如何在不冻结GUI的情况下调用SwingWorker .get()？

Question

我做了一个样本来澄清问题:

public class Worker extends SwingWorker<Integer, Integer> {
    private GeneralUserInterface gui;

    public Worker(GeneralUserInterface gui){
        this.gui = gui;
    }

    @Override
    protected Integer doInBackground() throws Exception {
        int someResultToReturn = 10;

        for(int i=0; i<100; i++){
            Thread.sleep(50);//The Work
            publish(i+1);//calls process, which updates GUI
        }

        return someResultToReturn;
    }

    @Override
    protected void process(List<Integer> values) {
        for (Integer val : values) {
            gui.updateProgressBar(val);
        }
    }
}

private void jButtonDoWorkActionPerformed(java.awt.event.ActionEvent evt) {
    Worker worker = new Worker(this);
    worker.execute();

    try {
        int resultToGet = worker.get();//Obviously freezes the GUI
    } catch (InterruptedException | ExecutionException ex) {}

    //NEXT LINE NEEDS THE RESULT TO CONTINUE
}

public void updateProgressBar(int value){
    this.jProgressBar1.setValue(value);
}

正如您所猜测的那样,对worker.get()的调用会使UI无响应,这是正常的,因为它等待线程完成.这种问题通常如何解决？

Answer 1

这种问题通常如何解决？

通常,您所做的是覆盖该Swingworker.done()方法.完成后台线程后,在GUI线程中执行完成.然后你可以安全地调用get而不会阻塞,并做任何你需要做的事情.

这是一种方法:

public class Worker extends SwingWorker<Integer, Integer> {
    private GeneralUserInterface gui;

    // omitted...

    @Override
    protected Integer doInBackground() throws Exception {
        int someResultToReturn = 10;

        for(int i=0; i<100; i++){
            Thread.sleep(50);//The Work
            publish(i+1);//calls process, which updates GUI
        }

        return someResultToReturn;
    }

    // omitted...

    @Override
    protected void done() {

        try {
           int resultToGet = worker.get();//Obviously freezes the GUI
        } catch (InterruptedException | ExecutionException ex) {}

       //NEXT LINE NEEDS THE RESULT TO CONTINUE
   }
}

private void jButtonDoWorkActionPerformed(java.awt.event.ActionEvent evt) {
    Worker worker = new Worker(this);
    worker.execute();
}

然而,这可能不是最方便的设计.我发现最好让GUI东西成为公共类,然后将swing工作者创建为非静态内部类.这样,"完成"方法可以轻松访问所有GUI私有变量.