我遇到的问题是，我创建了一系列字符串，其中包含带有项目名称的数组和用于价格的双精度数组。适合三组条件：花朵、颜色、尺寸。我还为菜单创建了一个切换方法，现在这就是我陷入困境的地方。当我调用扫描仪获取有关花朵、颜色和尺寸的信息时，它不起作用。菜单显示了，但如果我去订购列出的鲜花，它们就不会显示。有人建议我不要使用扫描仪，还有其他方法可以做到这一点吗？如果可以的话，该怎么做？
import java.util.Scanner;
public class MenuTest2B {
// create flowers + price arrays
public static final String[] FLOWERS = {"Roses", "Lilys", "Carnations", "Daffodils", "Gerberas", "Chrysanthemums", "Assorted"};
public static final double[] FLOWER_PRICES = {1.2, 1.3, 1.0, 1.0, 1.1, 1.1, 0.8};
// create colours + price arrays
public static final String[] COLOURS = {"White", "Red", "Pink", "Yellow", "Blue", "Mixed"};
public static final double[] COLOUR_PRICES = {1.3, 1.2, 1.1, 1.1, 1.2, 1.0};
// create size + price arrays
public static final String[] SIZES = {"Small", "Medium", "Large"};
public static final double[] SIZE_PRICES = {5.5, 7.5, 9.5};
public static void main(String[] args) {
try (Scanner scanner = new Scanner(System.in)) {
int Choice;
do
{
displayMenu();
Choice = getUserChoice(scanner);
switch (Choice) {
case 1:
// use scanner to display menu options for flowers col ours and size
orderDetailsAndPriceCalculation(scanner);
break;
case 2:
summaryStatistics();
break;
case 3:
System.out.println("You are exiting the program... Goodbye");
break;
default:
System.out.println("Invalid input. Please select a valid option.");
}
} while (Choice != 3);
}
}
private static void displayMenu() {
System.out.println("Main Menu");
System.out.println("1. Order a bouquet and get the price.");
System.out.println("2. Display statistics");
System.out.println("3. Exit");
}
public static int getUserChoice(Scanner scanner) {
int choice = -1;
try {
choice = Integer.parseInt(scanner.nextLine());
} catch (NumberFormatException e) {
// Invalid input, choice will remain -1
}
return choice;
}
public static void orderDetailsAndPriceCalculation(Scanner scanner) {
int i;
// adds values for chosen ammounts for orders and puts them into the scanner
int flowerChoice = getFlowerChoice(scanner);
if (flowerChoice == -1) return;
int colourChoice = getColourChoice(scanner);
if (colourChoice == -1) return;
int sizeChoice = getSizeChoice(scanner);
if (sizeChoice == -1) return;
// calculates the input order details (Flower+Colour)*Size
double totalPrice = (FLOWER_PRICES[flowerChoice] + COLOUR_PRICES[colourChoice]) * SIZE_PRICES[sizeChoice];
// PRINT TOTAL AMOUNT
// AND DETAILS OF BOUQUET
System.out.println("Bouquet: " + SIZES[sizeChoice] + " " + COLOURS[colourChoice] + " " + FLOWERS[flowerChoice] + ".");
System.out.println("Bouquet Price: £" + totalPrice);
}
public static void summaryStatistics() {
System.out.println("Summary statistics provided");
}
}
我建议对您的代码进行一些更改，首先在main中， 在其中，我们创建一个 MenuTest2B 对象，并用它来调用 init() 这将执行程序，这样，我们就避免了所有那些丑陋的static（和不必要的）。
我还修改了属性FLOWERS，FLOWER_PRICES和COLOURS，在其中添加短语“选择你的”及其自己的描述，这将帮助我创建相应的菜单。
创建 menu 属性，目的相同。
为了理解这些修改，可以使用 displayMenu() 方法，该方法接收相应的数组并打印菜单。
我删除了 Scanner 声明并将其作为属性，以便正确关闭它，并添加了 getInput() 方法，该方法返回已处理的用户输入。
在 exec 中，将 displayMenu(); 更改为 displayMenu(menu );，因为它现在需要参数。
在 orderDetailsAndPriceCalculation() 中添加对 displayMenu( FLOWERS )、displayMenu( COLORS ) 和 displayMenu( SIZES ) 的调用，这些调用是缺失的。
仍然需要实施summaryStatistics，我把它留给你了。
当然，您会注意到，在价格数组中，我添加了第一个值“0”，这是为了使所选值与用户的选择相匹配（在FLOWERS，FLOWER_PRICES和COLOURS中添加，具有相同的效果）。
public class MenuTest2B {
public final String[] FLOWERS = { "Choose your flower:", "Roses", "Lilys", "Carnations", "Daffodils", "Gerberas", "Chrysanthemums", "Assorted" };
public final double[] FLOWER_PRICES = { 0, 1.2, 1.3, 1.0, 1.0, 1.1, 1.1, 0.8 };
// create colours + price arrays
public final String[] COLOURS = { "Choose your colour:", "White", "Red", "Pink", "Yellow", "Blue", "Mixed" };
public final double[] COLOUR_PRICES = { 0, 1.3, 1.2, 1.1, 1.1, 1.2, 1.0 };
// create size + price arrays
public final String[] SIZES = { "Choose your size:", "Small", "Medium", "Large" };
public final double[] SIZE_PRICES = { 0, 5.5, 7.5, 9.5 };
private Scanner scanner;
public final String[] menu = { "Main Menu", "1. Order a bouquet and get the price.", "2. Display statistics", "3. Exit" };
private void displayMenu( String obj[] ) {
for( int i = 0; i < obj.length; i ++ ) {
if( i == 0 ) {
System.out.println( obj[ i ] );
}
else {
System.out.println( i + ". " + obj[ i ] );
}
}
}
public void init() {
scanner = new Scanner( System.in );
int choice;
do {
displayMenu( menu );
choice = getInput();
switch( choice ) {
case 1:
// use scanner to display menu options for flowers col ours and size
orderDetailsAndPriceCalculation();
break;
case 2:
summaryStatistics();
break;
case 3:
System.out.println( "You are exiting the program... Goodbye" );
scanner.close();
break;
default:
System.out.println( "Invalid input. Please select a valid option." );
}
}
while( choice != 3 );
}
public void orderDetailsAndPriceCalculation() {
int i;
// adds values for chosen ammounts for orders and puts them into the scanner
System.out.println( "" );
displayMenu( FLOWERS );
int flowerChoice = getInput();
if( flowerChoice == -1 ) {
return;
}
displayMenu( COLOURS );
int colourChoice = getInput();
if( colourChoice == -1 ) {
return;
}
displayMenu( SIZES );
int sizeChoice = getInput();
if( sizeChoice == -1 ) {
return;
}
// calculates the input order details (Flower+Colour)*Size
double totalPrice = ( FLOWER_PRICES[ flowerChoice ]
+ COLOUR_PRICES[ colourChoice ] )
* SIZE_PRICES[ sizeChoice ];
// PRINT TOTAL AMOUNT
// AND DETAILS OF BOUQUET
System.out.println( "Bouquet: " + SIZES[ sizeChoice ] + " " + COLOURS[ colourChoice ] + " " + FLOWERS[ flowerChoice ] + "." );
System.out.println( "Bouquet Price: £" + totalPrice );
}
public void summaryStatistics() {
System.out.println( "Summary statistics provided" );
}
int getInput() {
try {
return scanner.nextInt();
}
catch( Exception e ) {
return -1;
}
}
public static void main( String[] args ) {
MenuTest2B mt2 = new MenuTest2B();
mt2.exec();
}
}