blocks|key|530357|text|鼠标移动事件天生就很慢，因为它在每个像素变化时都会触发。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|530358|要优化整个问题，唯一可以做的就是优化回调处理程序中所做的事情。在你的情况下，你确实有|530359|if+(something)
++doA();
else
++doB();|code-block|syntax|javascript|530360|这意味着，在任何情况下，您都试图显示或隐藏滚动条，即使滚动条已经显示或隐藏。您可以做的是：|530361|if+(scrollBarIsVisible+&&+x>20+&&+x<200)+{
++hideScrollBar();
++scrollBarIsVisible+=+false;
}
else+if+(!scrollBarIsVisible)+{
++showScrollBar();
++scrollBarIsVisible+=+true;
}|530362|这样，当从内部边界切换到外部边界时，您只需修改元素的可见性(这可能是一项繁重的操作，因为它可能需要重新布局内容)。这应该会大大降低计算运算量。|530363|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

A mouse moved event is inherently slowly since it's fired on every pixel change.

The only thing you can do to optimize the whole issue is to optimize what you do inside the callback handler. In your case you do have

<pre><code>if (something)
 doA();
else
 doB();
</code></pre>

This means that in any case you are either trying to show or to hide the scrollbar even when it's already shown or hidden. What you can do is:

<pre><code>if (scrollBarIsVisible &amp;&amp; x&gt;20 &amp;&amp; x&lt;200) {
 hideScrollBar();
 scrollBarIsVisible = false;
}
else if (!scrollBarIsVisible) {
 showScrollBar();
 scrollBarIsVisible = true;
}
</code></pre>

So that you only modify the visibility of the element (which can be a heavy operation since it may require to relayout things) when switching from inside the bounds to outside and viceversa. This should lower the computational operations by a lot.

blocks|key|530400|text|如果您所有的代码都是在Event+Dispatch线程中执行的，则可能会导致问题。看一下这个trail，并尝试将执行大量工作的任何代码放在SwingWorker线程中。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|530401|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html|1|http://docs.oracle.com/javase/7/docs/api/javax/swing/SwingWorker.html^0|1A|5|0|1X|B|1|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]|$A|R|B|S|1|T]]|C|$]]|$1|D|3|-4|5|6|7|U|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]|L|$5|G|H|I|C|$J|M]]]]

If you all your code is being executed in the Event Dispatch thread it could be causing problems. Have a look at this <a href="http://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html" rel="nofollow">trail</a> and try to put any code that does a lot of work in a <a href="http://docs.oracle.com/javase/7/docs/api/javax/swing/SwingWorker.html" rel="nofollow">SwingWorker</a> thread.

blocks|key|2846034|text|您的代码没有得到很好的优化。实际上，它将始终调用show或hide滚动条方法。您可能应该修改它，因为它只在可见时才隐藏它，只有在隐藏时才显示它。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2846035|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Your code is not very well optimized. As it is, it will always call either the show or hide Scrollbar methods. You should probably modify it such as it hides it only if visible and it displays it only if hidden.

blocks|key|530481|text|下面的方法似乎对我来说很好。请注意，事件的处理速度相当快：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|530482|++public+static+void+main(+String[]+args+)+{
++++EventQueue.invokeLater(+new+Runnable()+{
++++++@Override
++++++public+void+run()+{
++++++++JFrame+frame+=+new+JFrame(+"TestFrame"+);
++++++++JPanel+content+=+new+JPanel(+new+BorderLayout()+);

++++++++final+JLabel+mousePosition+=+new+JLabel(+"Unknown"+);
++++++++content.add(+mousePosition,+BorderLayout.NORTH+);

++++++++content.addMouseMotionListener(+new+MouseMotionAdapter()+{
++++++++++@Override
++++++++++public+void+mouseMoved(+MouseEvent+e+)+{
++++++++++++mousePosition.setText(+"X:+"+%2B+e.getX()+%2B+"+Y:+"+%2B+e.getY()+);
++++++++++}
++++++++}+);
++++++++frame.setContentPane(+content+);
++++++++frame.setDefaultCloseOperation(+WindowConstants.EXIT_ON_CLOSE+);
++++++++frame.pack();
++++++++frame.setVisible(+true+);
++++++}
++++}+);
++}|code-block|syntax|javascript|530483|对于hideScrollBar方法，情况可能并非如此|offset|length|style|CODE|530484|entityMap^0|0|0|2|D|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

The following seems to work just fine for me. Note that the handling of the event is rather fast:

<pre><code> public static void main( String[] args ) {
 EventQueue.invokeLater( new Runnable() {
 @Override
 public void run() {
 JFrame frame = new JFrame( "TestFrame" );
 JPanel content = new JPanel( new BorderLayout() );

 final JLabel mousePosition = new JLabel( "Unknown" );
 content.add( mousePosition, BorderLayout.NORTH );

 content.addMouseMotionListener( new MouseMotionAdapter() {
 @Override
 public void mouseMoved( MouseEvent e ) {
 mousePosition.setText( "X: " + e.getX() + " Y: " + e.getY() );
 }
 } );
 frame.setContentPane( content );
 frame.setDefaultCloseOperation( WindowConstants.EXIT_ON_CLOSE );
 frame.pack();
 frame.setVisible( true );
 }
 } );
 }
</code></pre>

That might not be the case for your <code>hideScrollBar</code> method

blocks|key|530496|text|问题解决了。我的应用程序中存在某些性能问题，导致了这种延迟。感谢您的努力以及您提供的信息和建议。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|530497|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Problem solved. There was certain performance issue in my app that caused such delays.
Thank you for your effort and piece of information and advice you provided.

Currently I am experiencing issues with the mouseMoved event in Java - Swing. Briefly, I have got a JPanel and I have attached MouseMotionListener to it, in order to hide or show JscrollPane on the fly:

<pre><code>myPanel.addMouseMotionListener(new MousePresenter());
</code></pre>

I have got my own class that implements MouseMotionListener interface: 

<pre><code>public class MousePresenter implements MouseMotionListener { 

 public void mouseMoved(MouseEvent e) {
 int x = e.getX();
 int y = e.getY();

 if (x&gt;20 &amp;&amp; x&lt;200) {
 hideScrollBar();
 }
 else {
 showScrollBar();
 }

 }

} 
</code></pre>

The issue is that the mouseMoved event is not being fired often enough. Is there any related solution to this issue whilst using MouseMotionListener?

Thank you for your time.

Java Swing - mouseMoved event is fired slowly

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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目前，我遇到了Java - Swing中mouseMoved事件的问题。简单地说，我有一个JPanel，并且我将MouseMotionListener附加到它，以便在运行时隐藏或显示JscrollPane：myPanel.addMouseMotionListener(new MousePresenter());我有自己...

问Java Swing - mouseMoved事件触发缓慢
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