Hi,
I'm trying to build a simple vocab-quiz. It's working fine so far, except for one thing and I can't figure out what the problem might be.
I have a class 'WordList' that stores my words(vocabs) in a HashMap, each vocab having an English meaning value and a German meaning value:
Then there is the class 'AufgabenVerteiler'. It is supposed to draw 4 random numbers without repeat and take those 4 numbers to fetch 4 words from the vocab-list. They are put to wordfields to open up a choice for the player. One of those 4 is then again chosen to be the word in question, so the 2nd-language-value of this word is put to the taskfield, which presents the question. That's how it looks in code:
When I put an object of this class to the Greenfoot-Gaming Area and click on it, it does everything I want it to do. No problems, everything is fine. But I want another class to call the drawWords()-method when clicked on it. There is the OK-class, which is going to check whether the player's choice was right or wrong. And if it is right it shall go and fetch a new set of words. The checkIt()-method isn't coded yet, I first wanted to call the drawWords()-method from the OK-class to see if it works, .... but it doesn't, it just says NPE in AufgabenVerteiler where it should put the random chosen words to the wordfields. And after 2 hours of fiddling around I still have no real idea what's wrong. Maybe someone could point it out to me.
The OK-class:
import greenfoot.*;
import java.util.HashMap;
public class WordList extends Actor
{
HashMap<Integer, Vocab> en_wortliste = new HashMap<Integer, Vocab>();
{
en_wortliste.put(1, new Vocab("hello", "hallo"));
en_wortliste.put(2, new Vocab("friend", "der Freund"));
en_wortliste.put(3, new Vocab("world", "die Welt"));
en_wortliste.put(4, new Vocab("house", "das Haus"));
en_wortliste.put(5, new Vocab("dog", "der Hund"));
en_wortliste.put(6, new Vocab("small", "klein"));
en_wortliste.put(7, new Vocab("new", "neu"));
en_wortliste.put(8, new Vocab("grow", "wachsen"));
en_wortliste.put(9, new Vocab("fast", "schnell"));
en_wortliste.put(10, new Vocab("flower", "die Blume"));
en_wortliste.put(11, new Vocab("water", "das Wasser"));
en_wortliste.put(12, new Vocab("old", "alt"));
en_wortliste.put(13, new Vocab("table", "der Tisch"));
en_wortliste.put(14, new Vocab("hour", "die Stunde"));
en_wortliste.put(15, new Vocab("fresh", "frisch"));
en_wortliste.put(16, new Vocab("clock", "die Uhr"));
}
public HashMap<Integer, Vocab> getList()
{
return en_wortliste;
}
}import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.util.HashMap;
public class AufgabenVerteiler extends Actor
{
HashMap<Integer, Vocab> wordlist = new HashMap<Integer, Vocab>();
WordList words = new WordList();
private String word1;
private String word2;
private String word3;
private String word4;
private String taskField;
public AufgabenVerteiler()
{
wordlist = words.getList();
}
public void act()
{
if (Greenfoot.mouseClicked(this))
{
drawWords();
}
}
public void drawWords()
{
int random1 = getRandomNumber();
while (random1 == 0)
{
random1 = getRandomNumber();
}
int random2 = getRandomNumber();
while (random2 == random1 || random2 == 0)
{
random2 = getRandomNumber();
}
int random3 = getRandomNumber();
while (random3 == random1 || random3 == random2 || random3 == 0)
{
random3 = getRandomNumber();
}
int random4 = getRandomNumber();
while (random4 == random1 || random4 == random2 || random4 == random3 || random4 == 0)
{
random4 = getRandomNumber();
}
int taskRandom = Greenfoot.getRandomNumber(4);
while (taskRandom == 0)
{
taskRandom = Greenfoot.getRandomNumber(4);
}
switch(taskRandom)
{
case 1: taskField = wordlist.get(random1).getEnglish();
break;
case 2: taskField = wordlist.get(random2).getEnglish();
break;
case 3: taskField = wordlist.get(random3).getEnglish();
break;
case 4: taskField = wordlist.get(random4).getEnglish();
}
World myWorld = getWorld();
EnglishWorld english = (EnglishWorld)myWorld;
english.getWordField1().updateWordField(wordlist.get(random1).getDeutsch());
english.getWordField2().updateWordField(wordlist.get(random2).getDeutsch());
english.getWordField3().updateWordField(wordlist.get(random3).getDeutsch());
english.getWordField4().updateWordField(wordlist.get(random4).getDeutsch());
english.getTaskField().updateTask(taskField);
// System.out.println(word1 + ", " + word2 + ", " + word3 + ", " + word4);
}
public int getRandomNumber()
{
int random = Greenfoot.getRandomNumber(wordlist.size()+1);
return random;
}
}import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.util.HashMap;
public class OK extends Actor
{
HashMap<Integer, Vocab> wordlist = new HashMap<Integer, Vocab>();
AufgabenVerteiler verteiler = new AufgabenVerteiler();
public void act()
{
if (Greenfoot.mouseClicked(this))
{
verteiler.drawWords();
}
}
}