SWT：不再有控制手柄

Question

Using eclipse, I have created a Form Editor with 2 tabs for my application. One tab is for GUI support and the other one is for normal text editor. In the GUI page, I have been using hundreds of SWT controls such as tables, sections, buttons, etc.

The problem is when I opened more than 20 files with the Form Editor in my application, I get an exception "SWT: No more handles". I could understand that there is no more control handles for the controls to be created to the Form Editor. I could check the control handles availability and proceed to open the file, if enough handles are available. Otherwise i can not open the file itself.

Is there any possible way to solve this problem?

Answer 1

You may well have reached the limit. Note that the number of handles varies a lot between platforms (macOS, Linux, Windows) so if you plan to run this on different platforms you need to test on all of them.

If you are using SWT classes derived from Resource ( Color , Font , Image , Cursor , ....) then you must call dispose on the object when you are done with it. Failing to do so will leak handles.

You should also try to share these resources - for example don't create a new Color each time. Use a manager class that handles sharing the colors, the manager class can also handle disposing of the resources.

JFace provides manager classes such as ColorRegistry , FontRegistry and ImageRegistry which might be useful.

If this is not enough you will have reduce this large number of controls, perhaps you could use pop-up dialogs to show some of the information when buttons are pressed.