Java扫描程序问题（JFrame） [英] Java Scanner issues (JFrame)
本文介绍了Java扫描程序问题（JFrame）的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试使用扫描仪编辑塔防游戏的等级。但是它不会将级别（平铺图像）更新为自定义文件的级别（0是草1是石头-1是什么，等等）。我发现了错误但我该如何修复它，我需要添加/更改什么来摆脱这个？
I am trying to use a scanner to edit the level of my tower defense game. However it will not update the level (the tile images) to that of the custom file (0 is grass 1 is stone -1 is nothing, etc.). I have found the error but how do i fix it, what do i need to add/change to get rid of this?
java.lang.NullPointerException
at Levels.loadLevels(Levels.java:11)
at Window.define(Window.java:28)
at Window.paintComponent(Window.java:44)
第11行： for（int y = 0; y< Window.room .block.length; y ++）{
第28行： levels.loadLevels（新文件（levels / level1.level））;
第44行： define（）;
这是扫描文件：
import java.io.*;
import java.util.*;
public class Levels {
public void loadLevels(File loadPath) {
try {
Scanner loadLevelsScanner = new Scanner(loadPath);
while(loadLevelsScanner.hasNext()) {
for(int y=0;y<Window.room.block.length;y++) {
for(int x=0;x<Window.room.block[0].length;x++) {
Window.room.block[y][x].groundID = loadLevelsScanner.nextInt();
}
}
for(int y=0;y<Window.room.block.length;y++) {
for(int x=0;x<Window.room.block[0].length;x++) {
Window.room.block[y][x].airID = loadLevelsScanner.nextInt();
}
}
}
loadLevelsScanner.close();
} catch(Exception e) {
}
}
}
这是窗口文件：
import javax.swing.*;
import java.awt.*;
import java.awt.image.*;
import java.io.*;
public class Window extends JPanel implements Runnable {
public Thread thread = new Thread(this);
public static Image[] tileset_ground = new Image[100];
public static Image[] tileset_air = new Image[100];
public static int myWidth, myHeight;
public static boolean isFirst = true;
public static Room room;
public static Levels levels;
public Window() {
thread.start();
}
public void define() {
room = new Room();
levels = new Levels();
levels.loadLevels(new File("levels/level1.level"));
for(int i=0;i<tileset_ground.length; i++) {
tileset_ground[i] = new ImageIcon("resources/tileset_ground.png").getImage();
tileset_ground[i] = createImage(new FilteredImageSource(tileset_ground[i].getSource(), new CropImageFilter(0, 32 * i, 32, 32)));
}
for(int i=0;i<tileset_air.length; i++) {
tileset_air[i] = new ImageIcon("resources/tileset_air.png").getImage();
tileset_air[i] = createImage(new FilteredImageSource(tileset_air[i].getSource(), new CropImageFilter(0, 32 * i, 32, 32)));
}
}
public void paintComponent(Graphics g) {
if(isFirst) {
define();
isFirst = false;
}
g.clearRect(0, 0, getWidth(), getHeight());
room.draw(g);
}
public void run() {
while(true) {
if(!isFirst) {
room.physic();
}
repaint();
try {
Thread.sleep(1);
} catch(Exception e) {
}
}
}
}
这是房间文件：
import java.awt.*;
public class Room {
public int worldWidth = 40;
public int worldHeight = 20;
public int blockSize = 32;
public Block[][] block;
public Room () { }
public void define () { }
public void physic () { }
public void draw(Graphics g) {
block = new Block[worldHeight][worldWidth];
for(int y=0;y<block.length;y++) {
for(int x=0;x<block[0].length;x++) {
block[y][x] = new Block(x * blockSize, y * blockSize, blockSize, blockSize, Value.groundGrass, Value.airAir);
block[y][x].draw(g);
}
}
}
}
this是块文件：
import java.awt.*;
public class Block extends Rectangle {
public int groundID;
public int airID;
public Block(int x, int y, int width, int height, int groundID, int airID) {
setBounds(x, y, width, height);
this.groundID = groundID;
this.airID = airID;
}
public void draw(Graphics g) {
g.drawImage(Window.tileset_ground[groundID], x, y, width, height, null);
if(airID != Value.airAir) {
g.drawImage(Window.tileset_air[airID], x, y, width, height, null);
}
}
}
最后这是自定义文件扫描仪应该读取：
And lastly this is the custom file the scanner is supposed to read:
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
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-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
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-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
抱歉这个愚蠢的问题，我是初学者。
sorry for the stupid question, i'm a beginner.
推荐答案
一个快速而肮脏的解决方案是，测试Window.room不为null，以及.block：
A quick-and-dirty solution is, to test for Window.room not to be null, as well as .block:
Scanner loadLevelsScanner = new Scanner (loadPath);
if ((Window.room != null) &&
(Window.room.block != null)) {
// ... block until catch block
}
一个简单的Testapp我写的作品到目前为止，如果这样做了。
A simple Testapp I've written works so far, if done so.
但是你需要了解静态是什么，以及为什么以及如何使用它。一个常见的初学者错误是，为了使编译器保持沉默而使用静态关键字。
But you need to understand what "static" is, and why and how to use it. A common beginner mistake is, to instert "static" keywords just to make the compiler silent.
调查，按顺序初始化您的类及其属性。
Investigate, in which order to initialize your classes and their attributes.
在Block中，要访问Window，您必须有一个引用。该引用可以传递给Block的ctor：
In Block, to access the Window, you have to have a reference. The reference can be passed to the ctor of Block:
class Block extends Rectangle {
public int groundID;
public int airID;
Window window;
public Block (int x, int y, int width, int height, int groundID, int airID, Window window) {
setBounds (x, y, width, height);
this.groundID = groundID;
this.airID = airID;
this.window = window;
}
public void draw (Graphics g) {
g.drawImage (window.tileset_ground [groundID], x, y, width, height, null);
if (airID != Value.airAir) {
g.drawImage (window.tileset_air [airID], x, y, width, height, null);
}
}
}
谁创建了块？这是Room，所以Room本身需要了解Window（只要你不从根本上改变你的设计）。
Who creates Blocks? It is Room, so Room itself needs to know about the Window (as long as you don't change your design fundamentally).
public Room (Window w) {
block = new Block [worldHeight] [worldWidth];
for (int y=0; y <block.length; y++) {
for (int x=0; x <block [0].length; x++) {
block [y] [x] = new Block (x * blockSize, y * blockSize, blockSize, blockSize, Value.groundGrass, Value.airAir, w);
}
}
}
创建一个块数组，初始化，块传递Window参数。
A block array is created, initialized, and the Blocks are passed the Window-parameter.
在绘制中，你不会一遍又一遍地重新创建数组，也不重新创建块，只是重绘它们：
In draw, you don't recreate the array over and over again, nor do you recreate the Blocks, but just redraw them:
public void draw (Graphics g) {
for (int y=0; y <block.length; y++) {
for (int x=0; x <block [0].length; x++) {
block [y] [x].draw (g);
}
}
}
在Window中，您创建了房间，并传递窗口参考：
In Window, you create the Room, and pass it the window-reference:
public void define () {
room = new Room (this);
levels = new Levels ();
这篇关于Java扫描程序问题（JFrame）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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