我正在尝试访问WordSelect类中的变量，然后我尝试在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
}
}
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
}
}
答案 0 :(得分：1)
您可以将变量更改为static variable，因为在这种情况下，我认为wd变量与您的类中的任何对象无关。因此，static variable必须符合您的需求。然后，您只需以Classname.variable的形式使用它。
在WordSelect课程中：
public class WordSelect {
public static String wd = words[choice];
public WordSelect(){
....
....
}
public void Start(int diff){
....
....
}
然后，在GameCalss：
public class Game {
public static void game(){
system.out.println(WordSelect.wd);
}
}
注意： static variable应在任何方法之外定义。
答案 1 :(得分：0)
你能做的最好的事情是为你的班级宣布一个ivar。在这里，我称之为wordSelection。
然后在构造函数方法中，您可以为ivar指定初始值（空）。
此外，您必须添加所谓的“存取方法”才能读取ivar。在这里，我称之为getWordSelection。
在Game课程中，您需要instance课程WordSelection。您可以使用new关键字来完成此操作。请参阅代码以获取示例。
最后，我在代码中的任何位置都没有看到main方法。您需要一个能够运行和测试您的程序。
import static java.lang.System.*;
import java.util.*;
public class WordSelect {
// Add a priate ivar here...
private String wordSelection;
public WordSelect(){
// give the ivar an initial value
this.wordSelection = "";
}
// Add the method to access the ivar...
public String getWordSelection()
{
// this will return your saved word
return wordSelection;
}
public void Start(int diff){
String words[] = new String[26];
switch(diff){
// Your switch code here
// I removed the switch code to keep the answer short
}
int i = words.length;
Random rng = new Random();
int choice = rng.nextInt(words.length); //Varible storing random word
// This is what you have to do
wordSelection = words[choice];
}
}
游戏类：
import static java.lang.System.*;
import java.util.*;
public class Game {
public static void game(){
// This is how you instantiate your WordSelect class
WordSelect wordSelect = new WordSelect();
// call the "Start" method
wordSelect.Start(30);
// This is how you can access the ivar
out.println(wordSelect.getWordSelection());
}
}
希望这有帮助！
答案 2 :(得分：0)
你必须要做一些事情。首先，您需要创建一个变量来保存WordSelect类中的String，如下所示：
String wd;
接下来你需要一个返回字符串的return方法：
public String returnWord()
{
return wd;
}
现在我们需要在你的主要做一些事情。首先我们需要创建一个WordSelect对象，然后我们需要调用Start方法，然后我们需要调用returnWord方法并将其分配给一个字符串。
WordSelect words = new WordSelect();
words.Start(1);
String str = words.returnWord();
System.out.println(str);
答案 3 :(得分：0)
你可以通过以下方式实现这一目标：
import static java.lang.System.*;
import java.util.*;
public class WordSelect {
public WordSelect(){
}
private String wd = "";
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
this.wd = words[choice];
}
//// setter and getter of wd;
public void setWd(String wd) {
this.wd = wd;
}
public String setWd() {
return this.wd;
}
}
Game.java
import static java.lang.System.*;
import java.util.*;
public class Game {
public static void game(){
WordSelect ws = new WordSelect();
out.println(ws.getWd());
}
}
答案 4 :(得分：0)
有几种方法可以解决这个问题。
1您可以更改start方法以返回String。
public String start(int diff){
...
String wd = words[choice];
return wd;
}
然后
WordSelect ws = new WordSelect();
out.println(ws.start());
注意我将Start方法更改为start，方法应该从小写开始。
2您可以将其保存为WordSelect
中的类属性public class WordSelect {
private String word;
...
public String start(int diff){
...
String wd = words[choice];
word = wd;
}
...
public String getWord(){
return word;
}
}
然后
WordSelect ws = new WordSelect();
ws.start();
out.println(ws.getWord());
3您也可以尝试将属性保存为公共属性而不是getter。不建议这样做，因为你正在失去OO封装的最佳功能之一。
4您也可以将其保存为所提到的静态变量，但这些应保持在最低限度。静态变量有它们的位置，例如常量，但它们并不是真正的OO方式。请记住，静态变量将应用于同一类的所有对象。 OO的主要好处之一是您可以拥有来自同一类的不同对象，每个对象具有不同的“状态”。
我想我会设计这些类有点不同。为什么每次想要获得随机字时都要初始化数组？在其他地方做这种事情可能会更好，可能在构造函数中，然后使用单个方法来获取随机单词。将数组保持为该类的私有，以便封装它。这样，您可以在将来轻松更改它以使用ArrayList或其他任何内容。