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Alrighty，這裏第一篇文章使我大喊如果我做錯了什麼，但我有以下代碼，嘗試是使一個區域建造一種交易的那些老的一個學校圈泥。但是我不斷收到一些空指針錯誤。我一派，並修改了對這個問題小時，我想是時候給別的東西一試：P的Java空指針異常的多維數組
這樣做的目的是創建一個三維數組存儲室的實例。如果您熟悉泥地的房間有一系列詞綴，特別是這個詞彙的三維網格，每個房間的座標都可以通過圖形的藝術標籤。該陣列然後將被用於顯示JPanel上每個高度的地板的二維網格，其中標籤圖片基於房間的出口狀態。問題似乎是，要麼是a。構造函數沒有設置我似乎不太可能的變量b。我用它錯了（很可能因爲我不熟悉java）或c。我忽略了一些非常容易的錯誤。
的誤差隨時來我嘗試了房間類中訪問變量。
package battle.org;
public class GUI extends JFrame {
public class Rooms{
String Rt;
String desc;
boolean dark;
boolean indoors;
boolean nomob;
boolean peace;
boolean soundproof;
boolean notrack;
boolean nomag;
boolean tunnel;
boolean notify;
boolean SF;
boolean FF;
boolean noport;
boolean noquit;
boolean exitu;
boolean exitd;
boolean onmap;
boolean exitud;
boolean exite;
boolean exitw;
boolean exits;
boolean exitn;
public Rooms(){
String Rt = "Room Name";
String desc = "Default Description";
dark = false;
indoors = false;
nomob = false;
peace = false;
soundproof = false;
notrack = false;
nomag = false;
tunnel = false;
notify = false;
SF = false;
FF = false;
noport = false;
noquit = false;
exitu = false;
exitd = false;
onmap = false;
exitud = false;
exite = false;
exitw = false;
exits = false;
exitn = false;
}
}
private JPanel contentPane;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
GUI frame = new GUI();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public GUI() {
final int MAXxy = 10;
final int MAXz = 1;
int z;
Rooms[][][] a = new Rooms[MAXxy][MAXxy][MAXz];
// for(int x = 0; x < MAXxy; x++){
// for(int y = 0; y < MAXxy ; y++){
// for(z = 0; z < MAXz; z++){
// a[x][y][z] = new Rooms();
// }
// }
// }
//Labels to be displayed in grid
JLabel room = new JLabel(new ImageIcon("C:\\Users\\Owner\\Desktop\\room.jpg"));
JLabel nothing = new JLabel(new ImageIcon("C:\\Users\\Owner\\Desktop\\empty.jpg"));
JLabel up = new JLabel(new ImageIcon("C:\\Users\\Owner\\Desktop\\up.jpg"));
JLabel down = new JLabel(new ImageIcon("C:\\Users\\Owner\\Desktop\\down.jpg"));
//Error here wont let me access the boolean
a[0][0][0].onmap = true;
int x, y;
x =0; y =0; z = 0;
if(a[0][0][0].onmap){
System.out.print("X = " + x + " Y = " + y + " Z = " + z + "");
contentPane.add(down, new GridBagConstraints(x, y, 1, 1, 0.0, 0.0 ,GridBagConstraints.NORTHWEST, GridBagConstraints.NONE, new Insets(0, 0, 0, 0), 0, 0));
}
//Displays Altitude level z
z = 0;
/* for(int x = 0; x < MAXxy; x++){
for(int y = 0; y < MAXxy ; y++){
if(a[0][0][0].onmap){
contentPane.add(down, new GridBagConstraints(x, y, 1, 1, 0.0, 0.0 ,GridBagConstraints.NORTHWEST, GridBagConstraints.NONE, new Insets(0, 0, 0, 0), 0, 0));
}
}
}*/
}
}
錯誤列表：
java.lang.NullPointerException
at battle.org.GUI.<init>(GUI.java:189)
at battle.org.GUI$1.run(GUI.java:77)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
GUI frame = new GUI（）;是線77 – Phenom