为什么第二个JFrame不显示组件? [英] Why does the second JFrame does not show components?

问题描述

我有第一个JFrame，它工作正常.当我按下按钮时，它应该显示一个JProgressBar框架，但是我得到的是空的JFrame.我用

I have the first JFrame and it works fine. When I push a button it is supposed to show a JProgressBar frame , but i get empty JFrame. I open it with

                p = new Progress("1/3");
                p.setMax(2);
                p.setProgress(0, "Getting bytes...");

有人知道为什么吗?

我将解释更多细节(因为有人误解并以错误的方式纠正了我的帖子)-在我的主类中，我启动了第一个JFrame: new Crypt(); 在Crypt类中，我注册了一个按钮ActionListener. OnClick会打开第二个JFrame ，但它为空:

I am going to explain more detail(Because someone misunderstood and corrected my post in the wrong way) - On my main class i start the first JFrame: new Crypt(); And in the Crypt class i have registered a button ActionListener. OnClick it opens a second JFrame But it is empty:

                p = new Progress("1/3");
                p.setMax(2);
                p.setProgress(0, "Getting bytes...");

进度类 屏幕截图

推荐答案

在地穴类中，我注册了一个按钮ActionListener. OnClick会打开第二个JFrame，但它为空

in the Crypt class i have registered a button ActionListener. OnClick it opens a second JFrame But it is empty

从Swing侦听器调用的

代码在Event Dispatch Thread (EDT)上执行. EDT负责绘制Swing组件.由于您的代码正在EDT y9ou上执行长时间运行的任务，因此在任务完成之前，Swing无法绘画组件.

Code invoked from an Swing listener executes on the Event Dispatch Thread (EDT). The EDT is responsible for painting Swing components. Since your code is executing a long running task on the EDT y9ou are preventing Swing from painting the component until the task is finished.

您需要为长期运行的任务启动一个单独的线程.或者更好的是，您可能应该使用SwingWorker.阅读有关 Swing中的并发的Swing教程中的部分，其中介绍了对此进行了更详细的介绍，并提供了一个SwingWorker的工作示例.

You need to start a separate Thread for your long running task. Or better yet you should probably be using a SwingWorker. Read the section from the Swing tutorial on Concurrency in Swing which explains this in more detail and provides a working example of a SwingWorker.

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