JFrame打开为空 [英] JFrame opening empty

问题描述

我正在尝试创建一个程序，它在JFrame中没有显示任何内容，这很奇怪.该代码似乎合适，但Java似乎很混乱.到目前为止，这是我的代码:

I'm trying to create a program and it's not showing anything in JFrame which is rather odd. The code seems to fit but java appears to be confused or something. Here's my code so far:

import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.io.IOException;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;


public class Img extends JFrame{

/**
 * 
 */
private static final long serialVersionUID = -6362332275268668673L;
static JFrame panel = new JFrame();
private JButton next= new JButton("Next");

public Img(String a, String b){
    ShowPng1(a,b);
}

public void ShowPng1(String a, String b) {
    ImageIcon theImage = new ImageIcon("Icon_Entry_21.png");
    panel.setSize(300, 300);
    panel.setResizable(false);

    JLabel label = new JLabel(a);
    JLabel label2 = null;
    if(!b.isEmpty()){
        label2 = new JLabel("NOTE: " + b);
    }

    JLabel imageLabel = new JLabel(theImage);
    imageLabel.setOpaque(true);

    JPanel p1 = new JPanel(new GridLayout(3, 1));
    p1.add(imageLabel);
    p1.add(label);
    if(label2 != null)p1.add(label2);

    panel.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    panel.setVisible(true);
}

public void ShowPng2(String a, String b) {
    ImageIcon theImage = new ImageIcon("Icon_Entry_21.png");
    panel.setSize(300, 300);
    panel.setResizable(false);

    JLabel label = new JLabel(a);
    JLabel label2 = null;
    if(!b.isEmpty()){
        label2 = new JLabel("NOTE: " + b);
    }

    JLabel imageLabel = new JLabel(theImage);
    imageLabel.setOpaque(true);

    JPanel p1 = new JPanel(new GridLayout(3, 1));
    p1.add(imageLabel);
    p1.add(label);
    if(label2 != null)p1.add(label2);
    p1.add(next);

    panel.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    panel.setVisible(true);

    try {
        Runtime.getRuntime().exec("cmd /c start mailrugames://play/0.3001");
    } catch (IOException e) {
        JOptionPane.showMessageDialog(null, "Error launching client.","Error", JOptionPane.ERROR_MESSAGE);
        System.exit(-1);
    }

}

public void actionPerformed(ActionEvent e) {
    try {
        ShowPng1("Applying patch NOW.","");
        Process p1 = Runtime.getRuntime().exec("cmd /c start Start.bat");
        p1.waitFor();
        JOptionPane.showMessageDialog(null, "Done!","Note", JOptionPane.INFORMATION_MESSAGE);
        System.exit(0);
    } catch (IOException e1) {
        e1.printStackTrace();
        System.exit(-1);
    } catch (InterruptedException e1) {
        e1.printStackTrace();
        System.exit(-1);
    }
}

public static void main(String[] args) throws IOException, InterruptedException {

    Img i = new Img("Preparing client for a patch","");
    Process p1 = Runtime.getRuntime().exec("cmd /c start Clean.bat");
    p1.waitFor();
    Img.panel.dispose();

    i.ShowPng2("Launching client.","Make sure the client is fully patched before closing it and clicking `Next`");      
}
}

它应该将图像imageLabel加载到容器中，并在底部显示一些文本label和label2. ShowPng1()和ShowPng2()之间的区别是下一步"按钮，它位于ShowPng2()中.

It should load an Image imageLabel into a container and show some text label and label2 on the bottom. The difference between ShowPng1() and ShowPng2() is the Next button, it's located in ShowPng2().

推荐答案

1)您不是要向JFrame本身添加组件.您忘记添加

1) You are not adding components to the JFrame itself. You forget to add

public class Img extends JFrame{
  .
  .
  public void ShowPng1(String a, String b) {       
       //your code here, don't call panel.setVisible(true) here is not necesary
       this.add(panel);
  }

}

2)不必调用panel.setVisible(true)，没有必要..只需在main中调用i.setVisible(true).

2) Don't call panel.setVisible(true) it's not necessary.. just call i.setVisible(true) in main.

3)为确保您的代码在事件分发线程中运行，请使用SwingUtilities.invokeLater(..)

3)To ensure that your code is running in the event dispatch thread wrap it with SwingUtilities.invokeLater(..)

4)如果这是一项长期运行的任务，则应在后台线程中执行命令，否则将阻塞gui.在并发并发

4)You should execute your command in a background thread if it's a long running task cause if not you will block your gui. Read more in Concurrency in swing

5)遵循Java代码约定，方法名称以驼峰样式的小写字母开头.

5) Follow Java code conventions, method names starts with lower-case with a camel style.

6)也遵循@HovercraftFullOfEels的建议.

6) Follow @HovercraftFullOfEels advices too.

看看 Swing教程

这篇关于JFrame打开为空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！