Question

我正在玩SwingWorker并学习使用它。所以，我有这段代码：

ArrayList<Train> dataList = new ArrayList<>();
ArrayList<Train> proccessedData = new ArrayList<>();

String query = "my query, not relevant here";

dataList = myApi.getTrainData(connectServer(), query, false);

TestNewThread tpp = new TestNewThread(dataList, threshold, pairs, false);

tpp.execute();

我的TestNewThread类是：

public class TestNewThread extends SwingWorker<List, String>{

    private ArrayList<Train> dataList;
    private int threshold
    private int pair
    private boolean processFurther) 

    MyAPI myApi = MyAPI.getInstance();

    public TestNewThread(ArrayList<Train> dataList, int threshold, int pair, boolean processFurther) {
        this.dataList = dataList;
        this.threshold = threshold
        this.pair = pair
        this.iprocessFurther)  = processFurther) 
    }

    @Override
    protected List doInBackground() throws Exception {

        ArrayList<Train> list;

        publish("Starting process");
        list = processingTrains(threshold, pair, dataList);
        publish("Process finished.");

        return list;
    }

    @Override
    protected void process(List<String> chunks) {
        String mostRecentValue = chunks.get(chunks.size() - 1);
        myApi.printPanel("\n"+mostRecentValue);
    }

    @Override
    protected void done() {
//        myApi .printPanel("\nALL DONE... !);
    }

现在我需要什么，我无法弄清楚如何做到这一点：在这里的第一个代码，我tpp.execute();我希望它返回到指定的变量。对于这样的事情，请注意评论部分：

ArrayList resultsList = new ArrayList();
TestNewThread tpp = new TestNewThread(dataList, threshold, pairs, false);
resultsList = tpp.execute(); // I know I can't do this because .execute() is void but I want something like whatever the new thread returns to return to resultsList array.

如果代码中有任何拼写错误或遗漏，我很抱歉，我现在就从头顶解释我的问题。我想你可以从这里得到这个想法。

Answer 1

SwingWorker的重点是能够异步执行某些操作，而不会阻塞EDT线程。因此，您无法从tpp.execute()返回任何内容，因为如果可以，那将意味着在后台任务完成之前EDT将被阻止，并且后台任务将不再是后台任务。< / p>

但是，您可以使用SwingWorker传递对组件的引用，并从done（）方法调用此组件的方法：

public class SomePanel extends JPanel {

    ...
    TestNewThread tpp = new TestNewThread(this, dataList, threshold, pairs, false);
    tpp.execute();

    ...

    public void backgroundTaskHasFinishedHereIsTheResult(List<Train> trains) {
        // TODO do whatever with the list of trains computed by the background task
    }
}

在SwingWorker子类中：

   private SomePanel somePanel;

   public TestNewThread(SomePanel somePanel, ArrayList<Train> dataList, int threshold, int pair, boolean processFurther) {
        this.somePanel = somePanel;
        ...
   }

   @Override
    protected void done() {
        List<Train> result = get();
        somePanel.backgroundTaskHasFinishedHereIsTheResult(result);
    }

返回或从SwingWorker线程获取/分配数据到变量。初学者

1 个答案: