如何在 bukkit 中创建计算器？

Question

我只是在学习 bukkit，我想像使用所有新的编程语言（我知道基本的 Java）一样制作一个计算器，但我似乎无法找到一种方法来添加某人输入的 args 而我找不到bukkit 的教程。任何人都可以帮我解析这些数字，因此如果您尝试添加不是双精度的东西，它会给出不同的错误消息。我尝试添加一个 switch 语句来执行此操作，但没有奏效。

这是我目前得到的......

public boolean onCommand(CommandSender sender, Command cmd, String commandLabel, String[] args){
    @SuppressWarnings("unused")
    Player player = (Player) sender;
    if(commandLabel.equalsIgnoreCase("calc")){
        if(args.length == 1){
            String n1 = args[0];
            if (true){
                if (args[0].equalsIgnoreCase("+") || args[0].equalsIgnoreCase("-")){
                    String n2 = args[1];
                    if (args[0].equalsIgnoreCase("+")){
                        double answer = Double.parseDouble(n1) + Double.parseDouble(n2);
                        sender.sendMessage("The answer is " + answer);
                    }

                    }else{
                        sender.sendMessage("Please use + or -");
                }
            }
        }else{
            sender.sendMessage(ChatColor.RED + "Incorrect Syntax");
        }
    }
    return false;
}

}

Answer 1

你可以这样做：

public boolean onCommand(CommandSender sender, Command cmd, String commandLabel, String[] args){
  if(cmd.getName().equalsIgnoreCase("add")){//if the comand is /add
  if(args.length == 2){// if there are two arguments
     try{
       long n1 = Long.parseLong(args[0]);//get the first number
       long n2 = Long.parseLong(args[1]);//get the second number
       long result = n1 + n2;//add the two numbers together
       sender.sendMessage(n1 + " + " + n2 + " equals " + result);//tell the sender the result

     }
     catch(Exception e){
       //the user did not enter numbers
     }
   }
   else{
     sender.sendMessage("usage: /add num1 num2");
   }
}
return true;
}
return false;
}

然后你可以做/add <number 1> <number 2>，它会为你把这些数字加在一起

Answer 2

我编辑了你的代码，现在它可以工作了！

public boolean onCommand(CommandSender s, Command cmd, String label, String[] args) {
    if (cmd.getName().equalsIgnoreCase("calc")) { //if the command is /calc
        if (args.length == 3) { // if the command structure is something like this /calc <number> <operator> <number>
            if (args[1].equalsIgnoreCase("+")) { // if the operator is +
                double number1 = 0;
                double number2 = 0;
                double result = 0;
                try { // see if the first and second numbers are a double
                    number1 = Double.parseDouble(args[0]);
                    number2 = Double.parseDouble(args[2]);
                } catch (Exception e) { // if the two arguments aren't numbers
                    s.sendMessage(ChatColor.RED + "The argument " + ChatColor.DARK_RED + args[0] + ChatColor.RED
                            + " or the argument " + ChatColor.DARK_RED + args[2] + ChatColor.RED
                            + " is not a number !");
                    return false; // the code stops here
                }
                result = number1 + number2; // doing the adition
                s.sendMessage(ChatColor.GREEN + "" + number1 + " + " + number2 + " = " + result); // send message to the player with the resut
            } else if (args[1].equalsIgnoreCase("*")) { //same as adition
                double number1 = 0;
                double number2 = 0;
                double result = 0;
                try {
                    number1 = Double.parseDouble(args[0]);
                    number2 = Double.parseDouble(args[2]);
                } catch (Exception e) {
                    s.sendMessage(ChatColor.RED + "The argument " + ChatColor.DARK_RED + args[0] + ChatColor.RED
                            + " or the argument " + ChatColor.DARK_RED + args[2] + ChatColor.RED
                            + " is not a number !");
                    return false;
                }
                result = number1 * number2;
                s.sendMessage(ChatColor.GREEN + "" + number1 + " * " + number2 + " = " + result);
            } else if (args[1].equalsIgnoreCase("/") || args[1].equalsIgnoreCase(":")) { //same as adition
                double number1 = 0;
                double number2 = 0;
                double result = 0;
                try {
                    number1 = Double.parseDouble(args[0]);
                    number2 = Double.parseDouble(args[2]);
                } catch (Exception e) {
                    s.sendMessage(ChatColor.RED + "The argument " + ChatColor.DARK_RED + args[0] + ChatColor.RED
                            + " or the argument " + ChatColor.DARK_RED + args[2] + ChatColor.RED
                            + " is not a number !");
                    return false;
                }
                result = number1 / number2;
                s.sendMessage(ChatColor.GREEN + "" + number1 + args[1] + number2 + " = " + result);
            } else if (args[1].equalsIgnoreCase("-")) { //same as adition
                double number1 = 0;
                double number2 = 0;
                double result = 0;
                try {
                    number1 = Double.parseDouble(args[0]);
                    number2 = Double.parseDouble(args[2]);
                } catch (Exception e) {
                    s.sendMessage(ChatColor.RED + "The argument " + ChatColor.DARK_RED + args[0] + ChatColor.RED
                            + " or the argument " + ChatColor.DARK_RED + args[2] + ChatColor.RED
                            + " is not a number !");
                    return false;
                }
                result = number1 - number2;
                s.sendMessage(ChatColor.GREEN + "" + number1 + " - " + number2 + " = " + result);
            } else {
                s.sendMessage(ChatColor.RED + "Operator not recognized !");
                s.sendMessage(ChatColor.RED + "Please use " + ChatColor.WHITE + "/calc number + number"
                        + ChatColor.RED + " OR " + ChatColor.WHITE + "/calc number - number" + ChatColor.RED
                        + " OR " + ChatColor.WHITE + "/calc number * number" + ChatColor.RED + " OR "
                        + ChatColor.WHITE + "/calc number : number" + ChatColor.WHITE + " to get a result !");
            }
        } else {
            s.sendMessage(ChatColor.RED + "Usage - /calc number operator number ");
        }
    }
    return false;
}