java - 如何从不同的类访问变量

Question

我正在尝试访问 WordSelect 类中的变量，然后尝试在 Game 类中使用它。代码如下:WordSelect 类:

import static java.lang.System.*;
import java.util.*;

public class WordSelect {

    public WordSelect(){

    }

    public void Start(int diff){
        String words[] = new String[26];
        switch(diff){
        case 1:
            words[0] = "cat";
            words[1] = "dog";
            words[2] = "book";          
            words[3] = "breakfeast";          
            words[4] = "telephone";          
            words[5] = "mixture";          
            words[6] = "music";          
            words[7] = "animal";          
            words[8] = "school";          
            words[9] = "plant";          
            words[10] = "pen";          
            words[11] = "pencil";          
            words[12] = "paper";          
            words[13] = "note";          
            words[14] = "fog";          
            words[15] = "smoke";        
            words[16] = "bake";          
            words[17] = "alone";          
            words[18] = "drive";          
            words[19] = "town";          
            words[20] = "city";          
            words[21] = "sunny";          
            words[22] = "shine";          
            words[23] = "polish";          
            words[24] = "cap";          
            words[25] = "hat";
            break;

        case 2:
            words[0] = "president";
            words[1] = "exclamation";          
            words[2] = "statement";          
            words[3] = "television";          
            words[4] = "physics";          
            words[5] = "algebra";          
            words[6] = "geometry";          
            words[7] = "difficult";          
            words[8] = "extreme";          
            words[9] = "procedure";          
            words[10] = "ship";          
            words[11] = "soldier";          
            words[12] = "lunch";          
            words[13] = "hockey";          
            words[14] = "tennis";          
            words[15] = "soccer";          
            words[16] = "football";          
            words[17] = "basketball";          
            words[18] = "bias";          
            words[19] = "magazine";          
            words[20] = "computer";          
            words[21] = "internet";          
            words[22] = "allegedly";          
            words[23] = "system";          
            words[24] = "unison";          
            words[25] = "excited";         
            break;

        case 3:
            words[0] = "amalgamation";          
            words[1] = "proclomation";          
            words[2] = "establishment";          
            words[3] = "rehabilitation";          
            words[4] = "rhinoceros";          
            words[5] = "velociraptor";         
            words[6] = "declaration";         
            words[7] = "announcement";          
            words[8] = "binomial";          
            words[9] = "polynomial";          
            words[10] = "congregation";          
            words[11] = "obligation";          
            words[12] = "structure";          
            words[13] = "description";          
            words[14] = "perscription";          
            words[15] = "subscribe";          
            words[16] = "address";          
            words[17] = "township";          
            words[18] = "mischievous";          
            words[19] = "bewildered";          
            words[20] = "accusation";          
            words[21] = "designation";          
            words[22] = "disgusting";          
            words[23] = "prolonged";          
            words[24] = "restoration";          
            words[25] = "regeneration";          
        }

        int i = words.length;

        Random rng = new Random();
        int choice = rng.nextInt(words.length); //Varible storing random word
        String wd = words[choice];
        // Not sure what to put here to make wd available in the other class
     }
}

以及游戏类:

import static java.lang.System.*;
import java.util.*;

public class Game {

    public static void game(){
        out.println(wd); //Trying to print out the wd variable from WordSelect

    }
}

Answer 1

您可以将变量更改为静态变量，因为在您的情况下，我认为wd变量与您的类中的任何对象都不相关。因此，静态变量必须满足您的需要。然后，您只需以Classname.variable的形式使用它即可。

在 WordSelect 类中:

public class WordSelect {
public static String wd = words[choice];
public WordSelect(){
    ....
    ....
}

public void Start(int diff){
    ....
    ....
}

然后，在 GameCalss 中:

public class Game {

public static void game(){
    system.out.println(WordSelect.wd);  

}
}

注意:静态变量应该在任何方法之外定义。