Question

我有一个带有此函数的JFrame类：

o=1;
private String performTest(int i,File file) throws IOException, InterruptedException {
        //CRAPPY CODE  
               while(o<=20) {
               Thread.sleep(1000); 
               progressBar.setValue((o/20)*100);              
               o++;
               }
        //CRAPPY CODE
    }

因此，进度条应该每秒都以更大的值更新，但是我得到的只是最后一次更新（到100），当函数完成它的工作时; 也许有一些方法可以解决这个问题？谢谢你。完整代码。

   btnTesteaz.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            int i = choice.getSelectedIndex();
            File file = fc.getSelectedFile();


            StringBuilder builder = new StringBuilder();        
            Thread t = new Thread(new Runnable() {
                @Override
                public void run() {

                        String name = Problems[i];
                        int o = 1;
                        try {

                        String pathToPas = file.getPath();
                        String pathToExe = pathToPas.replace(".pas", ".exe");
                        Process process = Runtime.getRuntime().exec("ppc386  "+pathToPas);
                        Thread.sleep(1000);
                        process.destroy();

                        while (new File("Res\\"+Problems[i]+"\\"+"Input"+o+".txt").exists()) { 
                            //FILES WITH INPUTS FROM RES
                            File in = new File("Res\\"+Problems[i]+"\\"+"Input"+o+".txt");
                            //FILES FOR .PAS
                            File inputtxt = new File(file.getParent()+"\\Input.txt");



                            BufferedReader bf = new BufferedReader(new FileReader(in));
                            PrintWriter w = new PrintWriter(new FileWriter(inputtxt));     
                            String s = null;
                            while ((s = bf.readLine())!=null)    {
                                w.println(s);
                            }
                            w.close();        
                            bf.close();
                            Process process1 = Runtime.getRuntime().exec(pathToExe,null, new File(file.getParent()));
                            Thread.sleep(1000);
                            process1.destroy();

                            File outputtxt = new File(file.getParent()+"\\Output.txt");
                            File out = new File("Res\\"+Problems[i]+"\\"+"Output"+o+".txt");
                            BufferedReader r1 = new BufferedReader(new FileReader(out)); 
                            BufferedReader r2 = new BufferedReader(new FileReader(outputtxt));                
                            StringBuilder ansRes = new StringBuilder();
                            StringBuilder ansPas = new StringBuilder();     
                                while ( (s=r1.readLine())!=null) ansRes.append(s);
                                while ( (s=r2.readLine())!=null) ansPas.append(s);

                            if (ansRes.toString().trim().equals(ansPas.toString().trim()))  {
                                builder.append("<p font color=green>"+(o)+". Test succesful </p> ") ;
                            }
                            else builder.append("<p font color=red>"+(o)+". Test failed </p>");
                            r1.close();
                            r2.close();

                               inputtxt.delete();
                               outputtxt.delete();

                               final int temp = o;
                               SwingUtilities.invokeLater(new Runnable() {
                                   public void run() {
                                       model.setValue((int) (((float) temp / 20.0f) * 100));
                                   }
                               });                               
                               o++;
                        }
                        File f = new File(pathToExe);
                        f.delete();
                        File fa = new File(file.getAbsolutePath().replace(".pas",".o"));
                        fa.delete();
                        }
                        catch (Exception e) {
                            e.printStackTrace();
                        }
                }
            });
            t.run();
        Result.setText(builder.toString());
        }
    });

Answer 1

在Swing中这是一个经典问题。 Swing从其主线程中进行所有图形更新，因此您不应该从那里进行长时间操作（您不会让它重新绘制！）

尝试将您的长时间操作转移到本教程中的另一个线程：

https://docs.oracle.com/javase/tutorial/uiswing/concurrency/worker.html

这将教你如何在后台进行长时间的任务，同时实时更新你的UI而不会搞乱Swing架构

Answer 2

添加到Swing UI冻结问题，您还会分配两个整数，这些整数总是向下舍入到最接近的整数，因此您每次都要将进度条设置为0*100，除了上一次{ {1}}，除了使用线程之外，将o == 20强制转换为o并通过float进行转换应该可以解决问题：

20.0f

Answer 3

尝试将int更改为double

double o=1;
final double max = 100.00;
final double per = 20.00
private String performTest(int i,File file) throws IOException, InterruptedException {
        //HAPPY CODE  
        while(o<=20) {
            Thread.sleep(1000); 
            progressBar.setValue( (int)((o/per)*max) );              
            o++;
        }
        //HAPPY CODE
 }

JProgressBar不会动态更新

3 个答案: