Java GUI 不会显示

Question

我目前正在开发一个使用树莓派全屏显示的程序，当我在 Eclipse“在 pi 上”运行这个程序时，它工作正常，看起来像这样

但是当我将文件导出到可运行的 jar 时，会发生这种情况

但我没有收到任何错误，它也没有关闭，它只是显示窗口，但没有任何反应。

这是您看到的框架的代码，

package Main;

import java.awt.Button;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Toolkit;
import java.io.IOException;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Tester extends JFrame {

// R3T Object
r3t R3T = new r3t();

// Random Stuff
public static boolean updateMe = false;
private int count = 0;
public static int R3TCount = 0;

private ImageIcon tank_full = new ImageIcon("src/res/level.png");
private ImageIcon tank_empty = new ImageIcon("src/res/tank_empty.png");

// For drawing the rectangle Y = NON DEFAULT
public static int NDRECT_Y = -0;
public static int TankValue = -0;
public static String TankLevel = "0.0";

//RATIOS
private int X1 = (int)(WIDTH * 0.06);
private int Y1 = (int)(HEIGHT * 0.111);
private int Y2 = (int)(HEIGHT * 0.781);

//Screen
public static Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
public static  int WIDTH = (int)screenSize.getWidth();
public static int HEIGHT = (int)screenSize.getHeight();


public Tester() {
    //Screen Size
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.setResizable(false);
    this.setTitle("Tank Level");
    this.setUndecorated(true);
    this.setLocation(0, 0);
    this.setSize(new Dimension(WIDTH, HEIGHT));
    this.setVisible(true);
}

public void paint(Graphics g) {

    g.drawImage(tank_empty.getImage(), 0, 0, WIDTH, HEIGHT, this);

    // REMINDER : x , y, x, y
    g.drawImage(tank_full.getImage(), X1, Y1, TankValue, Y2, this);

    drawTankLevel(g);
    g.dispose();
    doTask();
    count += 1;
}

public void drawTankLevel(Graphics temp) {
    temp.setFont(new Font("Vendana", 0, 30));
    temp.drawString("        ", (WIDTH / 2) - 20, (HEIGHT / 2));
    temp.drawString(TankLevel, (WIDTH / 2)- 20, (HEIGHT / 2));
    temp.dispose();
}

public static void updateTankLevel(double level) {
    TankValue = (int) ((WIDTH * level / 100) - (WIDTH * 0.12));
    TankLevel = String.valueOf(level);
}

public static double getTankLevel() {
    return Double.parseDouble(TankLevel);
}

public void doTask() {
    if (count == 0) {
        Thread t = new Thread(new Runnable() {

            public void run() {
                while (true) {
                    try {
                        Thread.sleep(2500);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    try {
                        System.out.println();
                        System.out.println ("CNT: "+R3TCount);
                        System.out.println ("-----------------");

                        R3T.GetDeviceInfo();
                        R3TCount += 1;
                        repaint();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        System.out.println("ERROR: " + e.getMessage());
                    } catch (InterruptedException t) {
                        System.out.println("ERROR: " + t.getMessage());
                    }
                }
            }
        });
        t.start();
        repaint();
    }

    if (updateMe) {
        System.out.println("R3T: Updated Guage!");
        updateMe = false;
    }
}

public static void main(String[] args) {
    Tester test = new Tester();
}
}

这是更改值的代码，它是蓝牙扫描并获取设备的名称，我知道这工作正常，因为它打印了值，只是不在屏幕上更新它

public void calculateTankLevel(String tempDevice) {
    String deviceName = tempDevice.substring(18, tempDevice.length());

    int byt_div = 0xE005;
    int num_div = 10;
    byte[] valueRay;

    valueRay = hexStringToByteArray(deviceName.substring(deviceName.length() - 4, deviceName.length()));

    double value = twoBytesToShort(valueRay[0], valueRay[1]);
    double val = ((value - byt_div) / num_div);

    System.out.println ("R3T: Calculated Tank Level");

    if (val == Tester.getTankLevel()) {
        //The value hasnt change dont update.
        System.out.println ("R3T: Tank Level *NU*");
    } else {
        //Value has changed update UI and send to webservice
        //R3TWebCall.sendTankLevel(val);
        System.out.println("Tank Level: "+val);
        Tester.updateTankLevel(val);
        Tester.updateMe = true;
    }
}

我在代码中添加了另一部分，就是这样。

File f = new File("res/level.png");
    if(f.exists() && !f.isDirectory()) { 
        System.out.println("TANK FULL EXISTS");
    } else {
        System.out.println("TANK FULL DOES NOT EXISTS");
    }

    File f1 = new File("res/tank_empty.png");
    if(f1.exists() && !f.isDirectory()) { 
        System.out.println("TANK EMPTY EXIST");
    } else {
        System.out.println("TANK FULL DOES NOT EXISTS");
    }

添加此命令后，它会告诉我查找它的时间是否存在，当我在 Eclipse 中运行它时，它会说文件确实存在，但是!当我导出到 jar 文件时，它说它不存在!

Answer 1

我很久以前就遇到过这个问题，您可能没有将资源文件夹声明为“类文件夹”。右键单击您的项目，然后转到属性，然后转到 java 构建路径，然后单击“添加类文件夹”。将弹出一个窗口，通过选中复选框选择您的资源文件夹“res”。您可能还需要修改您的路径。

还将你的 res 文件夹移到 src 文件夹之外，src 文件夹仅用于代码源，而不用于资源。要加载资源，您还可以使用 MyClass.class.getRessourceAsStream("path");