Question

我处理一些数据库表时显示ProgressMonitor。最初不知道表的数量，因此我创建了ProgressMonitor，其最大值为100.

在SwingWorker线程中开始处理后，它获取表的数量并将ProgressMonitor的最大值设置为表的数量（在我的测试中约为530）。但是，ProgressMonitor仍然以100结束并停止执行线程，即使最大值已增加且进度条准确显示100/530。

知道为什么会这样吗？

actionListener从按下按钮开始ProgressMonitor和SwingWorker（名为TaskThread）：

public void actionPerformed(ActionEvent e) 
{
    String cmd = e.getActionCommand();

    if (cmd.equals("generate")) {
        progressMonitor = new ProgressMonitor(this, "Generating...", "", 0, 100);
        task = new TaskThread();
        task.addPropertyChangeListener(this);
        task.execute();
        genButton.setEnabled(false);
    }
}

PropertyChangeListener更新ProgressMonitor：

public void propertyChange(PropertyChangeEvent evt) 
{
    if ("progress" == evt.getPropertyName() ) 
    {
        int progress = (Integer) evt.getNewValue();
        progressMonitor.setProgress(progress);
        String message = String.format("Completed %d%%.\n", progress);
        progressMonitor.setNote(message);
        if (progressMonitor.isCanceled() || task.isDone()) 
        {
            Toolkit.getDefaultToolkit().beep();
            if (progressMonitor.isCanceled()) {
                task.cancel(true);
            }
            genButton.setEnabled(true);
        }
    }
}

SwingWorker类：

class TaskThread extends SwingWorker<Void, Void> 
{
    @Override
    public Void doInBackground() 
    {
        String tableList = tablesArea.getText().trim();
        script = "";
        String filename = outPath.getText

        // Connect to Database
        Connection conn = getDbConnection();
        if (conn == null)
            return null;

        try {
            // if tableList is blank, get all tables from the From Database afm_tbls table
            if (tableList.equals(""))
            {
                // code omitted
            }
        }
        catch (SQLException se) {
            canWriteFile = false;
            handleError(se);
        }

        String[] tables = tableList.split(",");
        generateRecordCount(conn, tables);

        // Close the connection
        if(conn != null)
        {
            try {
                conn.close();
            }
            catch (Exception ignored) {}
        }

        // Write SQL code to a file
        writeScript(filename);

        return null;
    }

    private void generateRecordCount(Connection conn, String[] tables)
    {
        setProgressMax(tables.length);
        setProgress(0);

        // Loop through tables  
        for (int i = 0; i < tables.length; i++)
        {
            // Get record count for each table
            try { 
                String sql = "SELECT COUNT(*) AS reccount FROM " + tables[i];
                Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
                ResultSet rs = stmt.executeQuery(sql);
                rs.next();

                int recCount = rs.getInt("reccount");
                if (recCount > 0)
                    script += tables[i] + ": " + recCount + nl;

                // Set progress of SwingWorker, ProgressMonitor is updated by PropertyChangeListener
                int prog = getProgress() + 1;
                setProgress(prog);
            }
            catch(SQLException se)
            {
                handleError(se);
            }
        }
    }
}

Answer 1

我弄明白了为什么。所以希望为了别人的利益，这就是问题所在：

SwingWorker.setProgress()函数的边界为0和100，因此即使ProgressMonitor可以处理更高的最大值，SwingWorker线程也会以IllegalArgumentException结束。价值达到101。

即使在增加最大值后，ProgressMonitor也始终以100结束

1 个答案: