Question

我的JFrame有一些JButtons。＆＃34;更新＆＃34;按钮（名为JButton1）执行许多填充表单的查询。现在，我希望另一个JButton成为＆＃34;自动更新＆＃34; （名为JButton2），所以我希望它在JButton1ActionPerformed方法中循环，直到不再选择JButton2。当我按JButton2时窗口冻结。

我的代码是对的吗？你认为我需要一个停止按钮吗？

private void jToggleButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                               

       long start = System.currentTimeMillis();
       if(jToggleButton2.isSelected()){
           start = System.currentTimeMillis();

            do{
                do{
                    jButton1ActionPerformed(evt);
                }
                while(System.currentTimeMillis()-start>3000);

            }
            while(jToggleButton2.isSelected()); 
       }

        if(jToggleButton2.isSelected()){
            jToggleButton2.setSelected(false);
        }


    }

Answer 1

Swing是：

单线程;这意味着您不应在Event Dispatching Thread
不是线程安全的;这意味着您不应该更新UI或UI可能依赖于EDT之外的任何内容。尝试解决EDT之外的UI元素也存在风险，因为线程模型可能会返回错误值

如果没有更多问题上下文，我可能会建议使用Swing function Uncheck-SelectAllBox { $cb4Checkbox.Checked = $false } $CBlabel = New-Object System.Windows.Forms.Label $CBlabel.Location = New-Object System.Drawing.Point(10,125) $CBlabel.Size = New-Object System.Drawing.Size(280,20) $CBlabel.Text = "Select a box:" $form.Controls.Add($CBlabel) $cb1Checkbox = New-Object System.Windows.Forms.Checkbox $cb1Checkbox .Location = New-Object System.Drawing.Size(10,145) $cb1Checkbox .Size = New-Object System.Drawing.Size(280,20) $cb1Checkbox .Text = "Checkbox 1" $cb1Checkbox.add_click({ Uncheck-SelectAllBox }) $form.Controls.Add($cb1Checkbox) $cb2Checkbox = New-Object System.Windows.Forms.Checkbox $cb2Checkbox .Location = New-Object System.Drawing.Size(10,165) $cb2Checkbox .Size = New-Object System.Drawing.Size(280,20) $cb2Checkbox .Text = "Checkbox 2" $cb2Checkbox.add_click({ Uncheck-SelectAllBox }) $form.Controls.Add($cb2Checkbox) $cb3Checkbox = New-Object System.Windows.Forms.Checkbox $cb3Checkbox .Location = New-Object System.Drawing.Size(10,185) $cb3Checkbox .Size = New-Object System.Drawing.Size(280,20) $cb3Checkbox .Text = "Checkbox 3" $cb3Checkbox.add_click({ Uncheck-SelectAllBox }) $form.Controls.Add($cb3Checkbox) $cb4Checkbox = New-Object System.Windows.Forms.Checkbox $cb4Checkbox.Location = New-Object System.Drawing.Size(x,y) $cb4Checkbox.Size = New-Object System.Drawing.Size(x,y) $cb4Checkbox.Text = "Checkbox 4 - Select All" $cb4Checkbox.Add_Click({ If ($cb4CheckBox.Checked -eq $true){ $cb1Checkbox.Checked = $true $cb2Checkbox.Checked = $true $cb3Checkbox.Checked = $true } }) $form.Controls.Add($cb4Checkbox)。两个主要原因：

在EDT的上下文中调用Timer，从而可以安全地从内部更新UI
您可以指定更新之间的延迟，从而降低EDT过载的风险，从而导致性能问题

例如......

ActionListener

另一个解决方案可能是使用private void jToggleButton2ActionPerformed(java.awt.event.ActionEvent evt) { long start = System.currentTimeMillis(); if (jToggleButton2.isSelected()) { // You could use an instance field instead and determine // if the Timer is already running or not Timer timer = new Timer(100, new ActionListener() { @Override public void actionPerformed(ActionEvent e) { if (!jToggleButton2.isSelected()) { ((Timer) e.getSource()).stop(); return; } jButton1ActionPerformed(evt); } }); timer.start(); // Just want to point out that this doesn't make sense // As if the button was selected, you'd still be in // your previous loop //if (jToggleButton2.isSelected()) { // jToggleButton2.setSelected(false); //} } }，它为您提供了一种在EDT上执行长时间运行或阻止操作的方法，但它也提供了从EDT内安全更新UI的功能。

看看：

了解更多详情

Answer 2

让我们放下你不应该像我会告诉你的那样克服线程（例如使用var pageTitle = $("#titleHolder").data("page-title");）你需要做这样的事情：

private void jToggleButton2ActionPerformed（java.awt.event.ActionEvent evt）{

SwingWorker

我不关注你的代码是否有效，它只是展示了如何在后台运行，所以你不会冻结你的GUI。

while循环重复actionPerformed的JButton

2 个答案: