Java Swing : repaint component during long event

Question

我正在使用 Java Swing 为应用程序呈现我的 GUI。我在 JButton 上设置了一个 ActionListener 来触发一系列测试。理想情况下，我想用实时测试信息和结果更新状态区域(当前是 JTextArea)。换句话说，程序会在测试运行和完成时逐行设置文本区域，如下所示:

Running Tests...     Test 1:  Check Something...         Success    Test 2:  Check Something else...         Success    ..    //More testing outputAll tests have completed successfully.  Yay.

The problem is that I can't get the status text to update while my actionPerformed event method is still running. This is is all fine and dandy when all of the tests complete quickly. However, some of my tests take an indefinite amount of time to complete (think "database connection timeout"). When this happens, users are stuck with whatever text was already in the status area and my application freezes until the tests complete or fail.

I've tried calling repaint on my JTextArea every time I update the status, but it seems that just adds it to the event queue (which won't get fired till after my actionPerformed event completes...doh). I've also tried calling revalidate and updateUI, and even tried calling wait() on the ActionListener class running my tests, but nothing has worked thus far. Here is the structure of my current code:

..

JTextArea statusOutput_textArea;

..

public void actionPerformed(ActionEvent e) {
    setStatusText("Running Tests...");

    //Run Tests
    int currentTest = 1;

    //Check something
    appendStatusText("        Test " + currentTest++ + ":  Checking Something...");
    ..    //Check Something Here
    appendStatusText("            Success");

    //Check something else
    appendStatusText("        Test " + currentTest++ + ":  Checking Something else...");
    ..    //Check Something Else Here
    appendStatusText("            Success");

    //Other tests
    ..    //Run other tests here

    appendStatusText("\nAll tests have completed successfully.  Yay.");
}//End of actionPerformed method

public void setStatusText (String statusText) {
    statusOutput_textArea.setText(statusText);
    statusOutput_textArea.repaint();
}//End of setStatusText method

public void appendStatusText (String statusTextToAppend) {
    statusOutput_textArea.setText(statusOutput_textArea.getText() + "\n" + statusTextToAppend);
    statusOutput_textArea.repaint();
}//End of appendStatusText method 

任何帮助将不胜感激:)

更新

对于那些对解决方案的一般结构感兴趣的人，这里是:

public class RunTestsButtonActionListener implements ActionListener {
    JTextArea statusOutput_textArea;
    JButton testDatabaseSettings_JButton;

    public RunTestsButtonActionListener(JTextArea statusOutput_textArea){
        this.statusOutput_textArea = statusOutput_textArea;
    }

    public void actionPerformed(ActionEvent e) {
        testDatabaseSettings_JButton = (JButton) e.getSource();

        Thread tests = new Thread(){
            public void run() {
                //Disable button and add tooltip
                testDatabaseSettings_JButton.setEnabled(false);
                testDatabaseSettings_JButton.setToolTipText("Running Tests...");

                //Run Tests
                try {
                    statusOutput_textArea.setText("Running Tests...");
                    int currentTest = 1;

                    //Check something
                    statusOutput_textArea.append("\n        Test " + currentTest++ + ":  Checking Something...");
                    ..    //Check Something Here
                    statusOutput_textArea.append("\n            Success");

                    //Check something else
                    statusOutput_textArea.append("\n        Test " + currentTest++ + ":  Checking Something else...");
                    ..    //Check Something Else Here
                    statusOutput_textArea.append("\n            Success");

                    //Other tests
                    ..    //Run other tests here

                    statusOutput_textArea.append("\n\nAll tests have completed successfully.  Yay.");
                } finally {
                    //Enable button and remove tooltip
                    testDatabaseSettings_JButton.setEnabled(false);
                    testDatabaseSettings_JButton.setToolTipText("");
                }
            }
        };

        tests.start();
    }
}

Answer 1

您正在对“Swing 线程”进行检查，您最好在不同的 thread 中执行这些任务(如果发生某些事情/发生变化，它会通知 GUI)。