防止 Swing GUI 在调用既访问 Swing 组件且耗时的方法时变得无响应

Question

The following line:

SwingUtilities.updateComponentTreeUI(aComponent);

is making my GUI unresponsive.

When invoking this method to update the laf on a large portion of a GUI, it takes a lot of time, and so makes the GUI unresponsive during this operation.

Since this operation is manipulating the GUI, one can't use a SwingWorker for this either. From the SwingWorker documentation:

• Time-consuming tasks should not be run on the Event Dispatch Thread. Otherwise the application becomes unresponsive.

• Swing components should be accessed on the Event Dispatch Thread only.

The problem here though, is that the operation is accessing Swing components and is time-consuming.

Is there a good way to prevent this unresponsiveness?

Answer 1

Since what you do is changing the L&F, and that might severely impact the appearance and usability of the GUI, ask yourself whether you really want the application to be responsive during that time. It may be better to display a message ("Please wait..." or something) using the glass pane , and freeze the GUI while the L&F is updated.

Now, as others have suggested, you may want to investigate why updating the component tree is so slow.

Answer 2

I was going to suggest looking through your GUI to identify any custom or third-party components that contained a lot of sub-components or that had any unusual or inefficient method to revalidate itself. It looks like that was the case, as you mentioned the date picker was a serious bottleneck.

You suggested splitting the calls to updateComponentTree into several sub-tasks that allow events to occur in between, which might be a 'hack' but isn't too bad, unless the change of font changes the sizes of elements and may cause the user to miss a button etc.

If possible, I would suggest looking at the code in the date picker component and see if you can rewrite it so that instead of hiding the components in the pop-up, it actually removes/disposes them, and recreates them when necessary. This should have no noticeable effect on the responsiveness of the date picker when it's being used, but will certainly speed up component tree updates when the pop-up is not visible.