，我的猜测是这就是缺少的内容。