我之前曾使用过几种方法来接受用户输入并将其以某一数据类型返回给调用该方法的方法。我在之前的项目中使用了这些方法或它们的变体。
我采用了我用于字符串的方法，选择给定的第一个字符并返回它，以便在菜单中使用。每次启动应用程序时，主菜单都会出现并等待用户输入。接收到此输入后，程序将持续循环直到停止。以下是我捕获字符的方法：
代码由于try/catch块而循环，因为scan.nextLine()从不等待下一个输入。如果没有它，异常通常与找不到新行有关。我尝试了while(scan.hasNextLine())，似乎对其他人有效；但是，一旦输入时间到达，它就永远无法跳出循环。我也不认为我会遇到每个人都遇到的nextInt()问题。我将在下面发布整个类的代码：
我采用了我用于字符串的方法，选择给定的第一个字符并返回它，以便在菜单中使用。每次启动应用程序时，主菜单都会出现并等待用户输入。接收到此输入后，程序将持续循环直到停止。以下是我捕获字符的方法：
private char getUserChar(String prompt) {
try {
Scanner scan = new Scanner(System.in);
System.out.print(prompt);
String tempString = "";
tempString = scan.nextLine();
scan.close();
char userChar = tempString.charAt(0);
return userChar;
} catch(Exception ex) {
System.out.println(ex.getMessage());
}
return 0;
}
代码由于try/catch块而循环，因为scan.nextLine()从不等待下一个输入。如果没有它，异常通常与找不到新行有关。我尝试了while(scan.hasNextLine())，似乎对其他人有效；但是，一旦输入时间到达，它就永远无法跳出循环。我也不认为我会遇到每个人都遇到的nextInt()问题。我将在下面发布整个类的代码：
import java.util.Scanner;
import controller.Controller;
public class TUI {
private Controller controller;
public TUI() {
Controller controller = new Controller();
this.controller = controller;
}
public void run() {
boolean wantToQuit = false;
char userInput = 0;
System.out.println("Welcome to the Mart.");
do{
userInput = mainMenu();
if(isUserInputValid(userInput))
switch(userInput){
case 'a': addItem();
break;
case 'r': controller.removeItem();
break;
case 'i': controller.printInventory();
break;
case 'p': controller.customerPurchase();
break;
case 'w': controller.weeklyStock();
break;
case 'c': wantToQuit = true;
break;
}
else System.out.println("\nMainMenu");
} while(!(wantToQuit));
System.out.println("WolfMart is now closed. Thank you and good-bye.");
}
private boolean isUserInputValid(char userInput) {
char[] testSet = {'a', 'r', 'i', 'p', 'c', 'w'};
for(char currentChar : testSet) {
if(currentChar == userInput)
return true;
}
return false;
}
private char mainMenu() {
System.out.println();
controller.printInventory();
String mainMenuSelection = "What would you like to do: (a)dd item, (r)emove item, print (i)nventory, " +
"(p)urchase by customer, (c)lose store?\r\n";
char mainMenuInput = getUserChar(mainMenuSelection);
return mainMenuInput;
}
private char getUserChar(String prompt) {
try {
Scanner scan = new Scanner(System.in);
System.out.print(prompt);
String tempString = "";
tempString = scan.nextLine();
scan.close();
char userChar = tempString.charAt(0);
return userChar;
} catch(Exception ex) {
System.out.println(ex.getMessage());
}
return 0;
}
private int getUserInt(String prompt) {
Scanner scan = new Scanner(System.in);
int userInt = -1;
try {
System.out.print(prompt);
String input = scan.nextLine();
userInt = Integer.parseInt(input);
}
catch(NumberFormatException nfe) {
System.out.println("I did not recognize your command, please try again.");
}
scan.close();
return userInt;
}
private String getUserString(String prompt) {
Scanner scan = new Scanner(System.in);
String userString = null;
try{
System.out.print(prompt);
userString = scan.nextLine();
} catch(Exception ex)
{
System.out.println("I did not recognize your command, please try again.");
}
scan.close();
return userString;
}
private double getUserDouble(String prompt) {
Scanner scan = new Scanner(System.in);
double userDouble = -1.0;
try {
System.out.print(prompt);
String input = scan.nextLine();
userDouble = Double.parseDouble(input);
}
catch(NumberFormatException nfe) {
System.out.println("I did not recognize your command, please try again.");
}
scan.close();
return userDouble;
}
private void addItem() {
String itemName = "";
double price;
int quantity;
String namePrompt = "Enter the name of the item being added to the inventory: ";
String pricePrompt = "Enter the cost of " + itemName + ": ";
String quantityPrompt = "Enter the quantity of " + itemName + ": ";
itemName = getUserString(namePrompt);
price = getUserDouble(pricePrompt);
quantity = getUserInt(quantityPrompt);
controller.addItem(itemName, quantity, price);
}
}