java - 更改另一个类的 UI 值

Question

我正在 Java 中实现消费者-生产者问题，我需要为此添加家伙。我的问题是从 Customer 或 Producer 类更改 UI 组件。

我不知道如何从其他不相关的类中调用这些组件。当我尝试获取例如组件的高度时，一切都像魅力一样工作，但是当我尝试设置任何东西时，什么也没有发生!

这是我的 Producer 类代码，进行了一些尝试:

public class Producer extends Thread {
    // Variable which holds shared queue
    private BlockingQueue<String> queue;
    // Amount products created by producer
    private int steps;
    // Object with normaln distribution
    private NormalDistribution distribution;

    // Accessors to the frame
    private PCPMainFrame frame;
    private JSlider queueSlider;
    private JProgressBar queueProgressBar;

    // Constructor with 4 arguments
    // q                    - is our queue shared between customer and producer
    // steps                - amount of products
    // mean                 - parameter rquired for normal distribution
    // standardDeviation    - ditto
    public Producer(BlockingQueue<String> q, int steps, double mean, double standardDeviation){
        this.queue=q;
        this.steps = steps;
        this.distribution = new NormalDistribution(mean, standardDeviation);
        this.frame = new PCPMainFrame();
        this.queueSlider = frame.getQueueSlider();
        this.queueProgressBar = new JProgressBar();
    }

    @Override
    public void run() {
        // Generating products and filling queue with them
        for(int i = 0; i < steps; i++){
            try {
                long sleepTime = Math.abs((long)distribution.sample()*100);
                Thread.sleep(sleepTime);
                // Saving element in queue
                queue.put(String.valueOf(i));
                // This is a log for developer needs, feel free to uncomment
                System.out.println("Produced: " + i);
                queueSlider.setValue(steps);
                frame.setQueueProgressBar(queueProgressBar);
            } catch (InterruptedException e) {
                System.out.println("Producer exception: " + e);
            }
        }
        // Ading exit message at the end of the queue
        String exit = new String("exit");
        try {
            queue.put(exit);
        } catch (InterruptedException e) {
            System.out.println("Queue exception: " + e);
        }
    }
}

Answer 1

为了修改事件调度线程之外的 GUI 外观，您有几个选择。您可以使用 SwingUtilities.invokeLater 并传递一个 Runnable 来执行您的任务，或者使用 SwingWorker。