java - 从另一个类获取数组

Question

我正在写论文，需要帮助。我的论文的一部分是我需要创建一个游戏选择器，我的连接类型是蓝牙，客户端是Android手机，服务器是java。我使用 JFileChooser 来获取数组的值，我需要将该数组传递给另一个类。我尝试关注这篇文章http://www.dreaminco...ifferent-class/但在我的程序中，我似乎无法让它工作，这是我的代码:

DemoJFileChooser(我将获取路径[]数组的类)

package com.luugiathuy.apps.remotebluetooth;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.File;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class DemoJFileChooser extends JPanel implements ActionListener {
   JButton go;

   JFileChooser chooser;
   String choosertitle;
   public int x=0;
   public String path[] = new String[10];

  public DemoJFileChooser() {
    go = new JButton("Do it");
    go.addActionListener(this);
    add(go);
   }

   public Dimension getPreferredSize(){
    return new Dimension(200, 200);
    }

  public static void main(String s[]) {
      Thread waitThread = new Thread(new WaitThread());
        waitThread.start();

    JFrame frame = new JFrame("");
    DemoJFileChooser panel = new DemoJFileChooser();
    frame.addWindowListener(
      new WindowAdapter() {
        public void windowClosing(WindowEvent e) {
          System.exit(0);
          }
        }
      );
    frame.getContentPane().add(panel,"Center");
    frame.setSize(panel.getPreferredSize());
    frame.setVisible(true);
    }

@Override
public void actionPerformed(ActionEvent arg0) {
    // TODO Auto-generated method stub
    int result;

    chooser = new JFileChooser(); 
    chooser.setCurrentDirectory(new java.io.File("."));
    chooser.setDialogTitle(choosertitle);
    chooser.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
       //
    // disable the "All files" option.
    //
    chooser.setAcceptAllFileFilterUsed(false);
    //    

    if (chooser.showOpenDialog(this) == JFileChooser.APPROVE_OPTION) { 
      System.out.println("getCurrentDirectory(): " 
         +  chooser.getCurrentDirectory());
      System.out.println("getSelectedFile() : " 
         +  chooser.getSelectedFile());

          File paths = chooser.getSelectedFile();
          path[x] = paths.getAbsoluteFile().toString();
          x++; 

    for (int y=0;y<9;y++){
          System.out.println(path[y]);
          setArray(path);

    }
    }
    else {
      System.out.println("No Selection ");
      }

}
    void setArray(String paths[]) { // saves surname to variable
             path= paths; 

    }

    String[] getArray() { //gets the surname when called
          return path;
    }
}

ProcessConnectionThread(我需要数组的类)

package com.luugiathuy.apps.remotebluetooth;

import java.awt.MouseInfo;
import java.awt.Point;
import java.awt.PointerInfo;
import java.awt.Robot;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.io.InputStream;
import java.io.OutputStream;
import com.luugiathuy.apps.remotebluetooth.DemoJFileChooser;


import javax.microedition.io.StreamConnection;

public class ProcessConnectionThread implements Runnable{
    //DemoJFileChooser path;
    //public String[] path = new String[10];

    private StreamConnection mConnection;

    // Constant that indicate command from devices
    //private static final int EXIT_CMD = -1;
    private static final int STEER_RIGHT = 1;
    private static final int STEER_LEFT = 2;
    private static final int ACCE = 3;
    private static final int REV = 4;
    private static final int MOVE = 5;
    private static final int LEFT_CLICK = 6;
    private static final int DOUBLE_CLICK = 7;
    private static final int RIGHT_CLICK = 8;
    private static final int HOLD = 9;
    private static final int RELEASE = 10;
    private static final int MOVEX = 11;
    private static final int MOVEY = 12;
    private static final int GAME = 20;
    private static final int GAME1 = 11;
    private static final int GAME2 = 12;
    private static final int GAME3 = 13;
    private static final int GAME4 = 14;
    private static final int GAME5 = 15;
    private DemoJFileChooser patharray[] = new DemoJFileChooser[10]; //create object array from student class

    public ProcessConnectionThread(StreamConnection connection)
    {
        mConnection = connection;
    }

    public void FileChooser() { //constructor use keyword public just to make sure it is visible
        for (int studI=0;studI<10;studI++) {
            patharray[studI] = new DemoJFileChooser();
        }
    } 
    @Override
    public void run() {
        try {

            // prepare to receive data
            InputStream inputStream = mConnection.openInputStream();
            OutputStream outputStream = mConnection.openOutputStream();
            System.out.println("waiting for input");

            while (true) {
                int command = inputStream.read();
                System.out.println(command);

                processCommand(command);

            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * Process the command from client
     * @param command the command code
     */
    private void processCommand(int command) {
        try {


            case GAME1:
                for (int y=0;y<10;y++){
                      patharray[y].getArray();
                      System.out.println(patharray[y]);
                }
                Process p = Runtime.getRuntime().exec(patharray[0]);
                p.waitFor();



                break;


            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    }

我在 for 循环、patharray[] 上遇到错误。

任何帮助/建议将不胜感激。谢谢。

Answer 1

创建数组深拷贝的最简单方法是使用内置 Arrays.copyOf函数族。

例如:

String [] srcArray = { "item 1", "item 2", "item 3" };
String [] copy = Arrays.copyOf(srcArray, srcArray.length);

就您的代码而言，存在一些问题。在 DemoJFileChooser.actionPerformed您始终通过 System.out.println 打印路径数组的所有 10 个元素，但不能保证所有这些元素中都存在一个对象。您可能会在这里收到 NullPointerException。您的 for 循环应限制为 x 。另外，在该循环中您正在调用 setArray(path)这意味着您无缘无故地调用该函数 10 次。另外，你真的在​​做path = path因为你正在通过path进入setArray它分配给路径。

您还应该检查 x没有超过 path 的大小当您使用 path[x] = paths.getAbsoluteFile().toString(); 分配给它时.

作为一个单独的建议，而不是做 for(int i=0; i<10; i++) {...}每当您迭代数组时，您可能希望使用 for(int i=0; i<theArray.length; i++) {...}这样，如果您更改了数组大小，则无需更新整个程序中的 for 循环。